Unbelievably bad RAID-1 performance

Philip M. Gollucci philip at riderway.com
Sun Aug 5 18:42:51 PDT 2007


while writing to the disk

gstat screenshot
	http://people.apache.org/~pgollucci/disks.png

If I move the location to '/' (da0s1a) which AFAIK is at the center of
disk(smaller thus faster rpms) should be faster, performance is at least
100times worse which is the opposite I would expect.

Is there anything I can do to help this out.  I'm likely going to chuck
the raid card in the trash and just use one disk and reply on backups
which I already have going.

Dell PowerEdge 1435SC
	Dual Intel Core2 Duo 2.4GHz 4GB RAM
	RAID-1 Config with 2 disks at 240GB each
	FreeBSD 6.2-release-p5 amd64 custom kernel.

mpt0: <LSILogic SAS/SATA Adapter> port 0xdc00-0xdcff mem
0xeffec000-0xeffeffff,0xefff0000-0xefffffff irq 35 at device 8.0 on pci7
mpt0: [GIANT-LOCKED]
mpt0: MPI Version=1.5.12.0
mpt0: mpt_cam_event: 0x16
mpt0: Unhandled Event Notify Frame. Event 0x16 (ACK not required).
mpt0: mpt_cam_event: 0x12
mpt0: Unhandled Event Notify Frame. Event 0x12 (ACK not required).
mpt0: mpt_cam_event: 0x12
mpt0: Unhandled Event Notify Frame. Event 0x12 (ACK not required).
mpt0: mpt_cam_event: 0x16
mpt0: Unhandled Event Notify Frame. Event 0x16 (ACK not required).
mpt0: mpt_cam_event: 0xb
mpt0: Unhandled Event Notify Frame. Event 0xb (ACK not required).

da0 at mpt0 bus 0 target 0 lun 0
da0: <Dell VIRTUAL DISK 1028> Fixed Direct Access SCSI-5 device
da0: 300.000MB/s transfers, Tagged Queueing Enabled
da0: 237464MB (486326272 512 byte sectors: 255H 63S/T 30272C)







------------------------------------------------------------------------
Philip M. Gollucci (philip at riderway.com) 323.219.4708
Senior System Admin - Riderway, Inc. http://riderway.com
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Work like you don't need the money,
love like you'll never get hurt,
and dance like nobody's watching.


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