On Fri, Nov 08, 2002 at 09:11:42AM +0100, Luca Berra wrote: > 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). I guess no, because the snapshot io block size is retrieved from blksize_size[][] for the underlying physical volume. Because of that we have 1024 byte for the typical disk drive unless on zSeries. > > L. > > -- > Luca Berra -- bluca@comedia.it > Communication Media & Services S.r.l. > /"\ > \ / ASCII RIBBON CAMPAIGN > X AGAINST HTML MAIL > / \ > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ -- Regards, Heinz -- The LVM Guy -- *** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them *** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Sistina Software Inc. Senior Consultant/Developer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@Sistina.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
