Slashdot Mirror
How To Move Your Linux Systems To ext4
LinucksGirl writes "Ext4 is the latest in a long line of Linux file systems, and it's likely to be as important and popular as its predecessors. As a Linux system administrator, you should be aware of the advantages, disadvantages, and basic steps for migrating to ext4. This article explains when to adopt ext4, how to adapt traditional file system maintenance tool usage to ext4, and how to get the most out of the file system."
reiser4?
IranAir Flight 655 never forget!
"largely unnoticed by mere mortal Linux users and administrators" strikes me as a strange phrase to find on this IBM page. Is there some other IBM project more interesting than ext4 being revealed here?
The only change I can believe in is what I find in my couch cushions.
ext4fs is designed to be used in systems requiring many terabytes of storage and vast directory trees. It is unlikely the common desktop (or even, for that matter, the common server) will see appreciable performance increase with it.
Link to Ext4 entry on Wikipedia for people who aren't familar with it (like me).
Partition, partition, partition.
Yes, Terabyte is not entirely correct according to SI, but Tebibyte just sounds lame and language is a tool, to facilitate written and oral communication.
Of course, in this case you have to balance the confusion stemming from the Tera in IT context meaning 1024 in some cases. To be honest, people insisting on the new naming, they should have come up with a sensible sounding name and promoted that. You have to remember that language, even technical language is for the people. There are lots of ways to craft a beautiful, logical, symmetrical language that no sane person would use because it just doesn't sound convenient.
Maybe a linguist can pitch in to explain why tebibyte sounds so awful?
It takes a man to suffer ignorance and smile
Be yourself no matter what they say
Did you see the section on timestamps? Nanosecond resolution out to 2514.
Nanoseconds.
We're dealing with a process whose maximum useful precision is "has the green light gone off yet", and we've got nanosecond timestamps.
Yahoo! Pipes are awesome. How awesome? http://pipes.yahoo.com/jesdynf/slashdot
...who are on the lookout for a new fs to entrust with keeping their precious data: make sure to check out btrfs ( http://oss.oracle.com/projects/btrfs/ ). It's a really neatly spec'd filesystem (with all the zfsish stuff like data checksumming and so on), developed by Oracle employees under GPLv2, which will feature a converter application for ext3's on-disk-format - so you can migrate from ext3 to the much more feature-packed and modern btrfs without having to mkfs anew.
On a related sidenode: I'm very happy with SGI's xfs right now. ext\d isn't the only player in the field, so please, go out and boldly evaluate available alternatives. You won't be disappointed, I promise.
:%s/Open Source/Free Software/g
YTARY!
Step 1: Install Fedora 9
OK, all done!
Oh, please. ext2 had "undelete" capability, just as it had filesystem compression capability. Neither were ever implemented.
Hail Eris, full of mischief...
E pluribus sanguinem
Buy a Mac and use OS X, then you won't have to worry about this kind of shit.
THINK DIFFERENT. THINK BETTER. THINK APPLE!
Personally, I think the whole thing is a mess, and computer professionals should be working harder to enforce a consistent scheme. Unfortunately, only a minority of computer professionals seem interested in changing the status quo confusion. Maybe a linguist can pitch in to explain why tebibyte sounds so awful? I'm no linguist, but I don't think "Tebibyte" sounding silly is the real problem. I admit that I laughed when I first heard the binary prefixes. They sound lame. But who cares? "Quark" was silly when it was first coined. So was "Yahoo" and "Google" and "Linux" and "WYSIWYG" and "SCSI" and "Drupal" and so on... Silly names become second-nature once they are used enough.
I think the real problem is that people, inherently, are loathe to change. They are more apt to come up with rationalizations and justifications for doing things "the old way" rather than put in the work to learn (and code!) a new system. Sorry if this sounds harsh, but I find the people who say the binary prefixes "sound dumb" or say that "the current (inconsistent)* system works fine" are just coming up with excuses to avoid doing the work to use a properly consistent standard/notation.
Maybe you're right, and that if the new prefixes had sounded "cooler", then adoption would have been faster... but I'm not so sure. Even if true, it doesn't absolve any of us for allowing the confusion to persist: cool or not, we (geeks especially!) should have the discipline to use proper standards.
* The current system can be roughly described as: SI prefixes are powers of 10 everywhere except in computer science, when they become powers of 2. But only when referring to memory, and some data structure sizes, but not when referring to transmission rates or disk space (unless it's a flash drive, sometimes), and other kinds of data structures.
That's all fine and dandy, but will it allow me to somehow undelete/recover when I accidently type rm -Rf /hugedir -- yes I know there are other ways to delete stuff, I just find it ridiculous that all linux file systems with the exception of ext2 make no effort at all to be able to recover from such a common mistake.
