Dne 15.5.2017 v 16:48 Gionatan Danti napsal(a):
On 15/05/2017 14:50, Zdenek Kabelac wrote> Hi
What I does not understand is how XFS and EXT4 differs when a thinp is full.
From a previous your reply, after I asked how to put thinp in read only mode
when full:
"Using 'ext4' with remount-ro is fairly easy to setup and get exactly this
logic."
My naive interpretation is that when EXT4 detects *any* I/O error, it will set
the filesystem in read-only mode. Except that my tests show that only failed
*metadata* update put the filesystem in this state. The bad thingh is that,
when not using "remount-ro", even failed metadata updates will *not* trigger
any read-only response.
Ever tested this:
mount -o errors=remount-ro,data=journal ?
Everything has it's price - you want to have also 'safe' data - well you have
to pay the price.
On the other hand, XFS has not such options but it, by default, ensures that
failed *metadata* updates will stop the filesystem. Even reads are not allowed
(to regain read access, you need to repair the filesystem or mount it with
"ro,norecovery").
So, it should be even safer than EXT4, right? Or do you feel that is the other
way around? If so, why?
I prefer 'remount-ro' as the FS is still at least accessible/usable in some way.
Things are getting better - but planning usage of thin-pool to 'recover'
overfilled pool is simple BAD planning. You should plan your thin-pool usage
to NOT run out-of-space.
Sure, and I am *not* planning for it. But as bad things always happen, I'm
preparing for them ;)
When you have extra space you can add for recovery - it's usually easy.
But you will have much harder time doing recovery without extra space.
So again - all has its price....
Regards
Zdenek
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
