LSI 9260-8i RAID Configuration – RAID 5, 6, 10, or Bad Idea?

hardware-raidlsissd

We're provisioning a new production server for our reasonably busy website. Our choice of host have available a 6 drive configuration with a LSI 9260-8i card.

My initial thought was to fill all six bays with SSDs (Intel 520 256gb) and set them up in RAID. Good, bad, or terrible idea?

Can the card handle it? Should we be using RAID 5, 6 or 10? This would be the first time the provider have filled all six slots for this rackmount with SSDs, so they're a bit hesitant. I'm wondering if somebody else with this card has done something similar in a production environment.

We do about 43gb of writes per day and currently use about 300gb of storage. The server acts as webserver, database, and image store for approx 1 million files. The plan is to underprovision the SSDs by approximately 10% to 20% to increase their overall lifespan & performance.

The fallback option is 2x480gb SSDs in RAID 1 and another 2x1TB HDDs in RAID 1.

The motivation behind this is that the server rental cost difference between 2xSSDs and 6xSSDs is minimal (compared to the overall cost of the rental). We do not have any special high-IOPs requirements. However, if the configuration is known to work, I don't see a good reason to not use it and not have to worry about having separate 'fast and small' and 'slow and large' disks.

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Edit 10/09/2012: Andy (who commented below) has suggested over IRC that JBOD with RAID 1 might be a good idea. I'm favouring this as:

  • It's a less "complicated" solution
  • I don't need the extra IOPS & throughput that RAID 0 or RAID 5 would provide
  • but I do need the extra space that they'd provide
  • it would ensure that the disks are worn unevenly, reducing the risk of a concurrent failure (although the risk of both slaves in a RAID 1 failing is still there)

Best Answer

No, it's not a bad idea. How will you perform the under-provisioning overprovisioning?

The LSI 9260 card is SSD compatible and there aren't any IOPS/throughput issues for you to worry about. It's a 6Gbps controller, as are the Intel 520 SSD's. If anything, I'd make sure your system has a 1:1 port allocation and avoid any SAS expanders. That's the only issue to consider.

I don't use the LSI RAID cards, but I do use the LSI SAS HBA cards (9211, 9205) with SSD's and ZFS storage solutions. I've never had any problems with compatibility, detection, temperature, monitoring, etc.

Edit:

@MichaelPearson I ask because some people do this by modifying drive firmware. I don't have much detail on that. Partitioning seems to be the way to go. Also, the term here would be overprovisioning the SSD (for Google result purposes). @chopper3, the benefit is in performance with multiple drives. The SSD equivalent of short-stroking, sorta.

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