Performance problems:Did PE2850 ship with SCSI-2 backplane?

Brent Kimberley Brent.Kimberley at durham.ca
Tue Sep 6 07:26:37 CDT 2011


Hi,

I have a question for the group.  Does anyone know if PE2850 servers were shipped with a SCSI-2 backplane?

This PE2850 was shipped from with the following options: 
    a)  N7108 (Module, Information, Backplane 1X6, P2850); AND, 
    b) T8677 (Assembly, Cable, Scsi, Backplane Riser, CHANNEL A...)

I believe the machine has been crippled by a SCSI-2 backplane.

If true, can anyone advise a simple way to work-around the issue?  Perhaps jumper settings, cables, etc.?

Has this happened to anyone else?

Observations:
- The system has been undergoing a slow/prolonged end-of-life failure for several years 
- The backplane reports SCSI-2 (i.e. 10MB/sec)
- performance does not and did-not meet expectations  
    * system yields 1 to 4 MB/sec for bulk sequential reads (i.e. dd bs=4MB if=/dev/<raw-SCSI-320-disk-array> of=/dev/null count=1000)
    * System should yield 40 to 240 MB/sec for bulk sequential reads
    * System performs worse during random access reads
- system has low throughput / high latency (system should have high throughput / low latency as it was professionally configured & contains only OEM, enterprise, Ultra SCSI 320 components)
- unable to backup or archive in a timely fashion
- system barely meets minimum "sunny-day" expectations when running contiguously for 8 to 18 hours per day.

Thanks,
Brent


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