Fedora 11 To Default To the Ext4 File System

ffs writes "The next release of Fedora, 11, will default to the ext4 file system unless serious regressions are seen, as reported by heise online. The LWN story has a few comments extolling the virtues of the file system. Some benchmarks have shown ext4 to be much faster than the current default ext3. Some of the new features that matter for desktop users are a faster file system check, extents support (for efficiently storing large files and reducing fragmentation), multiblock allocation (faster writes), delayed block allocation, journal checksumming (saving against power / hardware failures), and others. The KernelNewbies page has more information on each feature. As is the extfs tradition, mounting a current ext3 filesystem as ext4 will work seamlessly; however, most new features will not be available with the same on-disk format, meaning a fresh format with ext4 or converting the disk layout to ext4 will offer the best experience."

Comments

EXT4 in Clusters?

[BountyX]

After doing research on various cluster filesystems I eventually decided on GFS (as opposed to luyster, which seemed a bit overkill). How does EXT4 compare to GFS? Can EXT4 even be used in a clustered environment?

Re:EXT4 in Clusters?

[Forge]

Clustered file systems and local file systems are of necessity different. Most of what makes a clustered FS useful would be pure dead weight on a local FS.

What I would like to see are clustered FSs which are easier to set up. I.e. You go to the 1st machine and start up the cluster config program and it asks: "Is this the 1st machine in your cluster?" Once you say yes there, you go to the other machines in turn, fire up the same program and say no to that question and enter the IP of the 1st machine.

Once all those machines are added, the next step is to select. "Add Local disk to cluster pool" and then you select partitions on your local hard drive that should be in the pool. They don't have to all be the same size either.

Once you have done that for each machine (either by going from one to the next or using the the tool on the primary node to add disks from each one (or a whole group of them if they are already partitioned in the same way).

Then you just start mounting this virtual disk and dumping files to it.

The technology exists to do this. The problem is that each time it's done' its a manual process tantamount to a programing job. Who want's to take up the task of tying all the pieces together to make the setup feel this simple for the user.

Additional functionality (like tuning the FS for Database or Email usage and failover hierarchy) would be added over time and in a way that dose not detract from the simplicity of that basic setup.

Re:EXT4 in Clusters?

[pipatron]

Sounds like someone should learn perl or python and get to it!

Re:EXT4 in Clusters?

[Forge]

We all have our talents.

I have bartered PC repair and System admin services for competent legal advise, accounting service and even medical care on one occasion (Every desktop in my dentist's office had the "worm of the month").

Sensible people do what they are good at and wherever possible get others to do the other things.

This little project may take a day or a few months for a pearl wizard. I'm not sure. I do know it would take me years, if it got done at all.

Re:EXT4 in Clusters?

[Richard W.M. Jones]

Red Hat ship some web based tools called Luci and Ricci which basically do all of this, with a pointy-clicky interface.

Rich.

Re:EXT4 in Clusters?

[Forge]

I have used them.

1. The work for sharing a SAN but are not so useful for clustering local disks.

2. Even doing what they are good at, setup is a bit more tedious than I would like.

BTW: A nice setup menu dose not need to be GUI. Many of the console tools in the system-config-whatever series are nice.

Re:EXT4 in Clusters?

[Anonymous Coward]

Just pointing out that XFS is both a local and clustered file system (okay, technically it's called CXFS when it's in clustered mode). Either way it has the same on-disk layout, just that in clustered mode all the metadata operations are arbitrated by a dedicated server.

My point is that a clustered filesystem is less about the what's on the disk, and more about being able to coordinate metadata operations.

Re:EXT4 in Clusters?

[BBandCMKRNL]

...just that in clustered mode all the metadata operations are arbitrated by a dedicated server.

A single server? Haven't you just given yourself a really nasty single point of failure? What happens if that server crashes or loses communication with the other servers in some manner? Does it recover like a VMS Cluster such that if communication with the Distributed Lock Manager Master Node is lost for too long, everything stops while the remaining nodes decide on a new Master Node and all the nodes re-sync their view of the world? Of course, the VMS DLM manages more than just access to shared disks. It's capable of managing access to any shared entity that is DLM aware.

Re:EXT4 in Clusters?

[Forge]

"Without the 2nd Amendment, the others are just suggestions."

Darn. I really like your .sig

Re:EXT4 in Clusters?

[charlesnw]

Have you tried any of the admin tools to do this? Say those from Centos Cluster Suite for example?

Re:EXT4 in Clusters?

[Forge]

Yes I have and as I mentioned in another post. It's not easy by any stretch.

Re:EXT4 in Clusters?

[LiquidRaptor]

Why would you cluster local disks? If one dies you lose the data on the disk, defeating the point of a cluster. If you want to share the data between the two, there are lots of different types of software that will keep it in sync, however since it's a pretty stupid idea it's not built into any of the standard clusters management tools.

Re:EXT4 in Clusters?

[WNight]

It needs specifying. If you had example configuration files and how they would be changed with various operations, examples of what the dialogs should be like, and other details planned out you could probably get someone to program it pretty easily. It doesn't sound like it'd be a lot of code for a CLI app that helped with some of the discovery/etc.

Re:EXT4 in Clusters?

[nick0909]

Sounds like someone should stop replying to people on slashdot and get to it!

Re:EXT4 in Clusters?

[Anonymous Coward]

And as long as you keep on thinking that way, every project will take "years" for you, and many great tools may not be created, ever. If you start now, maybe this project still will not be done, but the next time you already have the knowledge.

It's not like programming on the level you are speaking of is especially hard to learn, if you do want to. It will require time, in that you are correct.

Re:EXT4 in Clusters?

