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I'm looking at adding some disks to one of my systems, for which I need to add an offboard HBA. Looking around, I came across the LSI MegaRAID SAS 9211-8i (LSI part number LSI00194) which looks quite interesting. LSI also seem to be popular in general, including right here.

Since I run ZFS, I plan on using the HBA itself as just a dumb controller, letting ZFS handle everything related to storage-level redundancy and recovery. The host OS is Linux (Debian/Linux to be precise).

While I doubt LSI will stop producing these cards any time soon, it would still be nice to know: does the 9211-8i add any data structures of its own to the disks when used in JBOD mode? In other words, can I unplug a disk from the 9211-8i, plug it into an alternate HBA, and everything "just keeps working"? Or will the OS then see some form of garbage on the disk that is not exposed through the LSI, which might interfere with ZFS' usage of the volume?

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No. The disks are raw and portable when used with a pure SAS HBA like the LSI-9211. There's no RAID metadata involved here.

Also see: ZFS SAS/SATA controller recommendations

  • Sounds promising, thank you. I see the accepted answer to the linked question says no MegaRAID cards, but interestingly enough lists the 9211-8i as a good card. Looks like that's about the firmware (the much-discussed IT versus IR mode/firmware) so I'd just need to make sure to flash the proper firmware onto the card before doing anything else. My local dealer states that the "MegaRAID" card has the same LSI part number as what both Amazon and Newegg lists (without MegaRAID). – a CVn Mar 13 '15 at 13:25
  • I use them without flashing the IT firmware, but they've been fine either way. – ewwhite Mar 13 '15 at 13:27
  • I'm not so much worried about the label, I just want it to work and not paint myself into a corner later on. :-) – a CVn Mar 13 '15 at 13:29
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If you flash these SAS HBA to IT mode they behave like normal SATA controllers. You can switch any time.

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