Comments on: Ext4 is now the primary filesystem on my laptop http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/ Musings about Open Source, Linux, and Life by Theodore Tso Tue, 06 Jan 2009 11:03:07 +0000 http://wordpress.org/?v=2.6.2 By: Fast ext4 fsck times | Thoughts by Ted http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-877 Fast ext4 fsck times | Thoughts by Ted Fri, 08 Aug 2008 23:33:51 +0000 http://thunk.org/tytso/blog/?p=149#comment-877 [...] filesystems generated using what was admittedly a very artificial/synthetic benchmark. During the past six weeks, though, I’ve been using ext4 on my laptop, and I’ve seen very similar [...] [...] filesystems generated using what was admittedly a very artificial/synthetic benchmark. During the past six weeks, though, I’ve been using ext4 on my laptop, and I’ve seen very similar [...]

]]> By: john http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-873 john Wed, 30 Jul 2008 19:03:22 +0000 http://thunk.org/tytso/blog/?p=149#comment-873 Ted i think you do a great job with filesystems Ted i think you do a great job with filesystems

]]> By: Justin http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-867 Justin Tue, 22 Jul 2008 15:54:20 +0000 http://thunk.org/tytso/blog/?p=149#comment-867 Hey Ted, Sorry for the off topic post, but if you could email username: Jaciss about his Google Gears comment on your Sony Reader post, that would be much appreciated. It'd be great for us non-developers to get Google Reader to sync up with the Sony Reader. Thanks, Justin Hey Ted,

Sorry for the off topic post, but if you could email username: Jaciss about his Google Gears comment on your Sony Reader post, that would be much appreciated.

It’d be great for us non-developers to get Google Reader to sync up with the Sony Reader. Thanks,

Justin

]]> By: tytso http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-858 tytso Mon, 14 Jul 2008 18:59:55 +0000 http://thunk.org/tytso/blog/?p=149#comment-858 antoszka, You raise a good point. The documentation for ext4 could definitely be better, especially as far as web pages are concerned. The ext4 wiki on kernel.org is probably the most up-to-date, but it is pretty stagnant in places. We need some help in improving the wiki; maybe you can help? In any case, I've updated the getting started page <a HREF="http://ext4.wiki.kernel.org/index.php/Ext4_Howto" rel="nofollow">here (at <b>http://ext4.wiki.kernel.org/index.php/Ext4_Howto</b>)</a> so it should be correct and up to date. If you are willing to build your own kernel you can definitely start now. We'll try to do a better job with the wiki moving forward! -- Ted antoszka,

You raise a good point. The documentation for ext4 could definitely be better, especially as far as web pages are concerned. The ext4 wiki on kernel.org is probably the most up-to-date, but it is pretty stagnant in places. We need some help in improving the wiki; maybe you can help?

In any case, I’ve updated the getting started page here (at http://ext4.wiki.kernel.org/index.php/Ext4_Howto) so it should be correct and up to date. If you are willing to build your own kernel you can definitely start now. We’ll try to do a better job with the wiki moving forward!

– Ted

]]> By: antoszka http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-857 antoszka Mon, 14 Jul 2008 16:00:25 +0000 http://thunk.org/tytso/blog/?p=149#comment-857 Dear Theodore, I'm trying to get myself updated on ext4 development every now and then (as it scratches some of my personal filesystem itches) but I'm finding it very difficult to actually dig out any useful information. Googling things like "ext4 status" gives links to ages-old blogposts by apparently unrelated people; the ext4 wiki on kernel.org seems to be plain dead, and kernel ChangeLogs only show particular atomic changes of no real meaning to a non-involved person like me. Is there a website where this stuff, along with some timeline (and related kernel releases) is summed up? I too would like to serve as a guinea pig (within reason) as soon as I read somewhere that the stuff is ready for public testing. From what I gather from the comments here, you'll have most everyday functionaly in when 2.6.27 is released and I suppose there'll be no on-disk format changes anymore. Please correct me if I'm wrong, and please let me know if there *is* a sensible source of information on this subject that I have missed. Best regards, [a] Dear Theodore,

I’m trying to get myself updated on ext4 development every now and then (as it scratches some of my personal filesystem itches) but I’m finding it very difficult to actually dig out any useful information.

Googling things like “ext4 status” gives links to ages-old blogposts by apparently unrelated people; the ext4 wiki on kernel.org seems to be plain dead, and kernel ChangeLogs only show particular atomic changes of no real meaning to a non-involved person like me.

Is there a website where this stuff, along with some timeline (and related kernel releases) is summed up? I too would like to serve as a guinea pig (within reason) as soon as I read somewhere that the stuff is ready for public testing.

From what I gather from the comments here, you’ll have most everyday functionaly in when 2.6.27 is released and I suppose there’ll be no on-disk format changes anymore. Please correct me if I’m wrong, and please let me know if there *is* a sensible source of information on this subject that I have missed.

Best regards,

[a]

]]> By: Jon Masters http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-834 Jon Masters Tue, 01 Jul 2008 03:09:20 +0000 http://thunk.org/tytso/blog/?p=149#comment-834 Coolness. I guess I might try doing the same - but probably not on my main laptop :) Jon. Coolness. I guess I might try doing the same - but probably not on my main laptop :)

Jon.

