Bad Perf. w/ Dell Poweredge 2500 & 2600

[Aeridyne]

I have 2 servers here, a Dell Poweredge 2500 and 2600. Each of them has the following configurations for hardware

2500;
Dell Perc 3/di onboard Raid controller connected to the backplane
5 drives connected to the backplane
all are Quantum Atlas 10K III Ultra3(U160)

I created a new configuration for these, 2 drives in a RAID 0 & 3 drives in a raid 5

Performance is less than what i expected w/ sustained read/write at about 25 mb/s or less.

2600;
Dell Perc 4/di onboard Raid controller connected to the backplane
5 drives connected to the backplane
all drives are Maxtor Atlas 10k III Ultra 320

(all of the drives are 36 gb for both models of poweredge)

again this one i created a new configuration for these and set it up the same, 2 in raid 0 - 3 in raid 5

Performance is better on the raid 0, but still crappy at about 60 mb/s
The raid 5 was dismal, with only about 30 mb/s

Both are running on Server 2003, I have tried w/ Service pack 2, without service pack 2, base drivers, and Dell drivers for both.

I used HDtach for the benchs.

Help Please! I wanted to use these servers to test different software and configurations for my organization but the performance is just not there. Any help is much appreciated and TYIA.

 

[Aeridyne]

anyone? I need SCSI guidance from those who know it's ways

 

[Aeridyne]

I found this:

http://support.microsoft.com/kb/923076/

But it is a bit difficult to understand, i don't know how to check what my partition offset and sector size are.

 

[drebo]

How long did you let them sit before testing?

RAID 5 needs to establish parity and can be slow while initializing the disks. RAID 0, depending on the implementation, could have a similar initialization phase. Any hard disk access during these times will be slow.

 

[Aeridyne]

I have installed/updated the System bios to the latest, the ESM and backplane to the latest firmware, and the Raid card itself to the latest firmware, also I have the latest drivers loaded in windows for the perc 3/di controller.

 

[Aeridyne]

Originally posted by: drebo
How long did you let them sit before testing?

RAID 5 needs to establish parity and can be slow while initializing the disks. RAID 0, depending on the implementation, could have a similar initialization phase. Any hard disk access during these times will be slow.

These disk have been in use for some time, also, I know about initialization, scrub, etc times and i let the Raid card finish those before I even reboot when i created the containers, but thank you for the suggestion.

 

[Aeridyne]

I have tried a whole lot of tests at this point and still have not solved anything.

I have tried;
different block size and cluster size combinations on the controller and partition sizes
I have the latest drivers, firmware, etc for the whole system
Tried different configurations for Raid 0 and Raid 5

Nothing gives my anything more than a few mb in variance of speed and it remains low at about 20-25 mb/sec

Any help would be appreciated

 

[jterrell]

Dell raid performance was crappy for me.

What I found was they used some craptastic cards that were stripped down oem versions of otherwise quite nice cards.

The company I was at back then no longer uses dell pc's for that reason, the performance was simply unacceptable so they went with IBM boxes.

 

[NesuD]

Originally posted by: Aeridyne
I found this:

http://support.microsoft.com/kb/923076/

But it is a bit difficult to understand, i don't know how to check what my partition offset and sector size are.

Toss this one out. The controller on those Dell servers is a full hardware based controller and they compensate in hardware for the offset issue that degrades write performance. in any case the offset issue only really effects write performance and has little if any impact on read performance.

 

[Stan]

I had to toss PCIx SATA raid cards in my poweredge servers to get anything out of them. The Dell OEM raid card seemed to benchmark SLOWER when the drives were in RAID1 then when they were standalone!