[Anonymous Coward]

Once you have done that for each machine (either by going from one to the next or using the the tool on the primary node to add disks from each one (or a whole group of them if they are already partitioned in the same way).

This sentence is incomplete, and you are missing a ")".

done' its

"done it's".

Who want's to take up the task

"wants".

for the user.

"?".

Re:Why not ReiserFS?

[Anonymous Coward]

I'm too lazy to read up on ext4, so:

Why not just use ReiserFS? It's definitely faster than ext3.

Because it was convicted of murder, that's why.

Re:Why not ReiserFS?

[Jor-Al]

Because he killed his wife. Don't you read the news?

No

[Anonymous Coward]

Ext4 is not a SAN or distributed filesystem. GPFS/lustre/GFS remain a good choice for that.

Re:No

[Ivlis]

Linux is not communism. Part of the appeal of Linux is that Microsoft abuses its monopoly to eliminate competition (OS/2, BeOS, Wordperfect, QuickTime, etc...). By defending competition, freedom of choice and a free market, Linux defends capitalistic ideals. And people are allowed to sell Linux: SuSE does just that.

Re:No

[Dr. Smoove]

You must be new here

Re:Why not ReiserFS?

[Neuroelectronic]

Because it takes a mad computer scientist to implement it.

How does it compare to ext2?

[Chemisor]

So where can I see some benchmarks showing just how much of a slowdown I can expect after switching from ext2 to ext4? All the benchmarks I see around here compare it to ext3 and to ReiserFS only. Also, is it possible to run ext4 without the journal? Any benchmarks on that? (Oh, and please, don't bother with the reliability lectures. I couldn't care less.)

Re:How does it compare to ext2?

[diegocgteleline.es]

is it possible to run ext4 without the journal?

Yes, it is. And, as you can see in the link, ext4 is faster than ext2. Even with journaling.

Re:How does it compare to ext2?

[coolsnowmen]

You may be able to make one:

ext4_noj = {
    features = extents,huge_file,flex_bg,uninit_bg,dir_nlink,extra_isize
    inode_size = 256
}
# mke2fs -T ext4_noj ext4image.iso
mke2fs 1.41.3 (12-Oct-2008)
ext4image.iso is not a block special device.
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
31296 inodes, 125000 blocks
6250 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=130023424
4 block groups
32768 blocks per group, 32768 fragments per group
7824 inodes per group
Superblock backups stored on blocks:
                32768, 98304

Writing inode tables: done
Writing superblocks and filesystem accounting information: done

But you might not beable to actually use it:

# mount -t ext4 -o loop ext4image.iso /mnt/loop1/
mount: wrong fs type, bad option, bad superblock on /dev/loop/0,
              missing codepage or helper program, or other error
              In some cases useful info is found in syslog - try
              dmesg | tail or so
# dmesg | tail
    ext4: No journal on filesystem on loop0

I use ext4 on my media partition with no problems.

Re:How does it compare to ext2?

[RiotingPacifist]

ext4 vs reiserfs & jfs would be particularly interesting tbh, its hard NOT to be faster than ext3/2.

Ext4 small files performance?

[Dogun]

I still haven't seen sensible benchmarks for ext4 with respect to how large directories scale, interleaved small file read and create, and small-file write with one fsync() at the very end (the only real world case.)

At this point, I have to wonder if the emporer has no clothes, or if the people posting benchmarks are just idiots.

Re:Ext4 small files performance?

[Anonymous Coward]

For those who are not filesystem wizzes, could you expand or provide a link on why this is important? I'm wanting to improve the performance of my boxes like everyone else but understanding the ins and outs of the filesystems is a weak point of mine. Thanks.

Re:Ext4 small files performance?

[Dogun]

Because disks are buffered, and fsyncing after every call (or forgetting to do so entirely) is silly.

I suppose somebody cares about how well they can expect their 124GB file to stream to disk, but for the rest of us mortals, we care about journalling support (check), a toolset (mostly check), and common-case performance, which in the *nix world involves a lot of reading and writing of small files.

I'd also like to see how these things perform under load, or when multiple benchmarks are running simultaneously.

Re:Ext4 small files performance?

[cerberusss]

I still haven't seen sensible benchmarks for [...] small file read and create

This is pretty hard to benchmark with ext4. You see, those small files are a real lively lot. Trying to get them in one line, then wait for the start signal and then start at the same time has been quite an ordeal.

They've succeeded once, but then the mothers noticed the hustle. You'll be glad you weren't anywhere near. You might not think a lot about a fat mother penguin, which just tells me you have never seen a angry penguin charging at you in excess of 100 mph.

Re:Ext4 small files performance?

[kae_verens]

maybe a silly question, but wouldn't running multiple benchmarks simultaneously cause spurious results?

Re:Ext4 small files performance?

[jonaskoelker]

I suppose somebody cares about how well they can expect their 124GB file to stream to disk

I know for certain that I care about big-file performance in almost only these ways:

Can I write the file faster than the network sends it to me?

Can I read the file faster than the application (typically mplayer) needs to consume it?

When I know I shouldn't sit and wait for a larger task to continue, I really don't care how long it takes as long as I can do interactive stuff with good performance and the disk won't still be rattling when I go to sleep. Five minutes? An hour?

I'd rather have effort put into usability of disk management tools: four-way on-line resizing (left/right end moving left/right), on-line repacking (defragmentation) and on-disk format conversion, on-line repartitioning [which goes beyond the scope of ext4, of course] and things like that. A versioning file system would be cool, and btrfs snapshots sound like they'd be nice as well .

But that's the desires for my usage pattern, and I acknowledge that there are others.

Re:Ext4 small files performance?

