HAST + ZFS + NFS + CARP

[Jordan Hubbard]

> On Jul 1, 2016, at 11:23 AM, Ben RUBSON <ben.rubson at gmail.com> wrote:
> 
> Would you say that giving an iSCSI disk to ZFS hides some details of the raw disk to ZFS ?

Yes, of course.

> I though that iSCSI would have been a totally "transparent" layer, transferring all ZFS requests to the raw disk, giving back the answers, hiding anything.

Not really, no.  There are other ways of talking to a disk or SSD device, such as getting S.M.A.R.T. data to see when/if a drive is failing.  Drives also return checksum errors that may be masked by the iSCSI target.  Finally, there is SCSI-2 and there is SCSI-3 (where things like persistent reservations are implemented).  None of these things are necessarily implemented by iSCSI.

- Jordan