Does anybody have experience with a MD1420, mpr(4)

[Kenneth D. Merry]

On Wed, Nov 15, 2017 at 12:24:47 -0800, Lee Brown wrote:
> Hi,
> 
> This is my for foray into DAS, so please be gentle :)  Apologies if the
> cross-post is inappropriate, let me know.
> 
> I'm looking to build a SAS array with a Dell MD1420.  It will be attached
> via a SAS 9300-414E HBA in a Dell R330.
> 
> I've verified that the server / SAS card should be fine, but just wanted to
> know if anybody has set this up before, or if there's any obvious reason
> why it wouldn't work.  Dell can be a bit weird sometimes.
> 
> Any information is most welcome.

In theory it should be fine.  I haven't used a Dell enclosure recently, but
from posts here, it seems that they like to turn on Type 2 Protection
Information on the drives.  (Assuming you buy the drives from Dell.)

If they do that, you can either reformat, or see the patch here for the
mpr(4) driver to disable using protection information:

https://docs.freebsd.org/cgi/getmsg.cgi?fetch=308820+0+archive/2017/freebsd-scsi/20171022.freebsd-scsi

I haven't gotten around to changing things so that we detect the PI in the
da(4) driver and use 32 byte CDBs when type 2 protection is enabled.  (So
if someone else has time and wants to do it, feel free.  It will be
somewhat messy because we only allocate enough space for 16 byte CDBs inside
the CCB, so you'll need to allocate the CDB separately...)

If you use ZFS, you'll have checksum protection on your data anyway, so PI
would just be additional protection.

I would also suggest that you update to the latest firmware (currently
Phase 15) for the SAS controller.  You can do that with LSI's sas3flash or
the FreeBSD mprutil(8) utility.

Ken
-- 
Kenneth Merry
ken at FreeBSD.ORG