FreeBSD MySQL still WAY slower than Linux

[Andreas Braukmann]

--On Freitag, 17. Juni 2005 17:47 Uhr +0200 Matthias Buelow <mkb at incubus.de> wrote:

> Greg Barniskis <nalists at scls.lib.wi.us> writes:

> Is CentOS using ext2? I thought everyone moved to ext3 already, which
> provides nearly the speed of ext2+async but is safe due to its journal.
> If you make such comparisons, please use current technology, and not
> the status quo of 5 years ago.

ext3 delivers abysmal performance on concurrent write operations.
XFS is substantially faster. We experienced postgresql database
files becoming corrupt under high load (bulk imports; more than
a hand full updates per second) on xfs fileystems (2.6.3 - 2.6.5
timeframe).

We're about to move this client's (a pure Linux shop as yet)
postgresql servers to FreeBSD/amd64.
The first experimental setup on FreeBSD/amd64 (single processor,
1.4 GHz, 2 single SCSI disks 10kUPM, 5-stable, SMP-Kernel) delivers
the quintupled (application specific) insert/update throughput
over the current production setup (dual XEON, 4 spindle Hardware
RAID 1+0, Linux/i386 2.6.x SMP).

I hope to get my hands on a larger hardware testbed, so that I'd
be able to do side by side comparisons.


> [Apart from that, over the last decade, I've lost more UFS filesystems
> than ext2, so at least for me, that purported unsafety of ext2+async
> mounts is theoretical at best. In the end, with today's write-caches
> usually enabled, both are essentially the same, anyways.]

That makes your arguments pointless. I wouldn't even think of
running a database server on an async mounted filesystem; all the
more I wouldn't connect a drive with enabled write cache to a
production box.



-Andreas

I lost exactly two UFS filesystems since my very FreeBSD beginnings
and that was in the very early 3-current days shortly after the
very first softupdates patches ...