From: Dave T. (davidlt77@hotmail.com)
Date: Thu Sep 18 2003 - 10:28:18 EDT
For everyone who responded, thank you very much for your input! I
appreciate that you took the time to provide an answer.
My original post is at the very bottom. Following are all the replies I
received, which include a variety of opinions and methods, listed in the
order in which I received them:
****************************************************************************
>From : "Paveza, Gary" <gary.paveza@AIG.COM>
To : "'Dave T.'" <davidlt77@hotmail.com>
Subject : RE: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 13:47:59 -0400
You don't mirror disks in HPUX, you mirror logical volumes. All you need to
do is add disks from the VA to the volume group which contains the logical
volumes to mirror. Extend the logical volumes with the -m option to those
disks. Give it time to sync (lvdisplay -v) then reduce the logical volume
with the -m option from the old disks. Reduce the disks from the volume
group and you're done.
---------------------------------------------------------
Gary Paveza, Jr.
Senior Systems Administrator -CSA
(302) 252-4831 - phone
(302) 377-1516 - cell
****************************************************************************
>From : "Scalone, Galen" <Galen.Scalone@vacationclub.com>
To : "'Dave T.'" <davidlt77@hotmail.com>
Subject : RE: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 13:53:32 -0400
Dave,
Once the new disks are available to the server, meaning they have been
connected, and you see the device files, add them to the volume group in
question. Mirror all of the logical volumes to the new disks (lvextend -m 1
/dev/vgXX/lvolXX /dev/dsk/newdisk). Then remove the original mirror copy.
(lvreduce -m 0 /dev/vgXX/lvolXX /dev/dsk/olddisk.)
Some things to whatch out for: Make sure you can add disks to the volume
group. There is a default setting of 16 physical volumes per volume group,
unless you use the -p option. If you can only add a few disks, and they are
the same size as the original disks, look into pvmove. That will actually
let you move physical extents fron one disk to another.
If you need more details, let me know.
Galen
****************************************************************************
>From : "Manuel Abellan" <mabellan@pcdsolutions.com>
To : "Dave T." <davidlt77@hotmail.com>
Subject : RE: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 14:03:13 -0400
Hi Dave:
I don't have a document that details what you need although I have done that
type of migration several times. Every setup is a little different but
amongst others, the steps you need to take in consideration are:
- Physical setup to make sure the system(s) can see the Symmetrix at the
same time they see the VA7410. SAN setup etc.
- Define a migration strategy depending on how the VGs were created, may
times the max PE per PV forces you to match the biggest disk(lun) in the
vg(instead of defining bigger ones), if this is not a limitation you can
consolidate several luns into a bigger one when you have a lot of disks in
one vg. max pv in a vg can be an issue too.
- Consider the number of LUNs for the VA7410, redundancy groups, number of
LUNs for security, queue depth etc.
- I prefer lvextends to pvmoves to let the system run for a couple of
days(hours) with the LVs mirrored before lvreduce the Symmetrix side. Do one
VG at a time to prevent big impacts on performance, you can schedule the
mirrors in less busy hours.
- It is a good idea to run collect tools like nickel to produce a documented
view of the VGs and LVs, this will force you to discover the present view of
the system to be able to catch any inconsistency with your present system(s)
like vgs in lvmtab but not mounted, serviceguard vgs etc.
- Create a dumb vg on the symmetrix and mirror it on the VA if you have
space, to have a proof of concept and test your scripts/procedure before
messing with production data. When everything goes well you can do pretty
much all the migration without any downtime.
Hope these steps will help you get started.
Manuel
****************************************************************************
>From : "Whittemore, Dale" <dale.whittemore@lmco.com>
To : "Dave T." <davidlt77@hotmail.com>
Subject : RE: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 12:06:16 -0600
If you have a license for the MirrorDisk/UX product, you can find out
how to mirror on pages 397 - 406 of the Managing System and Workgroups:
A Guide for HP-UX System Administrators manual online in both PDF and
HTML formats at http://hp.docs.com.
The direct link is:
http://www.docs.hp.com/hpux/pdf/B2355-90742.pdf for the pdf file
or
http://www.docs.hp.com/hpux/onlinedocs/B2355-90742/B2355-90742.html for
the html version.
