--v9Ux+11Zm5mwPlX6
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Thu, Mar 08, 2007 at 08:34:21PM +1100, Paul Ripke wrote:
> On Thu, Mar 01, 2007 at 08:19:49PM +0100, Edgar Fu? wrote:
> > I've no idea whether this problem is actually LFS related or
> > I was just hitting a coincidence.
> >=20
> > We have performance problems on our mySQL server. As analysis
> > showed that disk I/O, in particular seeks, were the problem,
> > I thought it might be worth to try LFS. So we dumped the
> > database, set up an LFS partition on a development server and
> > fed the dump into mysql. First, everything went as expected
> > (mysqld being CPU bound). Then, as most of the database seems
> > to have been written, we observed ioflush consuming 100% CPU
> > load. From then on, any attempt to access the LFS partition
> > (ls, du) locked up in vnlock state.
>=20
> IMHO: LFS really isn't suitable for databases - every random
> write operation can fragment the file on disk. Do a few
> thousand random writes and the database files will be very
> fragmented.
>=20
> While it'll still all work, I'm sure this can't be efficient.

Yes. FFS and LFS each have different "bad" workloads. For LFS, one is
overwriting blocks in files. That's exactly what a database does a lot.=20
:-(

Take care,

Bill

--v9Ux+11Zm5mwPlX6
Content-Type: application/pgp-signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (NetBSD)

iD8DBQFF8EWKWz+3JHUci9cRArFxAJ9lCS6us7ur9dVV0RNX+A+hbSHPowCfRYrQ
ulsirIQGj2TLHJuj3uCqNHA=
=JeWB
-----END PGP SIGNATURE-----

--v9Ux+11Zm5mwPlX6--