Red Hat Bugzilla – Bug 484330
ext3->ext4 migration doesn't enable extents
Last modified: 2009-02-20 14:03:17 EST
Per my experience, and that during the Fedora ext4 test day (https://fedoraproject.org/wiki/QA/Test_Days/2009-02-05) doing an ext3->ext4 migration doesn't enable extents on the filesystem.
This would ideally be done pre-upgrade, if possible, so that the upgraded files (which should be most of them on the root) will be created in the extents format.
I'm not sure if this sort of "pre-upgrade-migration" fits well in the anaconda flow... but it's what we'd need to do for this sort of migration to be worthwhile.
Eric - what's required to enable extents? I assume it's a tune2fs call, as with the ext2->ext3 migration.
tune2fs -O extents,uninit_bg,dir_index $DEV
fsck -pf $DEV
Is that correct? Do we also want to enable the other listed features?
Yep, it's tune2fs, and the extent[s] option (either should work) is the critical one.
dir_index should already be enabled for any recent install.
uninit_bg may be helpful, depending on how full the filesystem is, but the subsequent fsck will take a while. That one is a tossup I suppose, though you'll get better fsck times after that initial fsck. I suppose we already run fsck from anaconda pre-resize(?) so there's precedent.
The key here, though, is that unlike the ext2->ext3 migration, this needs to be done before the packages are upgraded, not after, to get any benefit from the switch to extent format.
This should be fixed in the next build of anaconda. Thanks for the info.