On a related note, wouldnt it be more efficient to have a single dedicated hard drive, with multiple partitions to store journals - one for each ext3 system? --- Andreas Dilger <adilger@xxxxxxxxxxxxx> wrote: > On Apr 20, 2004 23:56 -0500, Vijayan Prabhakaran > wrote: > > Is it possible to use a separate journal device > (one on a separate > > drive or a partition) shared among more than 1 > Ext3 file systems ? > > It is possible now to use an external block device > for a single filesystem. > The on-disk format is designed to allow multiple > filesystems to share the > same device, but that has never been fully > implemented. > > At one point I had implemented a patch to mount a > "jbd" filesystem with the > journal device as the first step of having a shared > journal device. Having > the "jbd" device in /etc/fstab (before filesystems > that use it) allows e2fsck > to do journal replay on all of the filesystems > before the journal starts to > be used, or alternately dumps the journal data to an > external file for later > replay (e.g. if block devices are not available when > e2fsck is run on the > jbd device). It also allows the jbd code to > configure the in-core code to > be ready for external filesystems to connect to it. > Finally, it also marks > the block device as in-use so it is less likely that > it will be overwritten > accidentally. > > See the following email for the (ancient) patch. > Most of the comments > and a large fraction of the code in that email are > still relevant, with > the exception that all of the UUID handling already > exists as libblkid > in e2fsprogs, and it doesn't say what kernel version > this is for (I'd > suspect 2.3, but I'm not totally sure. Sadly, > nobody commented on it > at the time and it was lost in the mists of > antiquity. > > > Subject: [PATCH][RFC] mountable journal devices > > To: Ext2 development mailing list > <ext2-devel@xxxxxxxxxxxxxxxxxxxxx> > > Date: Wed, 8 Aug 2001 02:08:23 -0600 (MDT) > http://marc.theaimsgroup.com/?l=ext2-devel&m=99725819513803 > > And the thread starting at discusses shared external > journal devices: > https://listman.redhat.com/archives/ext3-users/2001-November/msg00182.html > > Cheers, Andreas > -- > Andreas Dilger > http://sourceforge.net/projects/ext2resize/ > http://www-mddsp.enel.ucalgary.ca/People/adilger/ > > > _______________________________________________ > > Ext3-users@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/ext3-users __________________________________ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger. http://messenger.yahoo.com/ _______________________________________________ Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
