Linux 3.6 Released

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Posted by samzenpus on Monday October 1, 2012 @03:00AM from the brand-new dept.

diegocg writes "Linux 3.6 has been released. It includes new features in Btrfs: subvolume quotas, quota groups and snapshot diffs (aka 'send/receive'). It also includes support for suspending to disk and memory at the same time, a TCP 'Fast Open' mode, a 'TCP small queues' feature to fight bufferbloat; support for safe swapping over NFS/NBD, better Ext4 quota support, support for the PCIe D3cold power state; and VFIO, which allows safe access from guest drivers to bare-metal host devices. Here's the full changelog."

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I Use Linux 3.6 by o5770 · 2012-10-01 03:00 · Score: 5, Funny

While the new features like quota groups, snapshot diffs and tcp "fast open" are great, what's really bothering this version is its tendency to
1. Re:I Use Linux 3.6 by Anonymous Coward · 2012-10-01 03:03 · Score: 5, Funny
  
  Completely agree. I remember when a new Linux release was about a solid, compact code base. Now it's all about optimising for specific interests even at the expense of
2. Re:I Use Linux 3.6 by larry+bagina · 2012-10-01 03:16 · Score: 3, Funny
  
  bugs TCP fast think reassemble are in I there code the
  
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3. Re:I Use Linux 3.6 by TheGratefulNet · 2012-10-01 04:17 · Score: 4, Funny
  
  come on, finish the sentence. don't leave us hang
  
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  "It is now safe to switch off your computer."
Thin clients rejoice! by Anonymous Coward · 2012-10-01 03:09 · Score: 5, Funny

Swap over NFS is something I've been waiting a long time for =)
And if you're not a fan of binary blobs by Anonymous Coward · 2012-10-01 03:15 · Score: 5, Informative

there's Linux-libre.
http://linux-libre.fsfla.org/pub/linux-libre/releases/LATEST-3.6.0/
http://en.wikipedia.org/wiki/Linux-libre
TCP Fast Open by w1z7ard · 2012-10-01 03:31 · Score: 4, Interesting

Sounds like a great feature! From the article:

"Fast Open could result in speed improvements of between 4% and 41% in the page load times on popular web sites. In this version only the client-side has been merged."

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1. Re:TCP Fast Open by Marillion · 2012-10-01 04:09 · Score: 5, Interesting
  
  On the and-user client side, there may not be much noticeable improvement. But on servers and/or load-balancing front ends this type of improvement could be quite significant.
  
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BTRFS experiences? by timeOday · 2012-10-01 03:31 · Score: 4, Interesting

I'd be interested to hear what uses people have found for the advanced features of BTRFS. (BTRFS snapshots on a RAID1 volume seem like a great /home partition?) Since BTRFS is gradually evolving it's kind of hard to get a grasp of what is currently available and trustworthy (although this approach is vastly preferable to Microsoft's approach to revolutionizing the filesystem - aim high and never deliver!)
1. Re:BTRFS experiences? by mcelrath · 2012-10-01 05:53 · Score: 5, Informative
  
