AMCC, Areca & LSI Serial RAID Controllers

LSI Corporation MegaRAID SAS8888ELP

The third candidate in our RAID controller update is LSI Corporation’s MegaRAID SAS8888ELP. It is named after LSI Corporation’s own storage processor, which it calls LSISAS1078 "RAID on Chip". Different from the other products, it’s not based on an Intel IOP RISC unit, but on a 500 MHz PowerPC core. The result is excellent, as it enables the SAS8888ELP to perform on the same level as the 3Ware 9690SA.

LSI is very careful when it comes to potentially broken hard drives. When we removed a drive to simulate a drive failure, the controller software would recognize the drive as "unconfigured and bad" once we reconnected it. The result is that you cannot use the drive anymore because the software assumes that it might not be reliable. This is good to prevent the reinstallation of a faulty drive, but it’s annoying if you accidentally remove a wrong drive. You have to enter the controller BIOS and declare the drive "unconfigured and good" before you can reintegrate it with the array. The rebuild process then commences right away.

Although this is a low-profile card suitable for 2U rackmount servers, it carries two internal and two external multi-lane SAS connectors, each of which offers four SAS ports. However, you can only use two of them, but you can also select any two. LSI Corporation uses an x8 PCI Express interface, but it deploys faster cache memory than the others. The controller card has 256 MB or 512 MB DDR2-667 ECC RAM. There is an optional battery backup unit and support for all common RAID level including the nested RAID modes 10, 50 and 60. It almost goes without saying that the device offers support for Online Capacity Expansion and RAID Level Migration.