Ultra320 drives run at Ultra2 speed in disk enclosure

[Fabian Tuender]

Hi,

We have a DL380 server with a 642 SCSI controller connected to a 4314R Disk Enclosure with 7 72GB Ultra320 scsi disks in raid 5. When I look in the ACU or PMP I see that it claims that the disks are all running on ULTRA2 SCSI speed. What could be wrong ?

With kind regards,
Fabian

[JohnWRuffo]

Fabian:
Make sure you have bios version 2.26B installed on the 642 controller.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=PSD_EX030903_CW02

You should also have the latest SA642 drivers installed for your O/S.

[Fernando Bandeira]

Hi Fabian,

Usually degraded performance on a SCSI bus is the result of one of two things :

1 - You are mixing faster and slow devices on the same bus (for example Ultra320 drives with Ultra2 devices). If you mix different speed devices on the same bus, they will operate as fast as the lowest common denominator.
2 - You are placing faster devices on a slow bus. Even if you have fast devices, but place them on a slow bus, they will only opertae at the slowest speed (ie the bus speed).

In your case I see you are attaching to a 4314 drive enclosure. The 3 in the naming convention says that this shelf is capable of ULTRA3 speeds maximum, which means that you will get a theoretical half of the performance than had it been a 4414/MSA30 SB.

So have a look to see if you are making use of any other slower devices on the same SCSI channel. Also, please note that you might not see a performance gain by moving from ULTRA 2 to ULTRA 3, and from ULTRA 3 to ULTRA 320. If you are not fully saturating the ULTRA2 bus, then moving to a faster bus should hardly add any performance benefit.

Regards
Fernando