IBM x335 onboard LSI 1020 (mpt) poor performance

Thu Apr 15 12:51:12 PDT 2004

Hello.

We have a bunch of IBM x335's with an on-board LSI Logic 1020, which I think
is a single-channel version of the 1030.

The x335 has a hotswap SCSI backplane, with room for two hotswap disks. If
we use these independently, performance is fine.

However, as soon as we use the two disks in a RAID-1 configuration (made
from the LSI BIOS), I/O-performance goes way down - writes are averaging
around 1.9-2.5 MB/sec, and reads are anywhere between 5-15 MB/sec.

My primitive test is dd'ing 100 MB data from /dev/zero to a file, and that
averages around 45 seconds. The same test performed on the same server,
using a stock RedHat Linux 8, averages around 2 seconds. I've tested on
8 more-or-less identical x335's running FreeBSD 4.9 and once with 5.2.1,
and all give the same, poor performance.

Google only finds two things related to this - Matthew Jacob mentioned he
got limited read performance[1] but I'm not sure this is related, and Eimar
Koort seemed to experience[2] the same problems as us, but got no answer.

dmesg details:

mpt0: <LSILogic 1030 Ultra4 Adapter> port 0x2300-0x23ff mem 0xfbfe0000-
 0xfbfeffff,0xfbff0000-0xfbffffff irq 9 at device 1.0 on pci1
pass1 at mpt0 bus 0 target 8 lun 0
pass1: <IBM 25P3495a S320  1 1> Fixed Processor SCSI-2 device
pass1: 3.300MB/s transfers
da0 at mpt0 bus 0 target 0 lun 0
da0: <LSILOGIC 1030 IM 1000> Fixed Direct Access SCSI-2 device
da0: 160.000MB/s transfers (80.000MHz, offset 63, 16bit), Tagged Queueing Enabled
da0: 70001MB (143364061 512 byte sectors: 255H 63S/T 8924C)

The chip on the mainboard says "LSILogic 1020 B0". Firmware/BIOS for both
mainboard, drives and SCSI-controller are the newest available on IBM's
support-site, but as mentioned, RedHat performs fine and I'd guess Windows
would too, so it seems it's an issue related to FreeBSD only, and then,
only when using RAID.

I'll gladly test experimental stuff to find the cause of this. We have a
lot of these in production, but I can scrounge up 1-3 boxes for testing
different configurations/drivers/OS'es if anybody would like to help us.
Any help would be much appreciated.

-- 
Best Regards
Kenneth Schmidt

[1] http://www.mail-archive.com/freebsd-hackers%40freebsd.org/msg36657.html
[2] http://news.gw.com/freebsd.scsi/3809