[zfs-discuss] Flash to IT mode after build

Audun feitingen at gmail.com
Tue Apr 3 14:58:18 EDT 2018


I'm running my home pool with a LSI9211-8i in IR mode, and the OS has
pretty much direct access to the drives.

Disks show up the same size as in my previous system, smartmontools
works, and I can send commands to the SAS-backplane using this

I could flash it in IT mode, but it works fine for me the way it is
and I personally don't think there is a difference.

If the drives are the same size, and smartctl -A /dev/your-disk
returns meaningful info it is probably good enough.
Best Regards,

Audun Gangsto

On 3 April 2018 at 20:02, Andreas Dilger via zfs-discuss
<zfs-discuss at list.zfsonlinux.org> wrote:
> On Apr 3, 2018, at 7:30 AM, dag dg <dagofthedofg at gmail.com> wrote:
>> I have a ZFS storage pool already built, but it was done before I
>> fully understood some of the finer details of HBAs and related RAID
>> cards including the difference between IR mode firmware and IT mode
>> firmware. I have 2 x LSI 9311-8i HBAs that are up and running my
>> current ZFS pool that I believe came flashed with IR mode firmware.
>> The disks are all set to JBOD I believe and appear to be getting
>> passed through to the OS though I can't be sure.
>> My concern at this point is whether I should flash the firmware over
>> to IT mode or if that will cause more trouble that it's worth. In my
>> performance tests so far my current state seems solid and stable but
>> the fact that in my research I missed this kind of detail has me a bit
>> uncertain of the long term outcome.
>> Any insight would be appreciated.
> There is some potential that changing the adapter firmware may cause the
> devices to be labeled differently and skip a few sectors at the start when
> presented to the OS (e.g. removing a RAID device label from the disk).
> One way to check this non-destructively is to read the first few blocks
> from the disk under your current configuration, then remove a disk and
> install it in some non-RAID system and compare them, like:
>     dd if=/dev/sdb bs=1M count=16 | sha1sum
>     16777216 bytes transferred in 2.116622 secs (7926411 bytes/sec)
>     bbed83e350470cc17e54b38e78f4b06687597184  -
> You could also use md5sum or cksum if sha1sum is not installed.  If the
> checksums are the same, then the "raw" device presentation is the same
> as the "passthrough" device and it should "just work" after flashing the
> firmware.
> Cheers, Andreas
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