From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Fedyk Subject: Re: another seriously corrupt ext3 -- pesky journal Date: Mon, 18 Aug 2003 13:16:09 -0700 Message-ID: <20030818201609.GB10320@matchmail.com> References: <200308181639.h7IGdkWq019919@filer.fsl.cs.sunysb.edu> <20030818181354.GC10270@think> Mime-Version: 1.0 Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com Content-Disposition: inline In-Reply-To: <20030818181354.GC10270@think> List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: reiserfs-list@namesys.com On Mon, Aug 18, 2003 at 02:13:54PM -0400, Theodore Ts'o wrote: > On Mon, Aug 18, 2003 at 12:39:46PM -0400, Erez Zadok wrote: > > The power failure on Thursday did something evil to my ext3 file system (box > > running RH9+patches, ext3, /dev/md0, raid5 driver, 400GB f/s using 3x200GB > > IDE drives and one hot-spare). The f/s got corrupt badly and the symptoms > > are very similar to what Eddy described here: > > > > https://www.redhat.com/archives/ext3-users/2003-July/msg00015.html > > > > That is, nearly everything I try results in and error such as > > > > "Invalid argument while checking ext3 journal for /dev/md0" > > What probably happened is that the power failed while you were writing > out the inode table, and the memory failed before the DMA engine and > hard drive did, since DRAM tends to be more sensitive to voltage drops > that other parts of the system. As a result, random garbage got > scribbled all over the disk. (Ted 's observation: PC Class hardware > is sh*t.) > > Normally, this isn't a problem, since the ext3 journal contains full > backups of recently written data blocks. (As opposed to filesystems > that use soft update or logically journaled filesystems, which are > even more fragile in the face of cheap hardware that scribble random > garbage on power failure.) However, this is not true when the first After reading this comment about logical journaling (and reading a thread about htree and ext3 journaling a while ago, and how logical journaling could make the problems go away there), it made me think of reiserfs 3.6, which I have been using recently over the past six months or so. IIUC, reiserfs uses a logical journal, and it only does meta-data journaling, but not to the level of ext3's writeback mode. There are patches to add ext3-like data journaling to reiserfs that are planned to be submitted for one of the next couple 2.4-pre kernels. I'd be very interested in how reiserfs (and reiserfsck!) might handle a similar scenario. Mike