  I've been using btrfs on two computers for about a year now. I'd say it's quite stable. I'm using it for /home as well as a data partition, with zlib compression on /home. The snapshot feature is amazing and should be used liberally. Early on I experienced some disk corruption (mostly due to rapidly switching kernel versions 3.0, 3.2, 3.4, 3.5), which was not a problem because there existed snapshots on the disk. The primary partition can be corrupted, but if you have an uncorrupted snapshot, you can mount it. So, it's a good idea to get in the habit of making regular snapshots. I've been doing it by hand, but a daily rotating snapshots would be a great idea for reliability. There are many cron jobs, shell scripts and whatnot to accomplish this (e.g. Autosnap). Furthermore there is apt-btrfs-snapshot which on Debian/Ubuntu systems will automatically snapshot whenever upgrading/installing a package. This basically takes care of changes in /usr (and you'll need a cron job for /home). The only real drawback I've encountered is that dpkg is very slow (likely due to my use of zlib compression). But dpkg's database access has been a snail for a long time and is dpkg's problem (and I hope someone looks into this soon, it's pissing me off -- zlib just exacerbates the problem). But since apt-get upgrade can run in the background while I'm working, it doesn't really bother me.
  I'm also using RAID1 on all magnetic disks (plus one SSD not in a RAID configuration). After countless disk failures, I just don't trust magnetic disks any further than I can throw them. And, they are cheap enough that two instead of one is not a huge burden. In the last year, I have not had occasion to recover from a failure due to RAID1, but I have experimented with mounting one half of the RAID1, and it operates normally. There are a few tricks to re-sync the drives when its partner is re-added to the array, that one should be aware of. It's not fully automatic. One of my RAID1 arrays is over two LVM volumes, with the left half consisting of a single 3 TB disk, and the right half consisting of three disks concatenated into a single LVM. This makes it easier to add disks later. LVM and btrfs can both resize.
  A couple things to be aware of: you cannot place a swap file on a btrfs partition. So use another filesystem, a full partition, or just buy more RAM (my preferred solution). You should not use a kernel version less than 3.5. There have been many fixes between 3.0 and 3.4, and you're asking for trouble if you use btrfs on a 3.0 or 3.2 kernel. Since I installed 3.5 kernels on all my machines, I have not had any btrfs-related problems. FWIW, I regularly have to reboot because ATI's shitty video driver causes a kernel panic, sometimes via a hard reset. I have yet to see any filesystem corruption due to this. And everyone should know how to use the Magic SysRq key in the event of kernel panics too. (Alt-SysRq- REIUSB should unmount, sync, and boot, leaving filesystems in a consistent state)
  I highly recommend BTRFS at this point. I'm not sure the distributions are up to noob auto-installs, but if you like to do things yourself, it offers a lot of advantages over ext4.
  
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2. Re:BTRFS experiences? by flok · 2012-10-01 05:55 · Score: 4, Informative
  
  If you have LVM underneath the ext4 filesystem, you can indeed randomly grow the fs.
  
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3. Re:BTRFS experiences? by Rich0 · 2012-10-01 07:27 · Score: 3, Interesting
  
  Sure, if you don't mind it being a pain to dynamically reallocate space between all your filesystems.
  Oh, can you copy a 300GB file full of data in a few milliseconds and have the copy only occupy the space necessary to capture the differences between them? No, I don't want a hard link - I want changes to either file to not affect the other.
  You can also instantly snapshot files, directories, or the entire filesystem, and the snapshots are first-class citizens (they can be modified, be used in place of the originals, etc).
  Oh, and if the power dies in the middle of writing a RAID stripe you don't lose anything beyond the changes to the files you were intending to modify.
  Btrfs will be the standard filesystem on linux in a few years - nobody really doubts that. Its main issue now is that it is still fairly immature.
4. Re:BTRFS experiences? by Bengie · 2012-10-01 07:42 · Score: 3, Interesting
  
  I know I tend to play Devil's advocate in an almost trollish way, but it invokes great responses like your's and bluefoxlucid. It seems if you don't get people defensive on the internet, they tend to ignore your posts and don't reply with potentially great stuff.
  
  Anyway, I didn't know about LVM and it looks quite "great". One question I have about it is that it supports allowing a volume to have a RAID1 style backing. If some of the data got silently corrupted in one of the mirrors, how would EXT4 decide which data to choose and how would it fix it or does LVM do this?
  
  The biggest logical issue I've seen with separating volume managers from the FS is that the two typically don't communicate. This lack of communication hurts the overall resiliency. Not to say the FS and volume manager couldn't communicate via an API or something.
Re:The consumers want to know by smooth+wombat · 2012-10-01 03:38 · Score: 4, Insightful

So no one important.