[diegocgteleline.es]

You can see some of those benchmarks in this paper which explains the block allocator improvements that have been done in ext4.

Re:Ext4 small files performance?

[blueg3]

What he really means is having a new benchmark that has a combination of loads from other benchmarks -- this is closer to a real-world case than any one individual benchmark, which is some kind of extreme case.

Re:Ext4 small files performance?

[Anonymous Coward]

At this point, I have to wonder if the emporer has no clothes, or if the people posting benchmarks are just idiots.

Then do the goddamn benchmark yourself and post the results. If the validity of EXT4 is that important to you, lend a hand instead of sitting on your ass and complaining.

Re:Ext4 small files performance?

[Anonymous Coward]

To expand on this, Reiser4 destroyed everything else in a lot of benchmarks. But then you use it in real life for a year and it starts locking up the filesystem for 15+ seconds at a time doing god knows what.

Re:Ext4 small files performance?

[swillden]

I know for certain that I care about big-file performance in almost only these ways:

Can I write the file faster than the network sends it to me?

Whether or not that's at all difficult depends on the network in question. You could just about carve the data into stone tablets with a hammer and a chisel at the speed my cable modem delivers it, but when I'm moving files between machines on the LAN (Gig-E), it's a very different story.

Re:Ext4 small files performance?

[TooMuchToDo]

This is the part where I tell you I have a 50Mb/s down connection from Comcast that gets close to that, and you come search me out with an ice pick.

Re:Ext4 small files performance?

[swillden]

:-)

Although, 50 Mbps is only a little over 5 MBps, which is an I/O rate even an ancient laptop drive with a lousy file system can handle.

Do they give you a decent upstream with that?

Re:Ext4 small files performance?

[TooMuchToDo]

7Mb/s up. Not horrible, but it's no FIOS.

Re:Ext4 small files performance?

[inKubus]

I'd like my filesystem to come with a fast way to backup incrementally without having to read all the metadata. Like a lightweight journal, a changelog only. I know Veritas and Tivoli have had journalling services that poll the filesystem for changes for a while. Would it be so hard to break the journals up into a few parts so I only have to look at changed files when I'm backing up incrementally. Or do they already do this?

Re:Ext4 small files performance?

[Achromatic1978]

You should just have forked out the extra amount for the business package. I just had Comcast out today, upgrading my 8/1 connection to 50/10. 5 static IPs, no port blocking, no throttling.

Re:Ext4 small files performance?

[Dogun]

It's not that important to me. But for once, I'd love to see fairly exhaustive benchmarks like I used to see for Reiser3. At least, at the time, they felt pretty good.

I imagine Ext4 is actually quite good. It would be nice to be able to see some quantification of how good that was not obviously flawed.

Re:Ext4 small files performance?

[Dogun]

Alright! And NOW I feel somewhat excited about ext4. I just wish for a change /. were posting things like this instead of the article in the summary.

Re:Ext4 small files performance?

[TooMuchToDo]

Did go with the business package (no total transfer caps with the business package). $199/month. I don't have a need for the static IPs, as I VPN back to datacenter space I have at Equinix.

Re:Ext4 small files performance?

[Anonymous Coward]

I smell a reiser-bot?

Re:Ext4 small files performance?

[WindShadow]

I put my backup raid on ext4 and noted that the write speed for large (2-8GB) files, written one at a time, is about 25% faster than ext3 on the same hardware and raid config, both using noatime.

The bad news is that if you have a kernel with no ext4 support and just do a mount command, it appears that the kernel will mount as ext3 and then screw up the data. Forcing the ext4 module to load or using the ext4 f/s type will prevent this.

Sorry, no information on small files at all, that's not how I'm using the storage. However, there is a tool to defrag in cases where some write pattern causes a fragmentation issue, I guess that's a good thing.

Also note: I didn't play with the stride parameter, previous use with ext3 indicates that if you have a software raid five or six this will really help write performance.

A few answers

[E. Edward Grey]

I'll save you the intense effort it must take to scroll up and read the summary. The answer is COMPATIBILITY.

"As is the extfs tradition, mounting a current ext3 filesystem as ext4 will work seamlessly; however, most new features will not be available with the same on-disk format, meaning a fresh format with ext4 or converting the disk layout to ext4 will offer the best experience."

For my own purposes, I can't use ReiserFS because I can't stop thinking about that guy when I install it. Just...ick.

Re:A few answers

[camperdave]

As is the extfs tradition, mounting a current ext3 filesystem as ext4 will work seamlessly;

Shouldn't that be the other way around? If you mount an ext4 filesystem as ext3 the system will work, using only the ext3 subset of ext4. However, if you mount an ext3 as ext4 the system will try to use ext4 data structures which are simply not on the disk.

... or am I missing something?

Re:A few answers

[eparis]

Yes you are missing something. :) The superblock on all extX say what features they support. So when you mount ext3 as ext4 the mount code can look what features that FS supports and use what new features it has available that won't break it as ext3. If you mount and ext3 fs as ext4 you'll get all of the benefits of ext4 like the enhanced inode allocator and what not, but you won't get extents so your huge file support is limited just like ext3) An ext4 fs can NOT be mounted as ext3 as the files will be stored using new features (like extents) which ext3 doesn't understand. Make sense? There will be (or is?) a conversion tool which will be able to downgrade ext4, but you can't just mount backwards.

Re:A few answers

[Chrisq]

As is the extfs tradition, mounting a current ext3 filesystem as ext4 will work seamlessly; Shouldn't that be the other way around? If you mount an ext4 filesystem as ext3 the system will work, using only the ext3 subset of ext4. However, if you mount an ext3 as ext4 the system will try to use ext4 data structures which are simply not on the disk. ... or am I missing something?

