LSI MegaRAID SAS 9260-8i: Up Close and Personal
LSI’s new-generation controllers can be easily distinguished by the number 92 in the beginning of the model name. They split into three series: HBA, Value and Feature. The HBA series is comprised of controllers without a XOR coprocessor and supporting but the basic array types RAID0, RAID1, RAID1E and RAID10. They still need a rather advanced processor (a PowerPC 440 clocked at 533MHz), though. For the two senior series LSI has developed a new processor LSISAS 2108 with a clock rate of 800MHz. As a matter of fact, the Value and Feature series are very similar, differing with the type of connectors only. The Feature series models are equipped with external SFF-8088 connectors while the Value series, like the 9260-8i model we’ve got, has only internal SFF-8087 ports. So, everything we’ll write below refers to all products from the two new series.
The controller does not differ externally from LSI’s previous series. It is a low-profile MD2 card whose main chip is covered by a needle-shaped heatsink. Like all its cousins (including the 4-port models), the LSI 9260-8i carries 512 megabytes of DDR2 SDRAM clocked at 800MHz. It is kind of unserious to install less memory on board whereas a larger amount is not really necessary (at least on configurations similar to our testbed). An important, although not conspicuous, difference from the previous series is that the interface for the mainboard has changed. Yes, the controller now uses PCI Express version 2.0 which means that it can pump up to 64GBps through its eight PCI Express lanes, which is more than enough even for eight fully loaded SAS 6Gbps ports.
Everything is conventional when it comes to the array types supported. New types have not been invented while nearly every full-featured controller today supports all the old types like RAID0, 1, 5, 6 and combinations thereof.
LSI’s new controllers support a battery backup unit. Each of them is compatible with the iBBU07 model which had been previously used for the LSI 8880EM2 only.
SSD support must be noted, too, although it is not unique to this controller series. It has been added with the latest version of LSI’s software which was released almost together with the new controllers. You should not expect any miracles from that, but RAID controllers have learned to identify SSDs as a separate class of storage devices that are completely different from HDDs. There is no sense in such operations as patrol reading of the surface, for example. Hopefully, cache data are written to an SSD less often, which should affect its service life positively.