Il 29-08-2017 12:59 Steven Whitehouse ha scritto:
Yes, it definitely needs to be set to cache=none mode. Barrier passing is only one issue, and as you say it is down to the cache coherency, since the block layer is not aware of the caching requirements of the upper layers in this case.
Ok. Sorry to be pedantic, but I would be sure to grasp it: using cache=writeback will *not* cause data corruption, rather low performance if/when the cache coherency protocol is needed (ie: when live migrate a VM from first to second host), correct?
It will depend a great deal on a number of factors... the performance of the storage and also the number of inodes on the filesystem. It will also take longer if there is any work to do (i.e. if changes need to be made compared with just checking an otherwise clean filesystem) so it is difficult to give any guidance without knowing those variables. The best way to know is to try it and see, Steve.
Ok, so some first-hand testing will be needed. Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx GPG public key ID: FF5F32A8 -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