Your missing something. Geeks are only worried about upgrading to the latest, so mount an ext3 and it will create the extra data for you. The other way round might work, but testing fallback is so unexciting

Re:A few answers

[Orange Crush]

^I'm less concerned about what the guy did who spearheaded its design, and more about it becoming abandonware.

Re:A few answers

[pak9rabid]

For my own purposes, I can't use ReiserFS because I can't stop thinking about that guy when I install it. Just...ick.

For me, I can't use ReiserFS because I prefer to keep my data. I've had ReiserFS screw me over twice now. Once where the data was completely lost, and once where the data was damn-near lost but luckily recoverable with only a few files getting corrupted.

Re:A few answers

[Dragonslicer]

It's like using software on new versions of Windows: usually, software that works in Windows 95 will still work in Windows 98, but software written for Windows 98 probably won't work on Windows 95. The newer version can still work with partitions from the old version, but the old version can't understand partitions made with the new version.

Re:A few answers

[wiredlogic]

Actually, ext4 can be mounted as ext3 provided extents are disabled when creating the ext4 fs. This may be useful for someone who wants some of the new features of ext4 but needs to mount the media on a machine that can't be upgraded to support it.

Re:A few answers

[ion.simon.c]

*has been using Reiser since 2002 and has yet to lose a byte*

(Having said that, I'mma switch my XFS and Reiser partitions to EXT4, just as soon as .28 is marked as stable in the Portage tree.)

BTW: Anecdotal evidence sucks. :(

Re:A few answers

[pak9rabid]

Under normal usage, I too have not experienced any nastiness with ReiserFS. However, I've found when I'm pounding the hell out of the filesystem, it doesn't seem to keep up so well. Admittedly, these incidents were not the result of normal usage scenarios (rsync'ing large media volumes and rapid reads via a program written in C to backup roughly 222 gigabytes of image files); operations that are not too uncommon in the enterprise environment.

Re:A few answers

[ion.simon.c]

Is Reiser the only FS you've used that fails under those loads?

Re:A few answers

[pak9rabid]

Yup. We use ext3 for just about everything on our servers and it's never failed me under extremely high IO.

Re:Why not ReiserFS?

[Anonymous Coward]

Some of the minor features are just... less than desirable.

ReiserFS is good...

[Anonymous Coward]

for when you need to partition your wife.

Re:ReiserFS is good...

[Anonymous Coward]

...or when you need to resize her...

Re:ReiserFS is good...

[LrdDimwit]

Just don't try to fsck the partition. That would be ... awkward.

Fresh format vs conversion

[MacColossus]

I read the article and it looks like converting from ext3 to ext4 may be problematic.

I do not propose offering migration from ext3 by default, at this point, due to bugs in that process, and extra risk involved. Perhaps an "ext4migrate" boot option could be used to expose it for further testing.

Re:Fresh format vs conversion

[radarsat1]

Good to know. Personally I'll be happy to use ext4 on new disks or when I'm really doing a complete re-install, but I'm in no hurry to "upgrade", seeing as my current ext3 disks are working just fine. I played with different filesystems once until I got some corruption and realized that one of the advantages of ext3 is that it's been around long enough that there are lots of tools to help with recovery and checking. So I'll probably stick with what I know until I have an opportunity to try out ext4, but I'm not going to go and reformat my disks right away.

Re:Fresh format vs conversion

[Anonymous Coward]

Surely moving over wont be too difficult.

Create a new ext4 partition. Install and boot up. Mount you old /home/ ext3 partition (or whatever else you want to move over) and copy the files up. OK, it won't be a quick process and doesn't really work for those whose /home/ is 80% of the disk. But its an option.

Re:Fresh format vs conversion

[electrosoccertux]

It's not even that.
ext4 functions as an enabled flag on ext3.
So you can transition without formatting, or anything.

Re:Fresh format vs conversion

[incripshin]

I upgraded, and eventually it erased my root directory. I'm presently trying to figure ext4 out and writing a program that should recursively recover files from /etc and my home directory. I recommend nobody use ext4 for at least five years.

Re:Fresh format vs conversion

[gzipped_tar]

Not always. If your old ext3 filesystem uses 128-bit inodes, they'll have to be converted to 256-bit by tune2fs. However, this may not be guaranteed to be successful. Actually it failed miserably on my system (it was several months ago and I don't know whether the e2fsprogs has been improved on this by now). I made backup before carrying out the experiment so after the failure I just reformatted the partition as ext4, updated fstab and recovered from backup.

Re:Fresh format vs conversion

[JesseMcDonald]

So... you upgraded to a brand-new filesystem without first making a backup? Some glitches are to be expected at this point, just as when ext3 first came out. If everyone followed your advice and avoided ext4 "for at least five years," however, those glitches would never be found, much less fixed.

Re:Fresh format vs conversion

[incripshin]

Nobody starts backing up until their first disaster.

Re:Fresh format vs conversion

[Anonymous Coward]

Nobody starts backing up until their first disaster.

You mean: "Nobody starts backing up until after their first disaster.

Re:Why not ReiserFS?

[grumbel]

ReiserFS isn't actively maintained. In addition to that ext3 and now ext4 have learned quite a few new tricks since ReiserFS first appeared, you can now online resize an ext3 filesystem, it supports hashed b-trees, which should speed up directory handling, it is getting an online defrag tool and a bunch of other goodies. So many of the benefits that ReiserFS originally brought to the table can now be have with ext3 or ext4.

Re:Why not ReiserFS?

[Anonymous Coward]

that's just wrong

So Ext4 in RH7 ?

[Culture20]

After several more years testing in Fedora releases?

Re:So Ext4 in RH7 ?

