Discussion:
VMS Storage options
Add Reply
Mark Berryman
2020-10-23 19:07:55 UTC
Reply
Permalink
To those VSI folks who sometimes respond here:

Are you aware of any requests from your customers for iSCSI support?
I could provide SSD based storage to VMS systems if a reliable iSCSI
initiator were available.

I could also provide SSD based storage via Fibre Channel if VMS did not
require a UDID.

Here's a thought:
Since tape devices do not support UDID, their WWID is placed in
SYS$SYSTEM:SYS$DEVICES.DAT and their VMS device name is defined there.
Could the same be done for disks?

Mark Berryman
Robert A. Brooks
2020-10-25 16:02:55 UTC
Reply
Permalink
Post by Mark Berryman
Are you aware of any requests from your customers for iSCSI support?
In six years, I've heard of a single customer who asked about it.
Post by Mark Berryman
I could also provide SSD based storage via Fibre Channel if VMS did not require
a UDID.
We have several customers using non-HP arrays that are backed with SSD's for the
virtual disks. These arrays have been qualified by us for VSI VMS.
Post by Mark Berryman
Since tape devices do not support UDID, their WWID is placed in
SYS$SYSTEM:SYS$DEVICES.DAT and their VMS device name is defined there. Could the
same be done for disks?
I'll have to check on that.

My initial thought is yeah, we could probably make that work, but there are
enough differences between disks and tapes that we'd wind up with a lot of
device type-specific code that it would be a maintenance mess for marginal gain.

Add in the concern about breaking the fibre channel multipath stuff that's been
stable for 20+ years . . .
--
-- Rob
Mark Berryman
2020-11-13 15:42:48 UTC
Reply
Permalink
Post by Robert A. Brooks
Post by Mark Berryman
Are you aware of any requests from your customers for iSCSI support?
In six years, I've heard of a single customer who asked about it.
Post by Mark Berryman
I could also provide SSD based storage via Fibre Channel if VMS did
not require a UDID.
We have several customers using non-HP arrays that are backed with SSD's for the
virtual disks.  These arrays have been qualified by us for VSI VMS.
Post by Mark Berryman
Since tape devices do not support UDID, their WWID is placed in
SYS$SYSTEM:SYS$DEVICES.DAT and their VMS device name is defined there.
Could the same be done for disks?
I'll have to check on that.
My initial thought is yeah, we could probably make that work, but there
are enough differences between disks and tapes that we'd wind up with a
lot of
device type-specific code that it would be a maintenance mess for marginal gain.
Add in the concern about breaking the fibre channel multipath stuff
that's been stable for 20+ years . . .
(The following does not wrap at my end. Let me know if does when you
try to read it and I will try to reformat it).

So, I put together a quick test.

First, I created a new volume in my HP SAN but did not assign a UDID.
Next, I devised a patch to autogen where I replaced a status message
with code telling it to use the LUN if a UDID was not available.

Autogen then successfully created the device, or so I thought.

Here is the autogen output:

%IOGEN-I-FIBRE, port PGA0: Probing, FC-LA= 6, lun= 33-->time:13-NOV-2020
08:17:56.64
-IOGEN-I-FABRIC, Fabric address = 650000, port =
217000c0ff1291ed-->time:13-NOV-2020 08:17:56.64
-IOGEN-I-FIBRE, port PGA0: STD_INQ, V: HP , P: P2000G3 FC/iSCSI, R:
T252-->time:13-NOV-2020 08:17:56.64
-IOGEN-I-FIBRE, port PGA0: PARSE SCSI UDID, udid= 33, status=
1-->time:13-NOV-2020 08:17:56.64
etc.

%IOGEN-I-FIBRE, port PGB0: Probing, FC-LA= 5, lun= 33-->time:13-NOV-2020
08:17:58.94
-IOGEN-I-FABRIC, Fabric address = 650000, port =
217000c0ff1291ed-->time:13-NOV-2020 08:17:58.94
-IOGEN-I-FIBRE, port PGB0: STD_INQ, V: HP , P: P2000G3 FC/iSCSI, R:
T252-->time:13-NOV-2020 08:17:58.94
-IOGEN-I-FIBRE, port PGB0: PARSE SCSI UDID, udid= 33, status=
1-->time:13-NOV-2020 08:17:58.94
etc.

%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGA0
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGB0
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-CONFIGURED, configured device DGA33
%IOGEN-I-CONFIGURED, configured device DGA33

The device shows up with all appropriate paths:
$ show dev/full $1$dga33

Disk $1$DGA33: (ALDUR), device type HP P2000G3 FC/iSCSI, is online, file-
oriented device, shareable, available to cluster, device has
multiple I/O
paths, error logging is enabled.

Error count 0 Operations completed
0
Owner process "" Owner UIC
[SYSTEM]
Owner process ID 00000000 Dev Prot
S:RWPL,O:RWPL,G:R,W
Reference count 0 Default buffer size
512
Current preferred CPU Id 0 Fastpath
1
WWID 01000010:600C-0FF0-0013-0C44-6324-AD5F-0100-0000
Allocation class 1

I/O paths to device 8

Path PGA0.2170-00C0-FF12-91ED (ALDUR), primary
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: 13-NOV-2020 08:17:57.41

Path PGA0.2070-00C0-FF12-91ED (ALDUR)
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: Never

Path PGA0.2570-00C0-FF12-91ED (ALDUR)
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: Never

Path PGA0.2470-00C0-FF12-91ED (ALDUR), current
Error count 0 Operations completed
0
Last switched to time: 13-NOV-2020 08:17:57.41 Count
1
Last switched from time: Never

Path PGB0.2170-00C0-FF12-91ED (ALDUR)
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: Never

Path PGB0.2570-00C0-FF12-91ED (ALDUR)
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: Never

Path PGB0.2070-00C0-FF12-91ED (ALDUR)
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: Never

Path PGB0.2470-00C0-FF12-91ED (ALDUR)
Error count 0 Operations completed
0
Last switched to time: Never Count
0
Last switched from time: Never


However, any attempt to use the device comes back with a device offline
error. So far, I haven't been able find what is missing. If anyone has
any ideas, I would sure appreciate them.

Mark

Loading...