[Info-vax] HZS70 Unit number question
John Santos
john.santos at post.harvard.edu
Fri Apr 24 16:41:07 EDT 2009
In article <b_-dnRLWAaZuamzUnZ2dnUVZ_hydnZ2d at giganews.com>, rgilbert88
@comcast.net says...>
> Jeffrey H. Coffield wrote:
> > I have two Alphas (not clustered) connected to a HSZ70 that currently
> > has units D0 through D5 showing as DKC0 through DKC5. DKC0 through DCK4
> > are mounted on one system and DKC5 is mounted on the other.
> >
> > I have added some disks and want to add some new units but am concerned
> > about the SCSI disk numbering and the unit numbering. AFAIK the SCSI
> > controller takes a unit number (usually 7) so you could only have DKA0
> > through DKA6 on a bus.
>
> How many devices you can have on a bus depends on whether you are using
> narrow or wide SCSI. Narrow SCSI supports a three bit device address:
> zero through seven. Seven is usually used by the controller.
>
> Wide SCSI gives you zero through fifteen IIRC. ISTR that the convention
> remains that device 7 is the SCSI controller so your disks would be 0-6
> and 8-15 or something like that.
>
> >
> > I have read the CLI reference manual on the HSZ70 and can't see any
> > mention of there being a conflict between the unit number and the SCSI
> > addressing. It does say that a controller can present up to 8 units on
> > each target ID number. Both controllers show a SCSI target(s) of (0).
> >
>
> Never could afford an HSZ70. . . . HSZ40 and HSZ50, yes.
>
> > I only want to add two more units which would be DKC6 and DKC7 although
> > what the actual disk unit is is not important.
> >
> >
> > Jeff Coffield
> >
> >
HSZ's use a port/target/lun numbering scheme. When you set up the
units, you need to provide a port (matching one of the SCSI targets
listed under "show this_controller", a target (unique on that port)
and a LUN (always 0 in my experience, but I don't know if this is
required.) This generates a unit name "d<port>0<target>" I think
if you use port 0, you end up wth units named "d<target>" (leading
zeros suppressed), which is what you seem to have.
We usually number ours to match the disk names, which are derived from
the SCSI bus (the HSZ70 has 6, numbered one to six), and the disk unit
number, generated by the slot it is installed in -- 0 to 5, skipping
6 & 7 for the controllers, and 8 to 15, depending on how many expansion
shelves you have. (Maybe only HSZ80s have wide buses and allow 4
shelves/16 devices on each bus, but HSZ70's definitely allow for 2
shelves, 8 disks aince we have had some configured that way.)
The disk names come out DISK10000 for bus 1, disk 0, which we set
to PTL 1 0 0, and unit name d100, DISK10100 for bus 1, disk 1, which
ends up with PTL 1 1 0, and unit name d101 and so forth. VMS sees
these as DKC100:, DKC101:, etc. (Strongly advise using port allocation
classes to change the VMS names to $<alloc>$DKA100:, etc.)
For disks about 7, we shove the T's down by 2 (since there can't be
any disks at 6 or 7 because the SCSI controllers in the HSZ use those
unit numbers) so the disks have single-digit numbers. Don't have an
example at hand for units above 10.
The following is from an HSZ80, but I think HSZ70's work exactly
the same way:
HSZ> show disks
Name Type Port Targ Lun Used by
------------------------------------------------------------------------
------
DISK10000 disk 1 0 0 D100
DISK10100 disk 1 1 0 D101
DISK10200 disk 1 2 0 D102
DISK10300 disk 1 3 0 D103
DISK10800 disk 1 8 0 D104
DISK20000 disk 2 0 0 D200
DISK20100 disk 2 1 0 D201
DISK20200 disk 2 2 0 D202
DISK20900 disk 2 9 0 D205
DISK30000 disk 3 0 0 D300
DISK30100 disk 3 1 0 D301
DISK30200 disk 3 2 0 D302
DISK31000 disk 3 10 0 D306
DISK40000 disk 4 0 0 D400
DISK40100 disk 4 1 0 D401
DISK40200 disk 4 2 0 D402
DISK50000 disk 5 0 0 D500
DISK50100 disk 5 1 0 D501
DISK50200 disk 5 2 0 D502
DISK60000 disk 6 0 0 D600
DISK60100 disk 6 1 0 D601
DISK60200 disk 6 2 0 D602
DISK60300 disk 6 3 0 D603
HSZ> show units
LUN Uses
--------------------------------------------------------------
D100 DISK10000
D101 DISK10100
D102 DISK10200
D103 DISK10300
D104 DISK10800
D200 DISK20000
D201 DISK20100
D202 DISK20200
D205 DISK20900
D300 DISK30000
D301 DISK30100
D302 DISK30200
D306 DISK31000
D400 DISK40000
D401 DISK40100
D402 DISK40200
D500 DISK50000
D501 DISK50100
D502 DISK50200
D600 DISK60000
D601 DISK60100
D602 DISK60200
D603 DISK60300
HSZ>
If you are using RAID, you'll need a different numbering scheme
for your units; the point is you aren't stuck with single-digit
unit numbers on the HSZ.
By default the HSZ assigns the first free available unit number
to the CCL (a fake disk unit you can use to connect to the
HSZ with $ set host/scsi so you don't interfer with a real
disk unit, and so you can create and delete units without
deleting the unit you are using for a path (i.e. burning your
bridges while your in the middle of them!) You may have to
renumber your CCL and disconnect/reconnect (possibly doing
a "$ mcr sysman io autoconfig" in the middle so VMS will see
the new CCL device) so you can re-use the existing CCL unit
number under whatever numbering scheme you come up with.
HTH!
--
John
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