[linux-lvm] cache buffer size

Luca Berra bluca at comedia.it
Fri Nov 8 02:12:01 UTC 2002


On Thu, Nov 07, 2002 at 05:58:01PM +0100, Heinz J . Mauelshagen wrote:
>On Wed, Nov 06, 2002 at 11:17:05AM -0600, Steve Best wrote:
>Indeed snapshot exception table ios go by blocks of 1k.
>
>Puting the snapshot store on the same device as the original is not
>recommended in general for performance reasons.
>
>In case 1k blocks are possible with JFS:
>
>if snapshots are used regularly and there's no seperate PV to put the
>snapshot onto, you might want to create a 1k blocked jfs and try if
>that performs better than the RAID 5 stripe cache flush penalty with the 4k
>blocked filesystem.

hello,
is there any chance of having snapshots with 4k blocks for the exception
table (configurable), i want to use snapshot for backing up my root vg
but i also have swap there and it is locked to do page-sized io (4k on
ix86).

L.

-- 
Luca Berra -- bluca at comedia.it
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