[macxcool]

Exactly what I was thinking ;-)

Re:So Ext4 in RH7 ?

[eparis]

It's already a technology preview in RHEL 5.3.

Thank you Red Hat

[eparis]

I'm glad to see Red Hat and Fedora taking the hard steps to push our technology forward. Precious few organizations employ people to work on things like this, instead expecting others to do the hard work to create and integrate disruptive core technologys. I know Red Hat employs people to work full time on ext4 and they have a person working full time on btrfs (which by all early accounts is supposed to be revolutionary and kick the crap out of everything else out there [even the fabled ZFS] (it pains me to say thanks to oracle for btrfs, but one of their employees is the primary driver) Someone has to do the hard work of being a leader, putting in engineering time, and fixing the bugs before the fanboys can consume (and all too often get credit for) new technology. Thank you Fedora for both the freedom and the constant drive to be on the leading edge of technology.

Re:Thank you Red Hat

[DiegoBravo]

And thanks to the Fedora users, apparently the first large user base that will (hopefully in full knowledge) be testing this thing for the benefit of the rest of the community (nothing against RedHat, somebody have to do the first step.)

Re:Thank you Red Hat

[Abreu]

There is a saying in Spanish, which translated says:

"They are braver than the first men to try oysters!"

Re:Thank you Red Hat

[TheLink]

I wonder if many "edible discoveries" involved drunk young men daring each other to eat something.

Stuff like: century eggs, tofu, lutefisk, casu marzu (not sure if the last is really that edible ;) ).

Re:Thank you Red Hat

[Anonymous Coward]

... kebabs, in England these are only edible by drunken people. Ever tried to eat a kebab, from your local Turkish outlet, when you're sober? *shudder*

Re:Thank you Red Hat

[Just Some Guy]

Or extreme starvation: "we dropped our fish in the fireplace, but we'll surely die if we don't eat it anyway!"

Re:Thank you Red Hat

[Eil]

Thank you Fedora for both the freedom and the constant drive to be on the leading edge of technology.

So that more mainstream distributions like Ubuntu can implement the technologies after they've been bug-tested.

</rimshot>

Re:Thank you Red Hat

[mikael]

According to the natives of many tropical jungle tribes, they watch what the animals eat, and adjust their diets accordingly.

Re:Thank you Red Hat

[drinkypoo]

Thank you Fedora for both the freedom and the constant drive to be on the leading edge of technology.

Thank you, Fedora users, for not abandonding Red Hat when they started demanding money for their operating system and only giving away their alpha test version. You truly provide the earliest bug reports and suffer the most damage. The whole team is truly grateful.

Re:Thank you Red Hat

[Raenex]

How did the animals learn? Check out these parrots that eat clay so they can eat poisonous nuts and seeds:

http://www.highlightskids.com/Science/Stories/SS1201_parrotseatDirt.asp

Re:Thank you Red Hat

[mikael]

Animals learn from watching each other. Perhaps these parrots were able to determine that eating seeds that had fallen in this layer of clay were more edible that seeds from other areas. Then when they went to other areas, they found out that they could eat the seeds there.

Maybe they have a sense of taste/smell that can detect alkaloids and suitable antidotes. Mammals can smell salt/humidity and know instinctively that if they eat something salty, they should drink water.

Re:Thank you Red Hat

[TheLink]

Lots of birds eat grit so that they can chew their food in their gizzards.

Maybe a parrot that accidentally ate clay one day figured it out, and it eventually became a common tradition amongst parrots (who are intelligent enough to copy each other).

Re:Thank you Red Hat

[giuda]

Casu marzu? Are you from Sardinia?

Re:Thank you Red Hat

[TheLink]

No.

Re:Thank you Red Hat

[giuda]

Ok. Then I am surprised that someone outside of Sardinia knows about it. It's really a disgusting dish (cheese with LIVE worms), but a lot of people LOVES it.

This is all very well, but...

[Anonymous Coward]

ext3 has had years to establish itself as a reliable performer in heavy real-life situations. Why is everybody being so ambivalent towards ext4 when it's relatively new and not particularly trustworthy as of yet?

Re:This is all very well, but...

[SaDan]

People are looking forward to ext4 because ext3 has performed so poorly compared to ReiserFS. No one wants to touch ReiserFS, regardless of its performance advantages over anything out today, because Hans was a psycho.

In a previous job, we tried everything we could to use ext3 for one of our server-based products, but the performance was never good enough compared to ReiserFS v3.

Hopefully the ext4 folks have learned how to implement all the excellent ideas Hans Reiser came up with between ReiserFS v3 and ReiserFS v4.

Re:This is all very well, but...

[Anonymous Coward]

No one wants to touch ReiserFS, regardless of its performance advantages over anything out today, because Hans was a psycho.

There were a lot of other reasons but in hindsight they are probably related to that. The system was seen as far too perfect to need recovery tools - despite the obvious problem of it running on imperfect hardware which occasionally stuffs up and requires the use of recovery tools.

People tend to be a bit reluctant to deploy things that can't be fixed into production environments. I've got absolutely no idea why SUSE took it up at such an immature point, and unfortunately due to many files being of a size it was not optimised for (10s of GB) it performed very badly on the production system I saw it on.

Re:This is all very well, but...

[SaDan]

Eh? ReiserFS had decent recovery capabilities, and I used them extensively when hardware failed in horribly ways on RAID systems. Instead of losing an entire filesystem, you might lose a couple files here and there.

My track record for recovering blown up RAID arrays running ReiserFS is much better than recovering those running EXT2 or EXT3.

Re:Why not ReiserFS?

[KasperMeerts]

Maybe wrong, but definitely hilarious.