Dale A. Whittemore
Computer Systems Analyst, Senior
Lockheed Martin Enterprise Information Systems
Denver, Colorado
****************************************************************************
>From : "Abramson, Stuart" <SAbramson@Wabtec.com>
To : "'Dave T.'" <davidlt77@hotmail.com>
Subject : RE: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 14:30:59 -0400
We did a big migration once, and we shut down and copied the data. Here's
why:
1. pvmove, or extending mirrors from once disk to another modifies the
VG/LV structure, and isn't easy to develop a backout/contingency plan for.
2. Copying the data to new LVs allows you to restructure and plan for
new growth, etc, such as increasing each LV by 20%. If you mirror, you
can't do that; the mirrors must be equal sizes.
Do some timing studies and compare. pvmove is the slowest, and has NO
backout at all. It's just plain dumb.
The downside to copying is: you have to shut down to get a consistent
snapshot of your database. If it's big, you can be down for an entire
weekend.
Whatever you do, do a trial run first. On a small DataBase.
Also, write up a plan in advance, on paper. And think about it.
If you insist on mirroring, here are some commands:
cLEFT=c4t6d0 # 1/0/0/3/0.6.0
cRIGHT=c7t6d0 # 1/0/1/0/0/1/1.6.0
vgextend vgXX /dev/dsk/${cRIGHT}
vgdisplay -v vgXX | grep "LV Name" | awk '{print $3}' | while read
LV
do
lvextend -m 1 $LV /dev/dsk/${cRIGHT}
done
Stuart Abramson | Off: 412/825-1434 | Cell: 412/417-1567 | email:
sabramson@wabtec.com
****************************************************************************
>From : Tim.Pickel@rrd.com
To : davidlt77@hotmail.com
Subject : Re: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 15:01:42 -0400
There's nothing magical about mirroring VA disks or EMC disks. Use the same
mirror commands
EMC disks = cXtXdX
VA7410 disks = cYtYdY
pvcreate /dev/rdsk/cYtYdY
vgextend /dev/vg?? /dev/dsk/cYtYdY
lvextend -m 1 /dev/vg??/lv?? /dev/dsk/cXtXdX /dev/dsk/cYtYdY
lvreduce -m 0 /dev/vg/lv /dev/dsk/cXtXdX
|----------------+-------------------------+------------------------|
| | | |
| (Embedded | Tim N. Pickel | email: |
| image moved | Unix Systems | tim.pickel@rrd.com |
| to file: | Administrator | Office: (717) |
| pic08313.gif) | RRD Financial | 391-5562 |
| | 53 West James St | Mobile: (717) |
| | Lancaster, PA 17603 | 629-6878 |
| | | Fax: (717) |
| | | 391-5666 |
| | | |
|----------------+-------------------------+------------------------|
****************************************************************************
>From : "Rita Workman" <RWORKMAN@wvbep.org>
To : <davidlt77@hotmail.com>
Subject : Re: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 15:18:05 -0400
Well I had to migrate data from an old EMC to a new EMC...maybe some of
the things mentioned in this thread will help you.
Best Wishes on your migration,
Rita
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x520f31ec5e34d711abdc0090277a778c,00.html
****************************************************************************
>From : "Ford, Phillip" <phillip.ford@spcorp.com>
To : "'Dave T.'" <davidlt77@hotmail.com>
Subject : RE: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date : Wed, 17 Sep 2003 15:34:41 -0400
We used the pvmove command. It worked find. It does a mirror of one LP at
a time and then breaks it. Note: send the command to the background (I used
at) so if your terminal session is broke it keeps running. I had one break
due to a timeout and I had to call HP to clear it. No lost data but it left
the funny one lp mirror.
Hope that helps
--
Phillip Ford
Senior Software Specialist
Corporate Computer Center
Schering-Plough Corp.
(901) 320-4462
(901) 320-4856 FAX
phillip.ford@spcorp.com
****************************************************************************
----Original Message Follows----
From: "Dave T." <davidlt77@hotmail.com>
To: hpux-admin@dutchworks.nl
Subject: [HPADM] How to Mirror Disks to VA & Then Remove Old Disks
Date: Wed, 17 Sep 2003 13:37:23 -0400
Does anyone have a doc that details how to mirror disks to a VA and then
remove the old disks? We are migrating data from an EMC Symmetrix to a
VA7410. Once the migration is complete, we will disconnect the Symmetrix.
Thnx,
Dave
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