The Controllers: 1 x LSI MegaRAID 9280-24i4e And 2 x LSI MegaRAID 9260-8i
We used the trusty controllers from our previous test: two PCI Express-based LSI MegaRAID 9260-8i cards, each driving eight SSDs. A new addition was a second type of controller, LSI's MegaRAID 9280-24i4e, which can access all of the drives at once. Let's look at some facts about the 9260-8i first.
The LSI MegaRAID 9260-8i is based on the LSI SAS2108 RoC (RAID-on-chip), which employs a x8 PCI Express 2.0 interface that theoretically allows data rates of up to 4000 MB/s upstream and downstream. The "8i" in the name represents eight internal SATA/SAS ports, each of which provides a peak bandwidth of 6 Gb/s. The controller also has a 512 MB DDR2-800 memory cache, and, depending on the model, a battery backup unit (BBU) that ensures cached data can be written to the NAND flash after a power failure.
The second RAID controller, LSI's Mega RAID 9280-24i4e, offers 24 (instead of eight) internal SATA/SAS connectors, along with four external ones. Aside from the higher port count and larger PCB, the controller is very similar to its smaller colleague, the 9260-8i, because the PCI Express 2.0 interface (x8), RoC, and cache features are identical. Because the 9280-24i4e uses an expander on the controller to make more SATA/SAS ports available, the same bandwidth applies, too.
We used three different test setups to determine the typical performance of the 16 SSDs:
- Eight SSDs on the LSI MegaRAID 9280-24i4e
- 16 SSDs on the LSI MegaRAID 9280-24i4e
- 16 SSDs on 2 x LSI MegaRAID 9260-8i
For all three configurations we created a software RAID in Windows 7. In every case, the configuration of the SSDs went through the controller software from LSI, called MegaRAID Storage Manager.
Creation of a RAID 0 Stripe on the LSI 9280-24i4e
The SSDs can be aligned into arrays using the MegaRAID Storage Manager by following the following steps (LSI MegaRAID 9280-24i4e with 16 SSDs):
The MegaRAID Storage Manager lists all the controllers connected to SSDs.
Using the context menu command “Create Virtual Drive,” you can create a Virtual Drive designated as a RAID array.
Under RAID Configuration, you can choose between the options “Simple” and “Advanced."
We used the SSDs to form a RAID 0 for the test.
Once all the drives are added to the RAID, further parameters can be defined.
The MegaRAID Storage Manager shows a summary of all the parameters, and creates the RAID array with a click on “Finish."
The Virtual Drive, comprised of 16 SSDs, is now created and has a size of 3.7 TB. Further configuration occurs in Windows’s disk management.
