Are there any special settings for LSI RAID controllers?


#1

Are there any special settings for LSI RAID controllers?

Yes. In general, Aerospike prefers to have direct attached hardware. However, if you are using specific RAID controllers, you may be able to get much better throughput with LSI RAID controllers by using MegaCli.

You can get the latest version at: http://www.lsi.com/support/Pages/Download-Results.aspx?keyword=MegaCli

The following command can be used to set up the drives as RAID0. This has been tested on a Dell 720xd, but should work for any server with a RAID controller that supports MegaCli.

MegaCli64 -CfgLdAdd -r0 [<enclosure number>:<drive slot>] -a<adapter number>

is likely 32 will vary depending on the SSD you wish to set up as RAID 0. this is the ID of the RAID adapter (likely 0)

The following will then put the SSDs in the appropriate mode (write-through and no read ahead)

MegaCli64 -LDSetProp WT -L<drive slot> -aALL; MegaCli64 -LDSetProp NORA -L<drive slot> -aALL

will vary depending on the SSD you wish to set up as RAID 0.

The main points are a RAID0 volume for each drive with Write Through (WT) and NO Read Ahead (NORA). With those settings on that card, you will get the LSI FastPath http://www.lsi.com/channel/products/storagesw/Pages/MegaRAIDFastPathSoftware.aspx


Does write cache on RAID controller matter for SSD?
#2

LSI has now published an article comparing performance of their MegaRAID software using the FastPath. These are for workloads that have some similarity to how Aerospike uses SSDs. Aerospike has noticed not only improved performance on single disks, but much better parallel performance when using multiple SSDs.

The LSI product brief can be found at:

http://www.lsi.com/downloads/Public/Advanced%20Software/LSI%20MegaRAID%20FastPath%20Software/LSI-PB-MR-FastPath.pdf