Fedora 10 bugs

[ichthus]

Excellent. This will be a great feature for F11. Now, if they could just get Fedora 10 booting with an nvidia fakeraid, I'd be happy. And, fix the performance issues with intel GMA graphics, that'd be dandy too.

Fedora is my favorite distro, but this fakeraid bug is ridiculous -- keeping me from running F10 on my desktop. Sure runs nicely on my Samsung NC10, though.

Re:Fedora 10 bugs

[Anonymous Coward]

Both of the bugs you listed have been corrected for F10, according to the bugs reports you linked.

Re:Fedora 10 bugs

[Anonymous Coward]

And, the links are reversed. But, one is "assigned" and the other is a dupe of another bug that is fixed in the "next release". Neither are fixed for Fedora release 10.

You Can Always Tell The Pioneers ...

[Prototerm]

... They're the ones with the arrows in their backs! It's changes like this that underscore treating new distro versions as a public beta. Chances are, this or some other new feature will cause someone real pain. It's always a good idea to make sure that that someone is *not* you. Whether it's Fedora or OpenSuse, or Ubuntu, oftentimes features are added that aren't really ready for prime time. Trust no one.

Re:You Can Always Tell The Pioneers ...

[Anonymous Coward]

... They're the ones with the arrows in their backs!

Um, if they're really Pioneers, shouldn't the arrows be sticking out of their chests?

Re:You Can Always Tell The Pioneers ...

[BTG9999]

Do you not know what Fedora is? Fedora is a bleeding edge distro. One that is openly acknowledged by Red Hat as being their Beta testers for new technologies that might eventually make it into RHEL. So this is just a standard thing Fedora does.

Re:You Can Always Tell The Pioneers ...

[ems2004]

I fully agree with your opinion. Fedora quality is on a constant decline, but unfortunately, all the competition is also not that rosy (no matter what ubuntu fans might think).

Re:You Can Always Tell The Pioneers ...

[ems2004]

Yes, it is bleeding edge but I am stuck with Fedora 8 on my Acer aspire 3000 laptop because the bleeding edge 9 and 10 don't have X display working for it. I tried ubuntu 8.10 but that also has the same problem(i know i know .....do this ..do that). Even the install does not go thru because X display can not start properly. At least the bleeding edge should not start bleeding already working solutions.

Re:You Can Always Tell The Pioneers ...

[charlesnw]

Um. Regressions happen. Report a bug. Seriously. Why do you complain about this? It's part of the process of any software upgrade.

Re:You Can Always Tell The Pioneers ...

[halltk1983]

On my Acer Aspire 3005, I run Xubuntu 8.10. Display works, wireless works, power management works. Other than Gentoo, it's the only distro (or OS) that I've gotten to be stable on it.

Re:Why not ReiserFS?

[Anonymous Coward]

In fact suse changed their defaults from reiser to ext3 long time ago. The main reasons were: scalability on SMP, xattrs performance, lack of mainteinance, lack of a upgrade path...

Re:Why not ReiserFS?

[xonar]

Seconded

Re:Why not ReiserFS?

[mahdi13]

Not to mention ext3 doesn't lose random OS files in the wake of a sudden power failure like reiserfs does. I might be alone on this event but after it happening on 3 different systems at 3 different times I'd think it would be documented more. I've always thought reiserfs was overrated and even if there is a speed increase data integrity is a lot more important to me.

It doesn't bother me that the creator is a convicted murderer, it does bother me that the file system gets away with murder all the time.

Re:Why not ReiserFS?

[adamgundy]

me too.. power outage = partially broken filesystem. reiserfsck = completely broken filesystem. and a day long session of trying to fix things on a critical machine. end result: we now use ext3 everywhere...

Re:Why not ReiserFS?

[Anonymous Coward]

Seconded

You two make a good RAID-1.

Re:Why not ReiserFS?

[grumbel]

In the very very early days of ReiserFS, it had the tendency to trash files and it happened to me a couple of times, but it got fixed at some point and I didn't had any problem with that after that and have used ReiserFS3 happily for years.

Then on a new system (Ubuntu8.10) I tried XFS just for a change and I had file loss on day one, followed by continual file loss after each and every crash of the system (buggy Nvidia driver). The recommend solution to this was switching of hard drive cache, which however didn't change anything at all for me. I have replaced XFS with ext3 after that, since XFS seems to be completly unable to not lose files on crashes, and so far with ext3 I haven't lost a single file.

With all that talk about file system performance and stuff, it would be really nice to get a bit more information on what really matters: How good is a filesystem at keeping your files safe. All information on that seems anecdotal at best.

fs-driver

[FunkyELF]

ext3 seems to be the nicest at the moment for native linux support and painless Windows support for dual boot machines. Easier than using NTFS in Linux. Last I heard ext4 wouldn't work with Windows.

Re:fs-driver

[Anonymous Coward]

Indeed - not natively, but (free!) stuff exists to access ext2 & 3 partitions from Windows. Not ext4 yet...

Re:fs-driver

[Anonymous Coward]

Easier than using NTFS in Linux.

Uh, how, exactly?

Additionally, ext3 is not 'painless' in Windows. Ever tried to share something on an ext3 partition? It won't do it, because of the different security settings.

Re:Why not ReiserFS?

[mortonda]

Critical systems should be on a UPS and have frequent backups... it makes those session much less drastic. That said, ext3 has always been an easier repair.

Re:Why not ReiserFS?

[blueskies]

And to think at one time ReiserFS used to murder all of the other FSs....

Re:Why not ReiserFS?

