Re: [linux-lvm] LVM System

["Anthony W. Marino" <anthony@AWMObjects.com>]

On Monday 04 March 2002 06:53 pm, Austin Gonyou wrote:
> On Mon, 2002-03-04 at 17:39, Steve Wray wrote:
> > I'd recommend ext3 with data journalling for sensitive
> > filesystems. Its slower than XFS but (seems to) scale better with
> > striping and large files. XFS performance (seems to) fall off
> > very rapidly as file size exceeds buffer size.
> >
> > XFS only journals metadata. So on event of a crash,
> > the filesystem structure will (likely) be sound, but theres
> > no guarantee that the data blocks will be uncorrupted!!!
> >
> > XFS is very nice tho, in that volumes and filesystems can
> > be grown with no downtime at all (without even unmounting).
> >
> > You might want to do some benchmarking before committing
> > to a build (thats recently saved my butt actually).
>
> I've only got a couple of things to say in the regard about XFS and
> performance Falling off.
>
> XFS's performance doesn't fall off in the respects you've spoken about.
> It's a misconception when using LVM, or evms, etc along with XFS.
>
> I ran into a similar issue, and was convinced it was XFS or LVM, etc.
> This is in the relation of using XFS and LVM, vs. XFS with no LVM, and
> then testing increasing filesizes with iozone.
>
> What I found was that dbench, and iozone both did not perform very well
> with respect to software raid or striping, but that in fact the
> filesystems themselves performed about 100% faster than without LVM
> striping or LVM Concat.
>
> So much faster that my database guys noticed the enourmous increase in
> speed on a test setup I created for them. One was using LVM, one was
> not, with XFS. The one which was NOT using LVM had a hardware stripe
> setup with write-back caching and adaptive read-ahead. The controller
> has 128MB pc100Dimm. Using a 3 drive RAID 0 hardware, vs 3 drives
> striped with LVM was an enourmous downgrade when benchmarking..but
> actual use, db inserts, file create, etc, ran >100% faster than with
> Hardware striping.
>
> I did the same test with Reiser and Ext2/3, none fared as well, but they
> all did better with LVM and striping than without.
>

What kernel release and XFS version are you using?
Anthony

> > > -----Original Message-----
> > > From: linux-lvm-admin@sistina.com
> >
> > [mailto:linux-lvm-admin@sistina.com]On
> >
> > > Behalf Of Anthony W. Marino
> > > Sent: Tuesday, 5 March 2002 10:39 a.m.
> > > To: linux-lvm@sistina.com
> > > Subject: [linux-lvm] LVM System
> > >
> > >
> > > Any thoughts or articles that would be usefull in determining the
> >
> > quality
> >
> > > on the following combination would be greatly appreciated:
> > >
> > > LVM 1.x
> > > 3Ware 7800 Raid Controller
> > > Maxtor 40GB harddrives
> > > XFS Journalling FS
> > > SuSE 2.4.18+ Linux
> > >
> > >
> > > Thank You,
> > > Anthony
> > >
> > > _______________________________________________
> > > linux-lvm mailing list
> > > linux-lvm@sistina.com
> > > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
> >
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm@sistina.com
> > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html