Of course, rm not giving any indication at all about how many bytes and files it is about to remove doesn't help either.
Entrepreneur : (noun), French for "unemployed"
1024^4 television shows and not one of them worth watching.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Might I recommend passing the -I option? I have rm aliased to 'rm -I' on my work machine.
--"insert clever quote here"
I think you're looking for rm -rI /hugedir then. Adding the -f option is you specificly stating that you know exactly what you're doing and do not want to be asked if you're sure you want to remove /home and all it's subdirectories.
Violence is like duct tape. If it doesn't solve the problem, you didn't use enough.
Maybe it's your accent? I'm entirely serious. I don't have trouble saying either word, or find an aesthetic difference.
So, what's your accent? This is bemusing. You've got me trying the words in various regional intonations to figure out why you find tebibyte a bad coinage. No luck so far.
ext4 is the biggest waste of time and effort in Linux. There are already good extent based filesystems for Linux. Why anyone would consider using what is an experimental filesystem for a multi TB production filesystem is beyond me.
What ever they do XFS and JFS will have way more testing and use than ext4 will ever have. I just don't get the point of ext4. It would be far more useful to fix the one remaining issue with XFS, the inability to shrink the filesystem none destructively, than to flog the dead horse which is ext2/3 even more with ext4, which is not one disk compatible anyway.
Wouldn't it be easier to make manufacturers use the old MB=1024 type standard than to get the common people to understand a new prefix that they just won't remember?
Once you start despising the jerks, you become one.
Comment removed based on user account deletion
Those features may be new to ext3, but not to the real competitors. I see nothing that might grant an edge over JFS or XFS. The real justifications will come from performance tests.
This reminds me of the recent NTFS article here, which actually suggested that since Hans Reiser is in jail and reiser4 is dead, we should consider NTFS. WTF? The ludicrousness of using NTFS as the primary filesystem is further justified in this article by its similar performance to ZFS, but both run in user-space (and are thus horrible in performance), so neither is really an option. What the heck is wrong with JFS and XFS?
Here are some real comparisons: First, Wikipedia's Comparison of file systems gets you started with a nice mapping of features. Second, a benchmarking of filesystems from 2006 which is still quite applicable (though it doesn't yet cover ext4). What we need is a comparison of EXT4 to XFS and JFS (et al), with EXT2/3 in there for reference.
Recall that the biggest reason for using ext3 is that it is supported best of all the filesystems. If all hell breaks loose, even Tomsrtbt (an ancient rescue floppy pre-dating knoppix) can fix it. Ext4 breaks this backwards-compatibility to ext2. Therefore, I see no reason to use it. One might as well use something more stable and proven, especially while we lack numbers suggesting it performs as well or better.
Use my userscript to add story images to Slashdot. There's no going back.
Now that OpenSolaris is out... Use a REAL UNIX.
My favorite file-system reportedly performed faster on certain workloads if it was compressed. However the primary maintainer will be incarcerated for a very long time.
Dose EXT4 (or EXT3 for that matter) support running as a compressed file-system? If so, what is the speed like?
Especially on that workload most likely to benefit substantially from running as a compressed file system. Mid to High Traffic Email server.
--= Isn't it surprising how badly I spell ?
ok, I'll agree ext4 blows.. XFS and Jfs are dogs in the small file arena. sure they both address it, but neither one does it well. nor do they have undelete, which is pretty nice. and one second file timing is a bit on the loose side, especially if your running a batch that checks that sort of thing. And none of these are tuned for a SSD at all. So yes we need upgrades, big time, ext4 isnt it..
If you want undelete capabilities, maybe rm just isn't right for you. You could just make rm an alias to "mv $1 ~/.trash/" or something?
Anyone know an easy way to convert from Reiser? I set up a Reiser partition a while back. It's quite large. I think I'd need to do it peacemeal, like, size reiser partition down, create ext3.. move files.. size it down again, increase size for ext3, etc.. until the reiserfs has no space on it?
I don't have the space to unload all the reiser files someplace else.
Any ideas? Does gparted resize reiserfs without destroying the fs?
The article doesn't say this explicitly enough: if you like to keep your data, DON'T USE EXT4 YET! It is still in highly experimental stage. Try it out, fine... but not as the only copy of your data.
I've been bitten by the ext3 journal corruption bug due to out-of-order writes of the journal (write-heavy operation on a large RAID with write-back caching and a power failure), so... how well is journaling and recovery being tested under such conditions?
thegodmovie.com - watch it
...flushes the free space left on its array.
