Recommended HBA for ZFS, contemporary

[Borja Marcos]

> On 22 Aug 2016, at 20:36, Dmitry Morozovsky <marck at rinet.ru> wrote:
> 
> On Mon, 22 Aug 2016, Mike wrote:
> 
>>>> LSI SAS 2008 Based HBA, there are dozens of OEM available for Budget Prices
>>> 
>>> With the IT firmware.
>> 
>> What's the significance of "IT firmware"?
> 
> ability to export raw disk device withou unnatural intelligence of a controller 
> to mangle with data :)

That’s a serious problem with other HBAs, which are designed as “RAID” cards. That means you need
some effort to have them give you direct, CAM access to the disks.

The LSI2008 with IR firmware, however, is a different beast. It’s an HBA with an add-on RAID thingy. Provided
you don’t create logical volumes on it, the mps(4) driver will just make it behave like a simple HBA, which is excellent.

Although some claim that there is a performance difference between IR and IT firmware on the same card, according to
the helpful LSI guys in freebsd-scsi the difference should be negligible. 

Anyway in case you want to cross flash from IR to IT it’s possible, although unsupported by LSI. However, sas2flash
checks wether the card is running IT or IR firmware and it will abort cross flashing attempts, except that at least
one old version does not abort and lets you proceed.

The procedure is described in a rather religious manner (religious because they don’t say that a particular
version is needed, nor why) here:

http://forums.overclockers.com.au/showthread.php?t=1045376

If I remember well I tried a LSI utility from the same date more or less, and it worked as well. More recent versions of sas2flash will
fail, however.

Cheers,




Borja.