Operating System - OpenVMS
1748157 Members
3976 Online
108758 Solutions
New Discussion юеВ

Re: port allocation class

 
SOLVED
Go to solution
Gregg Parmentier
Frequent Advisor

port allocation class


I'm adding a new SAN to my cluster once I get it upgraded to 7.3-2, and I've been reading up on setting the port allocation class for the fiber channel controllers connecting to the shared device.

The documentation says to use CLUSTER_CONFIG.COM, CLUSTER_CONFIG_LAN.COM or, if nether of those can be used for some reason, to use SYSBOOT> SET /CLASS to make port allocation class changes. These methods make a change to SYS$SYSTEM:SYS$DEVICES.DAT.

Is there anything the recommended methods do that isn't done by just editing the file? I do see by experimentation that editing the file does change the port allocation class. I was wondering if there's anything editing the file doesn't do that should be done.
12 REPLIES 12
Jim_McKinney
Honored Contributor
Solution

Re: port allocation class

> I was wondering if there's anything editing the file doesn't do that should be done.

Not that I've noticed - I've frequently just edited SYS$DEVICES.DAT, got the expected result, and not experienced any problems.
Jim_McKinney
Honored Contributor

Re: port allocation class

> setting the port allocation class for the fiber channel controllers

Why?
Gregg Parmentier
Frequent Advisor

Re: port allocation class


>> I was wondering if there's anything editing the file doesn't do that should be done.

> Not that I've noticed - I've frequently just edited SYS$DEVICES.DAT, got the expected result, and not experienced any problems

Thanks. That's what I was expecting.

>> setting the port allocation class for the fiber channel controllers

> Why?

The node alloclass is set to different values on the two servers to allow for access to all internal disks from both systems for temporary storage space. I need to set the port alloclass so the controllers in both machines have the same alloclass for the shared device.

Or does a Sun/Hitachi 9985 identify itself to VMS in a way that makes that unnecessary?
Jim_McKinney
Honored Contributor

Re: port allocation class

> Sun/Hitachi 9985

You just left my universe... I'm only familiar with HP FC offerings which present an allocation class of 1 for disks and 2 for tapes.
Duncan Morris
Honored Contributor

Re: port allocation class

Gregg,

the fibre disks will appear as $1$DG, and fibre tapes as $2$MG, regardless of your SYSGEN ALLOCLASS values, or any port allocation classes.

On our clusters we have a unique ALLOCLASS on each of servers for use with their locally attached devices. It doesn't matter if you already use 1 or 2 as your ALLOCLASS setting.

See the attachment for a sample listing of devices:



Duncan
Bill Hall
Honored Contributor

Re: port allocation class

Gregg,

Fibre channel disks are always allocation class 1, device class DG, controller A. Multipathing set "hide" the any other controllers from you. So all of your fibre channel attached disks will have device names if the format $1$DGAnnnn. Fibre channel attached tape drives are always prefixed with $2$MGA.

Just wait until you try to figure out the conversion between the array's LUN designation and the unit number that the SRM and VMS will see ;-). And then there's the manual configuration of the array's ports and boot device paths with WWIDMGR. And then there's probably something else that I always forget...

Bill
Bill Hall
Hoff
Honored Contributor

Re: port allocation class

FC SAN widgets are $1$ and $2$, as discussed else-thread.

As for the other part of the question, hand-edited files can sometimes trigger parser errors. No two folks ever seem to hand-edit a file in quite the same way, and some edits can sometimes lead to weird and obscure errors during upgrades and ECOs such, or if the file formats change.

I've had a few bad experiences with hand-edited files over the years, and particularly with files and formats that don't have a lint-like verification tool available.

Bill Hall
Honored Contributor

Re: port allocation class

Gregg,

Your storage folks will probably give you a list of LDevs (logical devices) that they are going to present to your cluster. LDev's are comprised of two hex numbers, as in 10:ae. This LDev will be seen by VMS as $1$DGA4270:.
The conversion:
$write sys$output %x10*256+%xae
4270

Bill
Bill Hall
Gregg Parmentier
Frequent Advisor

Re: port allocation class


I've connected it on a free-standing system, so I know the LUN issues and have no problem working with them. I hadn't set any alloclass on the test system, so never thought to look for a default alloclass. I'm also not booting from the SAN. So I think I'm set.

The storage guy was impressed that the VMS 7.3-2 system took less time to get working with the HDS end than solaris or windows. A lot less. Fifteen minutes, vs a few hours. Gotta love VMS.

It's nice to know I don't need to do anything with port alloclass until I put the old SAN out to pasture and just delete the sys$devices.dat file.