Support TrueNAS SCALE

[datamattsson]

Setting the hardware_handler to "1 alua" breaks for TrueNAS SCALE:

Oct 30 12:36:14 grisvakt-cpu3 kernel: sd 8:0:0:0: [sdb] Attached SCSI disk
Oct 30 12:36:15 grisvakt-cpu3 multipathd: sdb: add path (uevent)
Oct 30 12:36:15 grisvakt-cpu3 kernel: sd 7:0:0:0: alua: not supported
Oct 30 12:36:15 grisvakt-cpu3 kernel: sd 7:0:0:0: alua: not attached
Oct 30 12:36:15 grisvakt-cpu3 kernel: device-mapper: table: 252:0: multipath: error attaching hardware handler
Oct 30 12:36:15 grisvakt-cpu3 kernel: device-mapper: ioctl: error adding target to table
Oct 30 12:36:15 grisvakt-cpu3 multipathd: mpatha: failed in domap for addition of new path sdb
Oct 30 12:36:15 grisvakt-cpu3 multipathd: uevent trigger error

Removing the multipath.conf entry and it attaches fine.

Oct 30 12:41:08 grisvakt-cpu3 kernel: sd 22:0:0:0: [sdb] Attached SCSI disk
Oct 30 12:41:08 grisvakt-cpu3 multipathd: mpatha: load table [0 67108864 multipath 0 0 1 1 queue-length 0 1 1 8:0 1]
Oct 30 12:41:08 grisvakt-cpu3 multipathd: mpatha: event checker started
Oct 30 12:41:08 grisvakt-cpu3 multipathd: sda [8:0]: path added to devmap mpatha
Oct 30 12:41:08 grisvakt-cpu3 multipathd: sdb: add path (uevent)
Oct 30 12:41:08 grisvakt-cpu3 multipathd: mpatha: load table [0 67108864 multipath 0 0 1 1 queue-length 0 2 1 8:0 1 8:16 1]
Oct 30 12:41:08 grisvakt-cpu3 multipathd: sdb [8:16]: path added to devmap mpatha

Repeating the attach with hardware_handler "0", using TrueNAS CORE, ALUA seems to be detected anyhow:

Oct 30 13:12:30 grisvakt-cpu3 kernel: scsi 25:0:0:0: alua: supports implicit TPGS
Oct 30 13:12:30 grisvakt-cpu3 kernel: scsi 25:0:0:0: alua: device naa.6589cfc0000000e31e421641d7655045 port group 1 rel port 11
Oct 30 13:12:30 grisvakt-cpu3 kernel: scsi 25:0:0:0: alua: Attached
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: Attached scsi generic sg1 type 0
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: Power-on or device reset occurred
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: alua: rtpg retry
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [alua] Sense Key : Unit Attention [current]
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [alua] Add. Sense: Power on occurred
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [sda] 67108864 512-byte logical blocks: (34.3 GB/32.0 GiB)
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [sda] 8192-byte physical blocks
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [sda] Write Protect is off
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [sda] Optimal transfer size 1048576 bytes
Oct 30 13:12:30 grisvakt-cpu3 kernel: sd 25:0:0:0: [sda] Attached SCSI disk
Oct 30 13:12:30 grisvakt-cpu3 multipathd: sda: add path (uevent)
Oct 30 13:12:30 grisvakt-cpu3 multipathd: mpathc: load table [0 67108864 multipath 0 0 1 1 queue-length 0 1 1 8:0 1]
Oct 30 13:12:30 grisvakt-cpu3 multipathd: mpathc: event checker started
Oct 30 13:12:30 grisvakt-cpu3 multipathd: sda [8:0]: path added to devmap mpathc

Hence removing the hardware_handler set to "1 alua" explicitly would seem safe. Although, messages differs slightly when attached using "1 alua":

Oct 30 13:33:11 grisvakt-cpu3 multipathd: sdb: add path (uevent)
Oct 30 13:33:11 grisvakt-cpu3 kernel: sd 29:0:0:0: alua: port group 01 state A non-preferred supports TolUSNA
Oct 30 13:33:11 grisvakt-cpu3 kernel: sd 29:0:0:0: alua: port group 01 state A non-preferred supports TolUSNA
Oct 30 13:33:11 grisvakt-cpu3 multipathd: sdb [8:16]: delaying path addition until mpathe is fully initialized
Oct 30 13:33:11 grisvakt-cpu3 multipathd: mpathe: performing delayed actions
Oct 30 13:33:11 grisvakt-cpu3 multipathd: mpathe: load table [0 67108864 multipath 0 1 alua 1 1 queue-length 0 2 1 8:0 1 8:16 1]
Oct 30 13:33:11 grisvakt-cpu3 kernel: sd 29:0:0:0: alua: port group 01 state A non-preferred supports TolUSNA
Oct 30 13:33:11 grisvakt-cpu3 kernel: sd 29:0:0:0: alua: port group 01 state A non-preferred supports TolUSNA

TrueNAS SCALE docs says ALUA is only supported on the Enterprise product of TrueNAS SCALE.

The fundamental problem is that there's no way to distinguish CORE and SCALE (or "Enterprise") from a device perspective, which is not ideal.

Signed-off-by: Michael Mattsson michael.mattsson@gmail.com