DL140 G3 performance

[AMRIT RANJAN]

Hi Neil,
thanks for your prompt reply
as you told that by passing the SAS controller has brought the performance up to where it should be, so which controller you are using right now, is it the embedded controller ?
The hdd ST3500320AS which you are using does it contain HP tag on it so we can consider the compatibility ? if it is then share the
spare part no.
if you are using sata hdd on sas controller then write cache is automatically disabled
so no chance for any enhancement in data writing process.
can you share off-line survey report for further analysis

........ Amrit

[Alun Webber]

I have also bought a number of the DL140 2GHz quad core servers (442993-425) and am disappointed with the RAID 1 performance using SATA drives under RHEL5. I am using the default driver installed with RHEL. T It is definitely running as a RAID 1 mirror - messages appear in syslog relating to rebuilding the mirror when I remove and re-insert discs.

When using hdparm -t to benchmark the discs, I have noticed that the read transfer rate is approximately equal to the claimed sustained transfer rate of a single disc and not twice the rate as expected and measured on other similar systems.

I have also noticed that during the RAID rebuilds the access LEDs are not on continuously as with other servers.

One of the other responses says that the drive write caches are disabled when using SATA drives with the LSI SAS 1068 controller. Is it that case that the write caches cannot be used with SAT drives or are they just disabled by default? If so how do I turn them on?

Any suggestions greatly appreciated.

[Pavol Čierny]

Hi,

I have the same problem with two HP DL145 G3 servers. 2x SATA drives in a Hot-plug SATA/SAS backplane with LSI controller.

Is it already fixed in a BIOS or should I connect the disks directly to the SATA connectors on the mainboard?

BTW do I need some special cabling or I'll just switch the cable from LSI controller to the SATA controller? (I don't have access to the servers right now, and they are already in production environment).


Thanks for any suggestions.

[Neil Stephens]

Don't know if this issue has been fixed in the BIOS, but we just connected the SATA drives directly to the motherboard using a couple of normal SATA cables.

[Pavol Čierny]

And what about the SAS backplane? Do I need to remove it? What about the power cabling? :)

I don't remember how does it look like inside the server so I have so many stupid questions :)

Thank you.

[Neil Stephens]

It was a while ago, but I'm pretty sure we left the SAS controllers in place and just unplugged the cables from the backplane the drives are plugged into. It's the backplane that provides the power for the drives.

If it's the same as in our servers, all you'll need are a SATA cable for each drive.

[Pavol Čierny]

Thanks for the answers :)...

Just last one stupid question... How long were the cables you used ... I think that I need cables that are at least 1 meter long...

Thanks.

[Neil Stephens]

Don't think they were that long - you certainly wouldn't need more than 1m.