[linux-lvm] Question (and feature suggestions) regarding lvmcache and lvmthin

[linux-lvm] Question (and feature suggestions) regarding lvmcache and lvmthin

[Austin S Hemmelgarn]

I've got a couple of cached LV's on my system where the origin is a 
RAID{1,10,5} LV, and have noticed that there doesn't appear to be any 
way (at least that I can find) of resyncing/scrubbing the origin LV 
without detaching it from the cache pool, which is significantly 
inconvenient as I scrub the origin LV's weekly.  I was wondering if 
there was any advice on how to do this without needing to detach it from 
the pool

On a somewhat related note, It would be a nice feature for both cached 
LV's and thinpool LV's to be able to just run 'lvchange --syncaction 
check' on the pool/cached LV and have it scrub each of the constituent 
LV's if applicable (ie, if you have a thinpool LV where the data and 
metadata LV's are RAID{1,10,5,6}, then running 'lvchange --syncaction 
check' on the thinpool would trigger a read-only resync for the data and 
metadata LV's).

Please cc me on replies, as I'm not subscribed to the list.

Re: [linux-lvm] Question (and feature suggestions) regarding lvmcache and lvmthin

[MegaBrutal]

I agree with you that these features would be nice. Actually, I also
wanted to ask for some of them. Unfortunately, I don't know about a
way to flush lvmcache without detaching and recreating the cache LV.

As a workaround you could create writethrough caches, albeit their
write performance is slower. But in that case, you'd never need to
flush the cache, as you could be sure that the origin LVs are always
up-to-date.


2015-03-06 17:29 GMT+01:00 Austin S Hemmelgarn <ahferroin7@gmail.com>:
> I've got a couple of cached LV's on my system where the origin is a
> RAID{1,10,5} LV, and have noticed that there doesn't appear to be any way
> (at least that I can find) of resyncing/scrubbing the origin LV without
> detaching it from the cache pool, which is significantly inconvenient as I
> scrub the origin LV's weekly.  I was wondering if there was any advice on
> how to do this without needing to detach it from the pool
>
> On a somewhat related note, It would be a nice feature for both cached LV's
> and thinpool LV's to be able to just run 'lvchange --syncaction check' on
> the pool/cached LV and have it scrub each of the constituent LV's if
> applicable (ie, if you have a thinpool LV where the data and metadata LV's
> are RAID{1,10,5,6}, then running 'lvchange --syncaction check' on the
> thinpool would trigger a read-only resync for the data and metadata LV's).
>
> Please cc me on replies, as I'm not subscribed to the list.
>
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