thanks for the feedback in previous older versions of LVM, I guess that each lv requires a minor, major and these are might have limitations of how many can be addressed but how about LVM2? if I intend to have many hundred thousands of LV, would that be any issue? Sent from my iPhone > On 1 Sep 2020, at 15:21, Gionatan Danti <g.danti@xxxxxxxxxx> wrote: > > Il 2020-08-30 21:30 Zdenek Kabelac ha scritto: >> Hi >> Lvm2 has only ascii metadata (so basically what is stored in >> /etc/lvm/archive is the same as in PV header metadata area - >> just without spaces and some comments) >> And while this is great for manual recovery, it's not >> very efficient in storing larger number of LVs - there basically >> some sort of DB attemp would likely be needed. >> So far however there was no real worthy use case - so safety >> for recovery scenarios wins ATM. > > Yes, I agree. > >> Thin - just like any other LV takes some 'space' - so if you want >> to go with higher amount - you need to specify bigger metadata areas >> to be able to store such large lvm2 metadata. >> There is probably not a big issue with lots of thin LVs in thin-pool as long >> as user doesn't need to have them active at the same time. Due to a nature of >> kernel metadata handling, the larger amount of active thin LVs from >> the same thin-pool v1 may start to compete for the locking when >> allocating thin pool chunks thus killing performance - so here is >> rather better to stay in some 'tens' of actively provisioning thin >> volumes when the 'performance' is factor. > > Interesting. > >> Worth to note there is fixed strict limit of the ~16GiB maximum >> thin-pool kernel metadata size - which surely can be exhausted - >> mapping holds info about bTree mappings and sharing chunks between >> devices.... > > Yes, I know about this specific limitation. > > Thanks. > > -- > Danti Gionatan > Supporto Tecnico > Assyoma S.r.l. - www.assyoma.it > email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx > GPG public key ID: FF5F32A8 _______________________________________________ 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/