[adamgundy]

there was a UPS.. it didn't last long enough to cover the entire outage. why didn't it shut down a few minutes before the power ran out? because we were using a logging filesystem, and we needed the machine to run as long as possible.. the backup was not as useful as it should have been (incomplete, sigh). I can't remember a time when ext3 failed to be repaired (sometimes with a little manual help recovering files from lost+found). I have a *very* clear recollection of reiserfs eating huge chunks of the filesystem as it 'repaired'.

Ext4 in Ubuntu jaunty jackalope

[the_one(2)]

Apparently there is a serious risk of data loss at this time in case of power loss (at least in ubuntu). http://ubuntuforums.org/showthread.php?t=1040199

Re:Ext4 in Ubuntu jaunty jackalope

[Anonymous Coward]

That's Ubuntu for you.

Re:Why not ReiserFS?

[phantomlord]

I have my home server on an UPS, but it didn't stop the power supply connector on my motherboard (Tyan S2460, it happened to other people on slashdot too) from shorting out, bringing down my system. A UPS is a tool to help prevent catastrophic failure, but it isn't guarantee.

a filesystem should help insulate the data during sudden power loss, not pretty much guarantee that it will thrash all of your data. Sometimes, shit just happens despite the best planning.

FS choices in the Datacenter

[unixluv]

One of my biggest beefs with ext3 in the data center is the required fsck periodically. Redhat won't support jfs or xfs (which I can get from CentOs) but some vendors won't support anything that isn't on their supported platform list (IBM Clearcase for one).

So is ext4 going to force a fsck at boot, which takes 1/2 a day with ext3 on some of my multi-Tb systems? Will Redhat finally adopt a better server filesystem? These are the questions that some of us doing professional Redhat support are asking.

Re:FS choices in the Datacenter

[Per Wigren]

So turn it off the periodical fsck then:

tune2fs -c 0 -i 0 /dev/foo

It's perfectly safe as long as the underlying blockdevice is safe (RAID).

Re:FS choices in the Datacenter

[Gerald]

It's perfectly safe as long as the underlying blockdevice is safe (RAID).

I'd rather have a filesystem that's perfectly safe period, thankyouverymuch.

Re:FS choices in the Datacenter

[Sadsfae]

One of my biggest beefs with ext3 in the data center is the required fsck periodically.

And what keeps you from just running tune2fs and turning off the disk checking (or making the check interval ridiculously long) ?

Re:FS choices in the Datacenter

[Zaiff Urgulbunger]

I never understand why it [ext3] needs checking anyway; I thought the point of journaling was that it can recover if there is a power outage or whatever whilst writing, so FS integrity is assured?

And if there is a risk of corruption due to power outage (or hard crash), then why not write a /forcefsck when the system boots, and remove it when the system shuts down. That way, if the system is not cleanly shutdown, this can be automatically detected and an fsck run then and only then?!

But I guess I'm missing something! :D

Re:FS choices in the Datacenter

[Anonymous Coward]

You can disable that requirement (which other distros do). Red Hat only defines that as a default because it is good practice to fsck every now an then, because the journaling does not prevent corruption in the case of silent failures from disks (which I have seen in the real world, thank you).

Re:FS choices in the Datacenter

[jabuzz]

Take LVM snapshots and do periodic background fsck's, if they pass reset the last check time. If they fail set it to some time in the distance past and raise an alert.

However I have to agree, my biggest beef with Redhat is their boneheaded sticking with ext3, and the utter waste of effort that is ext4. It would be far more sensible to have picked either JFS or XFS (I don't care which) and used that instead.

Re:FS choices in the Datacenter

[xlotlu]

One of my biggest beefs with ext3 in the data center is the required fsck periodically.

It doesn't require it, and never did (ext2 included). It's just some defaults various people consider sane. Do you really trust your hardware? Then:
tune2fs -c 0 -i 0

Redhat won't support jfs or xfs

One of my biggest beefs with xfs is that fsck.xfs does nothing. Nada. Simply returns 0. You want to actually check your filesystem you say? Then go have fun with xfs_check and xfs_repair.

All in all, it's nice that Fedora pushes ext4 forward. But I'd rather let some time pass before I replace any of my xfs partitions..

Re:FS choices in the Datacenter

[xlotlu]

I never understand why it [ext3] needs checking anyway; I thought the point of journaling was that it can recover if there is a power outage or whatever whilst writing, so FS integrity is assured?

First, there always could be some hidden bug triggered by an infinitely improbable combination of circumstances lurking around ready to eat half the data you commit to disk.

Second, even if the software were perfect, bad memory, a bad sata/raid controller, or even a bad cable can cause a filesystem to get screwed.

But I guess I'm missing something! :D

Yeah, hardware is flaky. Periodic checking is the right thing to do for the overwhelming majority of users (e.g. the GP that couldn't figure out to man tune2fs). Those that need their servers online fast after a reboot, and properly mitigate against hardware failure (backup their data _incrementally_) are likely to know how to tune2fs.

Re:FS choices in the Datacenter

[unixluv]

If you ever tried to restore a several Tb filesys, you'd know why I don't do that.

Yes, I am perfectly aware of tunefs. I stand corrected on the required fsck, but its required as far as I'm concerned. I appreciate the replies that say the fsck will be much faster.

Re:FS choices in the Datacenter

[evilviper]

One of my biggest beefs with ext3 in the data center is the required fsck periodically.

The Ext guys need to take a lesson from UFS2 (FreeBSD 5.0, circa 2003) and perform the fsck in the background, at low priority, while the system is up and fully functional.

I hear Btrfs is going to eventually get similar capabilities, so maybe the answer is to just keep waiting.

