I'm not sure about the following whether it may be off topic or not, but it was too interesting to read, and may also be of some interest for users on this list. there is a discussion about file systems on the gentoo list and this is an excerpt: *** Subject: Re: [gentoo-user] Gentoo 'engineers' not happy with XFS stability? From: Daniel Robbins <drobbins@gentoo.org> On Thu, 2002-09-12 at 02:32, Ian Delahorne wrote: > "Rob Harrowfield" <robboh@xtra.co.nz> writes: > > > lastly, if XFS is no longer the recommended filesystem, then whats the > > recommendation now for journalling FS's?? Resier or EXT3??? > > reiserfs has data-loss probs. Use ext3. OK, I think it's good if I summarize my experiences with the various filesystems: ext3 has been a solid filesystem for quite a long time. It also runs by default in "ordered" data/metadata mode, which means that the "data not flushed to disk" problem is nearly eliminated. It also offers a full data journaling mode to provide the ultimate in data protection. While ext3 has been pretty much solid from its inception, it's still no replacement for regular backups. Now, for ReiserFS. ReiserFS has had tons of problems in the past, up until 2.4.18. Many of these issues were not the fault of the ReiserFS developers, but were an unfortunate result of how the kernel is developed. Example: ReiserFS developers submit a patch to Linus. Linus applies their patch to a Linux kernel along with a new VFS layer that the ReiserFS developers have never seen before. Linus releases kernel without giving the ReiserFS developers the chance to test their patch with the new VFS code. As one might imagine, this tends to allow for buggy ReiserFS/VFS interactions to hit the public. To drive this point home, SuSE has never had a flaky ReiserFS implementation because they *pay* the ReiserFS developers to QA test their SuSE kernel before it is released to the public. >From 2.4.18 onwards, ReiserFS is very solid and very refined now that the kernel (in particular the VFS code) has stabilized. Filesystem corruption issues are gone. In fact, the ReiserFS dev team is receiving so few bug reports that employees responsible with tracking bugs have had to focus on other areas of ReiserFS development. However, many people are still burned by ReiserFS and refuse to use it until it has more of a track record. Personally, I am using ReiserFS exclusively on my development box, even though I've lost gigabytes of data due to flaky ReiserFS code in the past. I've been using ReiserFS for months, for *insane* things (the equivalent of maybe 50 stage3 builds on a single filesystem) with no problems or corruption or anything. My system has locked up when I've tried new experimental kernels and other weird things, and I've had no data loss issues. We have also started using ReiserFS again on chiba (gentoo.org) server and have had no issues. We store our CVS repository on it. Comparing XFS and ReiserFS, XFS has more "data loss on power off" issues. The reason appears to be that XFS still has certain areas of its code that require synchronous metadata updates. Synchronous metadata updates cause all pending metadata updates to be flushed to disk. This behavior is what made deleting files on XFS so painfully slow in XFS 1.0. With XFS 1.1, many internal synchronous metadata requirements have been eliminated, but there are still enough to trigger the "data loss on power off" problem quite often, even almost *predictably* (like *all the time, every time*) for certain patterns of IO operations. So yes, if you ignore the details, neither XFS nor ReiserFS have ordered data writes so they should both experience this problem with the same frequency and severity. In reality, however, there are certain patterns of IO operations that will cause this "data loss on power off" issue to strike with frightening regularity on XFS. In contrast, ReiserFS's out-of-order writing doesn't seem to be able to cause much if any catastrophic damage even if you're trying to trigger the problem. That's why I added the warning to the install docs. Best Regards, -- Daniel Robbins *** -- . ___ | | Irmund Thum | | _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
