[linux-lvm] howto cache a thinpool-device?

[linux-lvm] howto cache a thinpool-device?

[Oliver Rath]

Hi list,

Im playing around with the new cache options. Ive created a lvm-device
on my cache-disk named lvx-cache (vg is dmivg). Additionally Ive created
a thinpool-device named winthinpool.

Now i wanted to use my cache-device to cache my thinpool-lvm, but this
doesnt work:

~# lvconvert --type cache --cachepool dmivg/lvx_cache dmivg/winthinpool
  Can't cache thin-pool volume dmivg/winthinpool.

isnt is possible to cache a thinpool-device?

Tfh!
Oliver

Re: [linux-lvm] howto cache a thinpool-device?

[Oliver Rath]

Hi list,

what now worked:

- creating a cached data-lv
- creating a non-cached meta-lv
- converting data-lv to a thinpool-device with meta-lv as metadata

what not: doing the same thing with a cached meta-lv. Does this make sense?

Is the metadata already cached by lvm-logic? Do i have a cache thinpool
(with non-cached metadata) with the used way?

Tfh!
Oliver


Am 09.08.2014 um 15:43 schrieb Oliver Rath:
> Hi list,
>
> Im playing around with the new cache options. Ive created a lvm-device
> on my cache-disk named lvx-cache (vg is dmivg). Additionally Ive created
> a thinpool-device named winthinpool.
>
> Now i wanted to use my cache-device to cache my thinpool-lvm, but this
> doesnt work:
>
> ~# lvconvert --type cache --cachepool dmivg/lvx_cache dmivg/winthinpool
>   Can't cache thin-pool volume dmivg/winthinpool.
>
> isnt is possible to cache a thinpool-device?
>
> Tfh!
> Oliver
>
> _______________________________________________
> 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/

Re: [linux-lvm] howto cache a thinpool-device?

[Brassow Jonathan]

If it was me, I would put the thinMetaLV directly on the fast device (because it is small) and I would cache the thinDataLV.

Remember that some of what you are doing is pretty cutting edge.  I wouldn't yet use caching + thin in production yet.

Also, consider making your thin devices redundant (if they are not already via backend storage).

 brassow


On Aug 9, 2014, at 11:26 AM, Oliver Rath wrote:

> Hi list,
> 
> what now worked:
> 
> - creating a cached data-lv
> - creating a non-cached meta-lv
> - converting data-lv to a thinpool-device with meta-lv as metadata
> 
> what not: doing the same thing with a cached meta-lv. Does this make sense?
> 
> Is the metadata already cached by lvm-logic? Do i have a cache thinpool
> (with non-cached metadata) with the used way?
> 
> Tfh!
> Oliver
> 
> 
> Am 09.08.2014 um 15:43 schrieb Oliver Rath:
>> Hi list,
>> 
>> Im playing around with the new cache options. Ive created a lvm-device
>> on my cache-disk named lvx-cache (vg is dmivg). Additionally Ive created
>> a thinpool-device named winthinpool.
>> 
>> Now i wanted to use my cache-device to cache my thinpool-lvm, but this
>> doesnt work:
>> 
>> ~# lvconvert --type cache --cachepool dmivg/lvx_cache dmivg/winthinpool
>>  Can't cache thin-pool volume dmivg/winthinpool.
>> 
>> isnt is possible to cache a thinpool-device?
>> 
>> Tfh!
>> Oliver
>> 
>> _______________________________________________
>> 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/
> 
> _______________________________________________
> 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/