Ordered a couple of 1.2TB Enterprise Performance disks (Dell p/n 0RMCP3) to replace the nearline SAS constellation disks in an R320.
However, I have a performance issue with these new disks.
The Constellation ES.3 nearline SAS disks (ST1000NM0023) performed as expected. Sequential write using dd averages around 170 to 180MB/s in a JBOD configuration.
The new disks (ST1200MM0007) only do 20MB/s. No more. I've also tried to create a RAID on the H310 using 4 of these disks (RAID 5 3+1). Performance on the logical volume is about 60MB/s. So it seems the write speed on these disks is limited to 20MB/s. Any thoughts?
The H310 controller generally offers very low write performance for RAID 5 configuration because it does not have any data cache. Ensure that you BIOS, iDRAC and controller firmware is up to date.
The fact that the H310 performance is due to the hardware limitation in the controller itself, I would recommend that you upgrade to high level controller like the H710. You will benefit in terms of performance.
Again, we use the controller in JBOD. I've created the raid just as a test.
The controller performs just fine on Constellation ES.3 disks (Enterprise Capacity), matching the specified maximum sustained write rate of the disks at around 175Mbps.
However, using the much more expensive Enterprise Performance disks (Dell branded, listed as compatible and configurable together with the Perc H310) we only manage about 10% of that speed, JBOD or RAID. It seems to be an issue with the controller in combination with these disks.
The same disks perform just fine on a regular LSI HBA.
The USB flash drive on my keychain does sustained writes faster than this. It's not a minor performance issue, it's simply unusable. 20MB/s == 200Mbps. On a 6GBps bus!. The advice to buy a more expensive controller (which does NOT support JBOD by the way - which we need as we run ZFS!) is just ridiculous. It's like telling a customer that bought a Toyota and complains to the dealership that it won't drive any faster than 20 miles per hour to buy a Ferrari instead of fixing the car.