]]> By: tytso http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-833 tytso Mon, 30 Jun 2008 23:36:40 +0000 http://thunk.org/tytso/blog/?p=149#comment-833 Yoshi314, Ext4 went into the kernel early because it was designed and specified as an incremental set of improvements to ext3. Since ext3 was already in the kernel, it was already known to conform to kernel locking/coding requirements (well, the latter with some grandfather clause effect), and so we just forked the ext3 codebase to call it ext4. In fact you can mount ext3 filesystems with the ext4 code --- it is that backwards compatible. As far as readiness, portions of the code (the extent and delayed allocation code) has been used in production in Luster (clusterfs's product) for 2-3 years, and the core ext3 code is of course well-proven. How risky is it? Well, I am a bit nervous using it for my e-mail, source code, and home directory, but I am willing to risk my own data to it. As more people use it w/o problem, we'll be more confident as to its stability, but it always starts with the core developers eating their own dogfood. :-) Other filesystems that are starting from scratch do have it harder, because the barrier to entry is higher. There's no denying that. Whether this is fair or not, I don't set kernel policy; there are arguments about whether or not new device drivers (regardless of code quality) should be added to the kernel. I will note that if that adding subpar code quality device drivers is controversial, the case for subpar quality filesystems is much weaker, given that (a) if you have a certain hardware device, a new device driver is critical if you want to use it; where as we have plenty of functional filesystems, and the criticality of Yet Another Filesystem is much less, (b) a buggy device driver might lead to a crash, which can suck --- but a buggy filesystem can lead to loss of user data, which sucks far more. Yoshi314,

Ext4 went into the kernel early because it was designed and specified as an incremental set of improvements to ext3. Since ext3 was already in the kernel, it was already known to conform to kernel locking/coding requirements (well, the latter with some grandfather clause effect), and so we just forked the ext3 codebase to call it ext4. In fact you can mount ext3 filesystems with the ext4 code — it is that backwards compatible.

As far as readiness, portions of the code (the extent and delayed allocation code) has been used in production in Luster (clusterfs’s product) for 2-3 years, and the core ext3 code is of course well-proven. How risky is it? Well, I am a bit nervous using it for my e-mail, source code, and home directory, but I am willing to risk my own data to it. As more people use it w/o problem, we’ll be more confident as to its stability, but it always starts with the core developers eating their own dogfood. :-)

Other filesystems that are starting from scratch do have it harder, because the barrier to entry is higher. There’s no denying that. Whether this is fair or not, I don’t set kernel policy; there are arguments about whether or not new device drivers (regardless of code quality) should be added to the kernel. I will note that if that adding subpar code quality device drivers is controversial, the case for subpar quality filesystems is much weaker, given that (a) if you have a certain hardware device, a new device driver is critical if you want to use it; where as we have plenty of functional filesystems, and the criticality of Yet Another Filesystem is much less, (b) a buggy device driver might lead to a crash, which can suck — but a buggy filesystem can lead to loss of user data, which sucks far more.

]]> By: Omri http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-832 Omri Mon, 30 Jun 2008 21:32:45 +0000 http://thunk.org/tytso/blog/?p=149#comment-832 Indeed. By testing for production purposes I mean for the same purposes as the actual production setup, (run the same databases in the same way) but not as a candidate FS for the production setup. That's long time away. Indeed. By testing for production purposes I mean for the same purposes as the actual production setup, (run the same databases in the same way) but not as a candidate FS for the production setup. That’s long time away.

]]> By: yoshi314 http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-831 yoshi314 Mon, 30 Jun 2008 21:02:30 +0000 http://thunk.org/tytso/blog/?p=149#comment-831 i don't quite understand why ext4 made it so quickly into the kernel, while some other solutions didn't (specifically squashfs, which recently got merged or is still being planned to get merged, and of course that other famous filesystem starting with r ;-) ). how stable is ext4 as of now? i'd like to try it, but i'm not sure what are the risks right now. i don’t quite understand why ext4 made it so quickly into the kernel, while some other solutions didn’t (specifically squashfs, which recently got merged or is still being planned to get merged, and of course that other famous filesystem starting with r ;-) ).

how stable is ext4 as of now? i’d like to try it, but i’m not sure what are the risks right now.

]]> By: tytso http://thunk.org/tytso/blog/2008/06/30/ext4-is-now-the-primary-filesystem-on-my-laptop/#comment-830 tytso Mon, 30 Jun 2008 20:33:09 +0000 http://thunk.org/tytso/blog/?p=149#comment-830 Omri, By production purposes you mean, "non-critical testing", right? Ext4 is still definitely in shakedown stage, and while I appreciate people willing to serve as guinea pigs, I do get nervous when people get over-enthusiastic about using bleeding-edge code on production enterprise server machines! While getting feedback from enterprise server users/workloads is much appreciated, please don't risk your data/business on ext4 just yet. :-) Omri,

By production purposes you mean, “non-critical testing”, right? Ext4 is still definitely in shakedown stage, and while I appreciate people willing to serve as guinea pigs, I do get nervous when people get over-enthusiastic about using bleeding-edge code on production enterprise server machines! While getting feedback from enterprise server users/workloads is much appreciated, please don’t risk your data/business on ext4 just yet. :-)

]]>