[Linux-cluster] GFS2 as virtual machine disk store

[Gionatan Danti]

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.

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