Hi, Am Dienstag, 14. Juli 2020 18:05 CEST, schrieb David Teigland <teigland@xxxxxxxxxx>: > On Mon, Jul 13, 2020 at 04:34:52PM +0200, Janne Heß wrote: > > However some of my systems are single-disk systems. For those, RAIDs are > > not possible so I was thinking if LVM has some support for single-PV > > setups with parity on the same PV. > > Hi, > > We didn't include integrity+linear because we didn't see much value in it, > since it would require going to backups in case of an integrity failure. > > > While this is probably a niche feature right now, I can see other > > projects like Stratis benefit from the integrity checks provided by > > dm-integrity (and dm-crypt in the future) to detect (and thanks to > > parity fix) bit rots. > > dm-integrity will detect but not fix bit rot. This is where I see a benefit from having some parity on the LVM level. With dm-integrity spotting bit-rots and reporting errors to LVM, LVM can recover the blocks with parity information. This recovery procedure would give more feature parity to ZFS which I'm currently migrating from for a LVM-based solution. > > > So is there any way to get a parity setup with the current state of LVM? > > I was thinking of a RAID-4 with one PV but the current tooling (more > > specifically lvcreate) doesn't let me do that. > > It's not currently possible. We had an implementation for this we could > bring back if there is enough interest, so we'd like to hear more about > how this would be useful for you and others. I think this would be beneficial for a lot of users since it allows spotting and correcting bit-rots which is currently not possible other than using ZFS or RAID as far as I know. > > Thanks, > Dave > > _______________________________________________ > linux-lvm mailing list > linux-lvm@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > Thanks, Janne _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