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Mostly about btrfs by javilon · 2012-10-01 03:41 · Score: 3, Interesting

The most active area seems to be btrfs. What is the general opinion, is it ready for general usage?
Any one with feedback from production setups?

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1. Re:Mostly about btrfs by mlts · 2012-10-01 04:09 · Score: 3, Interesting
  
  btrfs is coming along, but most distros still tend to have ext4 as a default. The one thing that btrfs really and desperately needs is filesystem deduplication. Even Windows now has that in place (although it is of a delayed variety where a background task searches for identical blocks and replaces the copies with pointers.)
2. Re:Mostly about btrfs by bluefoxlucid · 2012-10-01 05:08 · Score: 3, Informative
  
  Because you have people like me who say, "What we should do for deduplication is hash blocks and keep them in a fast bucket hash table cached in RAM and pointed to in the block index. Then we can occasionally compare identically-hashed pointers to see if the blocks are the same, and if so drop one or the other pointer and repoint the others. This dropping can be done by selecting the one with the highest use count as our new pointer, and altering old pointers as they're accessed rather than actively, until the duplicate pointer is empty." Someone says, "PATENTED ALREADY LOL!" It's not "I patented data dedup," it's "Here's every way I can think of to do it, PATENT NOW! Oh you did something vaguely similar to this one, that's mine..."
  
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3. Re:Mostly about btrfs by Bengie · 2012-10-01 05:33 · Score: 3, Informative
  
  Any transactional FS(ZFS/BTRFS) shouldn't need fsck. You always start from the last commited transaction or snapshot.
Re:The consumers want to know by Anonymous Coward · 2012-10-01 04:45 · Score: 4, Informative

It was some fine Tuesday back in 2008-09. Why do you ask?
Re:Ok, ok, question by hduff · 2012-10-01 05:06 · Score: 3, Insightful

As a Linux noob, how do I learn what all of those words mean? The only one I even vaguely recognize is TCP and i don't even know what that is. Until someone responds, I'll be at Google.
Which is how it is done.

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Re:Ok, ok, question by jones_supa · 2012-10-01 05:10 · Score: 4, Informative

Try kernelnewbies.org and Wikipedia also.
Re:Ok, ok, question by Lennie · 2012-10-01 05:25 · Score: 3, Informative

You might want this page then:
http://kernelnewbies.org/Linux_3.6
It usually has links to http://www.h-online.com/ http://lwn.net/ and/or Wikipedia which hopefully explains it in a way you'll understand.

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Sounds like Windows' IIS by PhrostyMcByte · 2012-10-01 05:53 · Score: 4, Interesting

This sounds a bit like they generalized the clever latency-saving behavior of IE which skips the TCP handshake when talking to IIS and leaves connections half-open. Latency could indeed be greatly improved for servers supporting it.
Re:Ok, ok, question by hobarrera · 2012-10-01 06:08 · Score: 3, Insightful

Most of these words are not linux-specific, though they are rather technical. It's what you'd expect on the release of a new kernel version, especially on slashdot.
Re:Please explain by Metabolife · 2012-10-01 06:10 · Score: 5, Funny

It's really quite simple. The parent and grandparent are simply implying that
Re:Please explain by sgage · 2012-10-01 08:11 · Score: 5, Funny

There once was a man from Lahore,
whose limericks stopped at line four.
When asked why this was,
he said just because
Re:Comparison by MtHuurne · 2012-10-01 09:02 · Score: 3, Insightful

There is a new Linux kernel release every two months; Ask Woz is a once in 15 years event.
Re:Still no TRIM on software RAID (md) by Mad+Merlin · 2012-10-01 09:58 · Score: 3, Informative

Support for TRIM on RAID linear/0/1/10 md devices was quite recently added. The patch series is here: https://lkml.org/lkml/2012/3/11/261. I can't find the actual merge now, but I believe it'll be in 3.7.

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