[Beowulf] Re: [OT: LTO Ultrium (3) throughput?

Joe Landman landman at scalableinformatics.com
Wed Jun 18 21:09:30 EDT 2008


David Mathog wrote:
> Joe Landman wrote:

[...]

> Maybe it will mean more to you than it does to me...
> 
> % lsscsi --long
> [8:0:0:0]    tape    HP       Ultrium 3-SCSI   D21D  /dev/st0
>   state=running queue_depth=32 scsi_level=4 type=1 device_blocked=0
> timeout=900

Hmmm... queue_depth of 32?  On a tape?  Weird.  There has been some 
strangeness in the TCQ/NCQ layers.  Might want to try to set this to 1 
and see if it helps

echo 1 > /sys/block/st0/device/queue_depth

(note: some drivers don't support changing the queue_depth)

> lspci -v 
> 04:04.0 SCSI storage controller: Adaptec ASC-29320ALP U320 (rev 10)
> 	Subsystem: Adaptec ASC-29320LPE PCIe U320
> 	Flags: bus master, 66MHz, slow devsel, latency 32, IRQ 19
> 	I/O ports at 4400 [disabled] [size=256]
> 	Memory at d8400000 (64-bit, non-prefetchable) [size=8K]
> 	I/O ports at 4000 [disabled] [size=256]
> 	[virtual] Expansion ROM at d8600000 [disabled] [size=512K]
> 	Capabilities: [dc] Power Management version 2
> 	Capabilities: [a0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/1
> Enable-
> 	Capabilities: [94] PCI-X non-bridge device

Looks like a PCI-x adapter.  This shouldn't be an issue though.

Try changing the block size. 2M to 8M, and see what happens.

-- 
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
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