I would like to rely on a RAID-on-chip solution to control 24 SAS hard drives in a direct-attached environment. How would you approach this to get best bandwidth given that I'd like to spend less than $10,000 on the interconnect.
I've read that LSI 2208 chip can easily handle 8-drive SSD RAID6 in hardware. I'd like to harness its power to control 24 SAS hard drives over an expander in an external enclosure.
Currently I use an Infortrend S24S-G2240 external enclosure. It provides its own controller and expander. I'd like to use LSI 2208 controller for RAID6 somehow instead of the mystery controller in the enclosure.
P.S. I tried to create SAS-expander as a tag, but my rep on this site is low.
Best Answer
We're missing the obvious information... What type of external enclosure do you have, and what are its available connections?
Typically, external SAS controllers use 4-lane SAS SFF-8088 connectors to interface with the host-based adapter in the server.
Given that, the enclosure should have a SAS expander embedded on its backplane. That's how you'd be able to address the number of disks inside of the enclosure. Pretty standard.
I use HP D2700 enclosures, for instance. They have 25 x 2.5" disk bays and feature two chassis controllers that each take an SFF-8088 connection to the host system. I control them with either 1-port or 2-port LSI controllers. The expander is built into the external drive enclosure.
--Edit
Looking at the rear of the device you have, try connecting one port from your LSI HBA to P1 of the enclosure. Start there. I don't know if this device has multipath/MPIO capabilities, so you may need to contact support for that. But otherwise, this looks like any standard external JBOD unit... although, reading the specifications, it may be a SAS-attached SAN unit. You're better off using its embedded controller and logic rather than going the LSI approach.