Violence is the last refuge of the incompetent. Polar Scope Align for iOS
There are three problems with such a simple solution; I talk about them above. (Ignore the first two; they don't apply. The third/fifth is in a reply to that post.)
Anybody who advocates NTFS has never worked with directories with a large number (>100,000) of files under one directory tree. Just deleting one file can make the disk seek for several seconds, during which the filesystem is completely frozen. I guess it's reshuffling its entire B-tree.
thegodmovie.com - watch it
Comment removed based on user account deletion
One of the new features is checksums for the journal. That alone should make it the filesystem of choice for everyone. After all, what good is a filesystem which will pass you faulty data and pretend everything's fine.
BTW, is there a filesystem which maintains checksums for all data? I've had hard to detect problems with faulty hardware, because the error rate was very low, and to this day I don't know what data was corrupted because there were no checksums on most of the data.
Yeah, but now the problem is that KB is now ambiguous - it could either be 1000 bytes, or it could be 1024. Before anyone mentions HDD manufacturers, it isn't ambiguous there, either. 1 KB is 1000 bytes, yeah that's because they're fleecing you, it sucks but oh well.
What if we CS geeks agree to write 56Kb<sub>2</sub>? If it's conversational, no need.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
and that is the problem.
Colorless green Cthulhu waits dreaming furiously.
Better watch that around these activists. They're a peaceful bunch, but don't even think about drawing on them, especially if you only have six shots.
Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
What I was hoping for was some improvements in making use of the characteristics of SSDs. But maybe that'd have to be an entirely new filesystem that is not designed with seek time as a generic assumption. Any takers? -Lars
I know you're trolling but OS X is slowly going to get rid of HFS+ in favor of Sun's ZFS. Soon you will have the option to migrate your current Mac file system to ZFS. What are the benefits? What are the downsides? Hopefully there will be an article on Slashdot to help you with that.
BTW, this post was written on a Mac. Evangelizing the OS X platform is fine as long as you do it for the right reasons. Doing it the wrong way or for the wrong reasons make us all look bad. Open Source advocacy is the same way.
The ext3 file system is pretty much OK, ext4 is only tweaking functionality.
RAID on Linux handled by the MD subsystem, which is largely cluster unaware. This means it's unsafe for example to stripe across multiple iSCSI devices then run a cluster file system like GFS on top, which also therefore means that you have to have hardware RAID on a per device basis.
Deleted
Have the "trash-instead-of-rm" script md5sum the "deleted" file and rename it to ~/.Trash/.. If you get clashes it's very likely to be an identical file anyway and you avoid the various issues that might crop up if you try to recreate directory structures in ~/.Trash.
This might need a fair bit of cpu on very large files (anything below a few MB is trivial on modern CPUs), but then you probably don't want to keep very large files lying around in ~/.Trash anyway (prevents good block allocation by the file system), so you could just opt to delete those immediately.
HAND.
Now I'm sure that Sturgeon is to blame for Nina's murder in a corporate conspiracy to finish off Reiser4.
:-)
Phew, Sean... 9 kills, just 1 more for RAMPAGE!
Or is it multi-kill, sorry, haven't played UT in ages.
...when on April 26, 2514, at 12:01 PM a lonely hacker decides to boot up the box he found buried in his backyard - big letters on it: "Linux, Ext4 install". He only heard of "Linux" once, but never anything on "Ext4", and is immensely interested in seeing what the thing would do. Some old history patch (a patch is a millimeter thick/wide data carrier) contains information on the voltage of the time and how one could produce it using a solar array. So he puts his solar area (1 centimeter in diameter) in his room, and as the light of the room powers the solar array connects the box to the solar array powered converter providing 120V. Doing some further hacking he converts the "DVI"-output of the thing to his wallscreen's 1024bit-digital input, and presses the On-button.
Momentarily, the system boots, starts counting "Bogomips" and generally makes the hacker feel like he found something of immense value. Now he will know everything on the old "Linux" operating system, which is so hard to locate or read on now B.G. Inc. has taken over governmental control of the former USA, and renamed the capitol "1 B.G. Way", and the whitehouse "Microhouse (c) MS". Then something happens, a message : "Kernel panic, init not found !", and the thing crashes..
I tell you, how do we explain to that hacker, more than 500 years away, that EXT4 was simply not made to run beyond April 25, 2514 ? Unacceptable, failure waiting to happen: think of the poor future hackers in a dystopian society!
Slashdot: stuff for news, nerds that matter, matter for news, stuff that nerd
By then, the onboard battery will already have failed, and data will be restored to January 1st 1970.
Rethinking email
Comment removed based on user account deletion