And another one ... > Hi, > > The attached patch (code only) adds support for external log devices for > XFS and ext3/4 to setup-storage. > > External log devices can improve performance a lot when they reside on a > different physical device than the filesystem itself. >
Ok. > Due to the way mkfs commands are ordered in setup-storage, the commands > fire as soon as possible, so the mkfs command can run before all the > physical devices have been partitioned, make it impossible to just use > createargs to enable an external log device. > > There are two approaches to this issue: > - delay all mkfs commands until all the devices have been set up > (physical devices, RAID, LVM, cryptsetup ...) > - integrate external journals into setup-storage > > I went with the latter because the former requires more profound changes > in setup-storage and I think it's not worth it/better this way. > I fully concur - I believe the first approach would be a really really ugly hack. Parsing createopts is really something I'd like to avoid... > If the patch is accepted, I'll resend a patch including documentation. > > Config example: > > disk_config /dev/sda fstabkey:uuid > primary - 256 ext3_journal - > primary - 256 ext4_journal - > primary - 256 xfs_journal - > logical / 2000 ext4:journal=/dev/sda2 defaults > logical /home 2000 xfs:journal=/dev/sda3 defaults > > disk_config /dev/sdb fstabkey:uuid > primary /foo 10- ext3:journal=/dev/sda1 defaults > > > Thoughts? [...] Hmm, the _journal stuff feels a bit like a hack. Couldn't one just have "-" or ext4 in there and say "-O journal_dev" in createopts? Arguably, that requires a bit more typing, but the code to process the _journal entries feels hackish. It requires a lot of special-casing... Best, Michael
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