[linux-lvm] cache buffer size
nickey at be.mbn.or.jp
Tue Nov 5 17:29:02 UTC 2002
Thank you, Mr.Mauelshagen
JFS can not have fixed block size. But I heard from JFS group in IBM
that on 2.5 or later it will be improved. I do not know JFS will have
fixed block size or not. They said 'improved'.
I think LVM(2?) will be able to handle non-consitant block size on
"Heinz J . Mauelshagen" wrote:
> On Fri, Nov 01, 2002 at 12:07:40PM +0900, Miwako Nakai wrote:
> > I'm using jfs on lvm/raid5 with snapshot.
> > When I copy file, it happens frequently
> > 'raid5: switching cache buffer size XXX -> XXX'.
> > This message appears to syslog. It caused speed down to access disks.
> > So, I cut this message. It's seemed ok.
> Could be filesystems with different blocksizes accessing the underlying
> raid5 md through LVM constantly forcing the raid5 stripe cache to be flushed.
> If that's the case, you want to put filesystems of the _same_ blocksize
> onto all of the logical volumes allocated to the raid5 device.
> Heinz -- The LVM Guy --
> > But it's still going to switch cache buffer size. I think it cost
> > some cpu time. When switching buffer cache size, it always happen
> > reflushing memories.
> > I want to fix buffer size. What shall I do?
> > I asked JFS group. But they do nothing about cache buffer.
> > kernel 2.4.20-pre10-ac2
> > lvm 1.0.5
> > jfs 1.0.23
> > --
> > nakai at ezinc.com
> *** 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
> Mauelshagen at Sistina.com +49 2626 141200
> FAX 924446
nakai at ezinc.com
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