From: Dave T. (davidlt77@hotmail.com)
Date: Wed Aug 10 2005 - 13:03:47 EDT
Thanks go to the following, in chronological order of when I received
replies:
o John Adams
o Mike Keighley
o Robert Meyers
o Mohan Sundaram
o Bob Vance
o Justin Willoughby
Below is my original post, followed by the responses.
--------------------
Original post:
We need to replace a SureStore 2/20 tape library on the SAN with a Compaq
MSL5060. Our network administrator doesn't want to bother with it until
next week, saying it's will cause him too much work, which is what he says
nearly anytime we need to make changes on the SAN. We use zoning, and stuff
will need to be re-configured on the Brocade SAN switch. I'm no SAN
administrator, but my understanding is that it isn't that difficult to make
the changes. Does anyone know any reason why this would be a laborious
process for the network administrator? If he's right, I need to be
educated, but he has a reputation for blowing smoke, so I can't rely upon
what he says.
Dave
--------------------
Dave,
The answer is, unfortunately, it depends.
If you're zoning by world-wide name (the SAN equivalent of a MAC
address, that is a string that is unique to every adapter) then it's
marginally easier to do the zoning after the new device is connected to
the SAN. Otherwise, you have to key in the WWN, and they can be rather
long.
Call it half an hour per port for the actual work worst-case, but that's
just the switch. There may be backup software involved, there will be
the matter of drive locking, i.e. how does this server know that server
has that device in use?
You may need to stop work on the MSL5060, depending on how well it will
react to seeing new servers.
It is potentially a bad job, but it really depends on exactly what
you're asking this guy to do, and what he realizes he needs to do that
you don't know about yet.
Good luck!
J
--------------------
I would imagine that, not only does he have to re-zone the switches for
the WWN of the new device, but then every device/program which
communicates with it will need to re-detect it. This could be as simple
as one centralised backup program going through its "new device" wizard,
or if serverless-backup is used, it could be re-configure or even re-boot
every server.
Mike.
--------------------
If you are zoning - and use wwn's all you need to do is remove the old
wwn and replace it with the new wwn - re-enable and save the configs -
If you are port zoning - there should be no change at all....
-Robert
--------------------
HI Dave,
If you are just removing the surestore and adding the MSL in the same
switch port, there is nothing to change as far as the zoning is
concerned, unless you want to give the name of the zone differently.
If you want to add some additional servers to the backup zone then
additional zone configuration is required. But the zone config itself
may not be more than few minutes,so 30 minutes of downtime (maximum) for
that switch is what is required.
If you have all your hosts connecting to dual fabric and multipathing
softwares installed, you need not worry about the downtime of 1 switch.
Perform the activity at a time when no backup is about to start. That's
the only impact.
With regards,
Mohan.
--------------------
Well, let's suppose that he's using WWN zoning and needs to re-use the same
port.
Then, a safe way to do it would be:
Every zone with the tape will have to be changed to remove the current tape
WWPNs or zone aliases.
Then the Brocade config will have to re-enabled.
Then the tape removed and replaced by the MSL.
Then every "tape" zone above will be updated again with the WWPNs (or a zone
alias)of the new device.
Then the Brocade config re-enabled, again.
It can be time-consuming when you're being very careful and have lots of
tape zones -- but no more than a few hours.
Of course if there are not many zones with the tape, then it's not too bad.
--------------------------------------------------
BV <mailto:BobVance@alumni.caltech.edu>
Sr Technical Consultant
Storage, Networking, HP-UX, Linux
Inplexus - a Cnetics group
7076 Peachtree Ind. Blvd. Office 404-446-0404
Norcross, GA 30071 Fax 801-327-6152
Home Office 770-977-3476
==================================================
--------------------
Zone changes can be a bit complicated depending on the size of the zone
and how the zoning is done, port based vs node name based, etc. We have
two separate fabrics for redundancy and it probably takes less then 30
minutes per fabric but we make changes to each on different dates in
case something goes really wrong. It's more of a pain then time
consuming to make zone changes.
- Justin
==================
Justin Willoughby
Computer Operations
==================
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