[linux-lvm] Reserve space for specific thin logical volumes

Gionatan Danti g.danti at assyoma.it
Tue Sep 12 22:55:37 UTC 2017

Il 13-09-2017 00:41 Zdenek Kabelac ha scritto:
> There are maybe few worthy comments - XFS is great on stanadar big
> volumes, but there used to be some hidden details when used on thinly
> provisioned volumes on older RHEL (7.0, 7.1)
> So now it depend how old distro you use (I'd probably highly recommend
> upgrade to RH7.4 if you are on RHEL based distro)


> Basically 'XFS' does not have similar 'remount-ro' on error behavior
> which 'extX' provides - but now XFS knows how to shutdown itself when
> meta/data updates starts to fail - although you may need to tune some
> 'sysfs' params to get 'ideal' behavior.

True, with a catch: with the default data=ordered option, even ext4 does 
*not* remount read only when data writeout fails. You need to use both 
"errors=remount-ro" and "data=journal" which basically nobody uses.

> Personally for smaller sized thin volumes I'd prefer 'ext4' over XFS -
> unless you demand some specific XFS feature...

Thanks for the input. So, do you run your ext4 filesystem with 
data=journal? How they behave performane-wise?


Danti Gionatan
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