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" ordered tag forced" message/high load with sym53c8xx and Netserver LP1000r

Vitaly Karasik_1
Honored Contributor

" ordered tag forced" message/high load with sym53c8xx and Netserver LP1000r

I have some strange problem with LP1000r and sym53c8xx (RHEL 2.1 ES , 2.4.9-27smp kernel):

it works very slo-o-o-owly when I write something to harddisk, I see CPU load up to 9 and "sym43c1010-33-0-<0,0>: ordered tag forced".

Do you have any idea?

does make sense to increase queue depth and if yes, how I do this?

Thanks,
Vitaly
2 REPLIES
Paulo A G Fessel
Trusted Contributor

Re: " ordered tag forced" message/high load with sym53c8xx and Netserver LP1000r

Vitaly,

Do you have to use 2.4.9-27smp?

I've noticed that older kernels like these have sluggish SCSI performance. Seems that something happened when the VM subsystem was rewritten.

I recommend using any recent kernel when you have ANY problem regarding SCSI performance.

Otherwise, I've made a little research and there were 2 major trends on this:

* upgrade the kernel, as I've already said
* upgrade the driver. Check the driver your kernel is shipping. If it's not sym53x8xx_2, then upgrade it.

HTH
Paulo Fessel
L'employé propose, le boss dispose.
Vitaly Karasik_1
Honored Contributor

Re: " ordered tag forced" message/high load with sym53c8xx and Netserver LP1000r

Thank you, Paulo.

In fact, I already solved this problem - it was broken disk or at leats disk with wrong firmware.

Regarding kernel/driver versions - of course, I use the latest on; just RH stays with 2.4.9 [with backported patches, of course] for RHEL 2.1.

Vitaly