Re:FS choices in the Datacenter

[Convergence]

I've been using a trick since the ext2 days to reduce fsck times by a lot.. Reduce the inode count. I seem to recall EXT3 allocates 1 inode for every 16kb of diskspace by default. This means 20 million inodes on a 300gb partitian. 2.5gb scanned, on every fsck! A lot of the time, this is overkill. I generally run my parititians with 1/5 to 1/20 this number of inodes. I don't have any partitians formatted under the defaults to compare this to, but a mostly full 300gb partitian, with 1M inodes and 50k files, fsck's in under 10 minutes.

One reason Ext4 has faster fsck times because it tracks which inode groups are totally unused, and it avoids scanning them.

Re:FS choices in the Datacenter

[Per Wigren]

No filesystem in current Linux is going to save you from silent bitflips. The only way to be protected from that is to use checksumming and parity calculation. Either you implement that in the block device (classic RAID) or in the filesystem (ZFS Z-RAID or similar) or you have to live with the possibility of corrupted data.

Re:FS choices in the Datacenter

[mikechant]

Err...you should know it's 'partitions' not 'parititians' or 'partitians'

Re:FS choices in the Datacenter

[ploxiln]

Yeah I used to format my home partitions with an inode per 128k or so for this reason, as I had a bunch of mp3s and such. Then one day I wanted to build firefox. Well it turns out that there are more files in a firefox source archive than I had inodes on that particular partition, and the only way to get more inodes is to reformat.

Lesson learned. On ext3, go with the default inode frequency.

Re:FS choices in the Datacenter

[bill_mcgonigle]

It's perfectly safe as long as the underlying blockdevice is safe (RAID).

And the filesystem driver is bug-free.

Re:Why not ReiserFS?

[TheLink]

"Why not just use ReiserFS?"

Vendor lock-in?

This is Fedora!

[foobat]

who cares about ext4 when the release name is Leonidas http://www.redhat.com/archives/fedora-devel-announce/2009-January/msg00004.html

But does it run on Seagate Bricks?

[CranberryKing]

ST3500320AS fw:SD15 you bastards!

Re:Why not ReiserFS?

[RiotingPacifist]

ext3 fscks were just too slow for me, reiser is may be a bit unstable (my laptop's hardware is screwed the HDD bales out and the pci-bus lock up randomly but ive only needed to do a whole disk fsck once (200G in 20min wasnt too bad), so im yet to see it)

Because anything valuable is backed up and given how slow ext has generally been i have no intention of using ext for anything that doesn't contain critical data, and ill stick with reiserfs/jfs until a better alternative btfs, et al, comes out.

Lunatic Fringe

[turgid]

This is good news. All those Fedora folks can be beta testers. In five years or so I'll consider going from ext3 to ext4. It's only about a year since I went to ext3. I figured it must be OK by now since there haven't been any scare stories. I used to use Reiser before ext3 was stable.

xfs is really over-rated. I used to work on an "Enterprise" storage appliance that used xfs. It was scary. Don't go there. Also, avoid anything from IBM.

chasing the version number game

[Anonymous Coward]

Fedora instead of trying to improve its engineering, quality of releases is running after cheap publicity and version number to match up to OpenSUSE and UBUNTU.

What's Best for SSDs?

[scruffy]

Is ext2 a better choice because it limits the number of writes, or is that a silly worry?

Re:What's Best for SSDs?

[Abcd1234]

Probably a silly worry. Every SSD out there provides it's own wear-leveling hardware, so the FS you use is fairly immaterial. Heck, most (all?) gear out there doesn't even provide a mechanism for direct access to the underlying storage, so you *can't* do the leveling in software (ie, with something like JFFS, etc) even if you wanted to.

Re:Why not ReiserFS?

[swillden]

Not to mention ext3 doesn't lose random OS files in the wake of a sudden power failure like reiserfs does. I might be alone on this event but after it happening on 3 different systems at 3 different times I'd think it would be documented more.

How long ago was that?

I've used reiser almost exclusively for over five years now, including on my multi-TB home file server which has suffered lots of crashes due to power and -- for a time -- hardware issues (bad mobo).

In all that time, I've abused the heck out of the file system, including using one reiserfs that was on a failed RAID array that was forcibly reassembled and had missing data. I did lose a few files in that case, but that's the only time, and I was impressed reiser was able to rebuild a working FS at all.

I particularly like the fact that growing reiser file systems is fast, and shrinking them without unmounting them is possible. I make fairly heavy use of LVM and rearrange storage frequently, and I find myself really dreading changes to the one FS I was foolish enough to use ext3 on.

It'll take some time before I trust ext4 as much as I do reiserfs.

I know it's not going to happen, but the judge and/or warden would really be doing the world a favor if they gave Hans Reiser a computer in prison and allowed him to hack on his file system.

It WILL Help

[maz2331]

Ext4 is orders of magnitude faster than Ext3 regarding fsck time. Your half-day checks will almost certainly be reduced to minutes. The developers rewrote the algorithm to not require as intensive of a search in phase 1.

If it's really important to get the machines up in minimal time (even at risk of some data loss) then you can turn off the auto checks entirely.

Re: few months for a pearl wizard

[Anonymous Coward]

and even faster for an agate necromancer...

I'm using them regularly.

[reiisi]

Not bleeding edge use, though.

Summary misses the big new feature

[Anonymous Coward]

The summary misses the big new feature of ext4... larger file and file system limits! One of the articles says the filesystem size limit for ext3 is 16TB... it is, but that's using a large block size. Using normal block size the limit is 2TB. Disks are rapidly approaching that size!

          ext4 has a 1 exabyte limit. They say ext4 "could" be extended to 64-bit block addressing later (versus the current 48-bit) if people start bumping up against that 1 exabyte limit.

Re:Why not ReiserFS?

[Anonymous Coward]

Moderators, it's not flamebait if it's true.