Gluster users - May 2016 - Questions about healing

>    Anyway how is possible to keep VM up and running when healing is
happening
>    on a shard? That part of disk image is not accessible and thus the VM
>    could have some issue on a filesystem.
Yeah, but healing a few MB shard takes a few second, so the VM is frozen for a
very small
amount of time. Without sharding, the VM is frozen as long as the whole disk
hasn't
been healed, which will take hours on big clusters.

-- 
Kevin Lemonnier
PGP Fingerprint : 89A5 2283 04A0 E6E9 0111
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Il 21 mag 2016 08:38, "Kevin Lemonnier" <lemonnierk at
ulrar.net> ha scritto:
> Yeah, but healing a few MB shard takes a few second, so the VM is frozen
for a very small
> amount of time. Without sharding, the VM is frozen as long as the whole
disk hasn't
> been healed, which will take hours on big clusters.
Which is the OS reaction to a locked storage?  It's transparent or could
lead to FS issue?
What would happen if healing starts in the middle of a write, for example
when MySQL flush to disks?

Let's assume a 100gb image sharded (10mb) in a replica 3 on a 3 nodes
cluster
the image is split in 10.000 pieces, stored in all servers (replica 3)
If a server goes down, the whole VM needs to be healed , thus the whole vm
is locked

Shard is useful on single brick failures, that could be avoided by using
raid, non for server failure
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