iSCSI initiator and Dell PowerVault MD3000i

[Ivan Voras]

2009/12/17 Miroslav Lachman <000.fbsd at quip.cz>:
> please Cc: me, I am not subscribed to freebsd-scsi
>
> Sossi Andrej wrote:
>>> On 16. 12. 2009 15:57, Miroslav Lachman wrote:
>>> [...]
>>> I use MD300i with FreeBSD 7.0 and 7.1 with iscsi-2.2.2. It work fine.
>>> But be careful to configure MD3000i. MD3000i assign by default first
>>> disk to preferred controller 0, second disk to preferred controller 1,
>>> third disk to preferred controller 0, and so on. First, third, fifth...
>>> disks is usable from FreeBSD, but second, fourth,... disks result
>>> unusable.
>>> Work around: manually assign all disks to controller 0.
>>
>> When you say "unusable" do you mean you can't access it at all / it
>> errors even if it's the only path (drive) used? It would be normal if
>> you have for example two paths to each drive and can't mount the other
>> path if one path to the drive is mounted - this is not a usable
>> combination. You can use geom_multipath to get multipath failover.
>
> I got errors even in unmounted state.
> I tried iscsi-2.2.3 and got same errors. I tried second path first (device
> da0) and it produces same errors, then I run iscontrol for the first path
> (device da1) and everything is fine.
>
>  ---- path throught second controller: ERROR ----
> # diskinfo -t /dev/da0
> /dev/da0
>        512             # sectorsize
>        2998998663168   # mediasize in bytes (2.7T)
>        5857419264      # mediasize in sectors
>        364607          # Cylinders according to firmware.
>        255             # Heads according to firmware.
>        63              # Sectors according to firmware.
>
> Seek times:
>        Full stroke:    diskinfo: read error or disk too small for test.:
> Invalid argument
>
>
>  ---- path throught first controller: OK ----
> # diskinfo -t /dev/da1
> /dev/da1
>        512             # sectorsize
>        2998998663168   # mediasize in bytes (2.7T)
>        5857419264      # mediasize in sectors
>        364607          # Cylinders according to firmware.
>        255             # Heads according to firmware.
>        63              # Sectors according to firmware.
>
> Seek times:
>        Full stroke:      250 iter in   2.483517 sec =    9.934 msec
>        Half stroke:      250 iter in   2.575778 sec =   10.303 msec
>        Quarter stroke:   500 iter in   2.926170 sec =    5.852 msec
>        Short forward:    400 iter in   0.916901 sec =    2.292 msec
>        Short backward:   400 iter in   2.181790 sec =    5.454 msec
>        Seq outer:       2048 iter in   0.520920 sec =    0.254 msec
>        Seq inner:       2048 iter in   0.545300 sec =    0.266 msec
> Transfer rates:
>        outside:       102400 kbytes in   1.414997 sec =    72368 kbytes/sec
>        middle:        102400 kbytes in   1.454444 sec =    70405 kbytes/sec
>        inside:        102400 kbytes in   1.422527 sec =    71985 kbytes/sec

This is strange and probably indicates a bug somewhere. Can you check
your SAN configuration for example, wrong access permissions assigned
to the problematic port?

> Do you have experiences with iSCSI multipath? I read about geom_fox and
> gmultipath...

You should probably skip geom_fox and just use gmultipath. It works as
advertised, nothing fancy to report.