[HPADM] RE: RE: SUMMARY: How to Mirror Disks to VA & Then Remove Old Disks
From: Dave T. (davidlt77_at_hotmail.com)
Date: 09/19/03
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To: BVance@sbm.com Date: Fri, 19 Sep 2003 09:49:19 -0400
Thanks, Bob!
Dave
----Original Message Follows----
From: "Bob Vance" <BVance@sbm.com>
Reply-To: <BVance@sbm.com>
To: "'Dave T.'" <davidlt77@hotmail.com>
Subject: RE: [HPADM] RE: SUMMARY: How to Mirror Disks to VA & Then Remove
Old Disks
Date: Fri, 19 Sep 2003 09:19:28 -0400
It should be noted that performance, when using most of the space, is based
on your usage of the space. You could have performance issues with any
allocation up to ~50%.
By default, the "available" (allocable) space is structured such that a
minimum of 10% will be in RAID 1 (+0 ; mirroring(+striping)), even when you
allocate "all" of the "available" space. If your "active write set" (data
that is changing) is greater than the 10% of your space, then the array will
be forced to rewrite some data into RAID5 so that the most recently written
data can go into RAID1.
However, the same thing applies basically to any percentage. If you
allocate less space, leaving say room for 20% of the data to be mirrored,
but your active write set is greater than 20%, then you have the same issue.
Of course, you can allocate only 50% of the space and then everything will
be in RAID1 and none will have to go into RAID5, but there are cheaper ways
to mirror :)
---------------------------------------------------------
Tks <mailto:BVance@sbm.com>
BV <mailto:BobVance@alumni.caltech.edu>
Sr. Technical Consultant Vox 770-623-3430
Arrow Electronics, Inc. Fax 801-327-6152
Enterprise Computing Solutions
SBM Division
11455 Lakefield Dr.
Duluth, GA 30097-1511
=========================================================
-----Original Message-----
From: hpux-admin-owner@DutchWorks.nl
[mailto:hpux-admin-owner@DutchWorks.nl]On Behalf Of Dave T.
Sent: Friday, September 19, 2003 8:00 AM
To: Mike.Pappenheim@edfenergy.com
Cc: hpux-admin@DutchWorks.nl
Subject: [HPADM] RE: SUMMARY: How to Mirror Disks to VA & Then Remove
Old Disks
Thanks, Mike. I'll look into those things.
Dave
----Original Message Follows----
From: "Pappenheim, Mike" <Mike.Pappenheim@edfenergy.com>
To: "'Dave T.'" <davidlt77@hotmail.com>
Subject: RE: [HPADM] SUMMARY: How to Mirror Disks to VA & Then Remove Old
Disks
Date: Fri, 19 Sep 2003 09:36:29 +0100
Dave,
I have been using a VA7410 and you should also be aware of a few things if
you want to avoid performance problems.
1) The default PV timeout when you have pvcreate your disks is 30 seconds
and that seems not to be enough for VA7410 LUNs when the system is busy. I
always do a pvchange -t 240 /dev/dsk/cxxtxdx on all my VA LUNs or else you
are like to see timeouts in your /var/adm/syslog/syslog.log.
2) Each Host F/C port on the VA has a queue full threshold setting which
defaults to 750. This is much too high. We set ours to 45 using
armmgr -q 45 {fru_id} {array_id}, where fru_id is M/C1.H1 etc
3) We made the mistake of allocating all the space in each Redundancy Group
to LUNs. We subsequently found that the performance is dreadfull unless you
leave many GB of unalocated space so that AutoRaid can use this as RAID 1/0
space. We now leave at least 50GB unallocatad in each RG.
Hope this helps.
Regards
Mike
> -----Original Message-----
> From: Dave T. [mailto:davidlt77@hotmail.com]
> Sent: 18 September 2003 15:28
> To: hpux-admin@dutchworks.nl
> Subject: [HPADM] SUMMARY: How to Mirror Disks to VA & Then Remove Old
> Disks
>
>
> 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,,0x520f31ec5e34d
711abdc0090277a778c,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 _________________________________________________________________ Get 10MB of e-mail storage! Sign up for Hotmail Extra Storage. http://join.msn.com/?PAGE=features/es -- ---> Please post QUESTIONS and SUMMARIES only!! <--- To subscribe/unsubscribe to this list, contact majordomo@dutchworks.nl Name: hpux-admin@dutchworks.nl Owner: owner-hpux-admin@dutchworks.nl Archives: ftp.dutchworks.nl:/pub/digests/hpux-admin (FTP, browse only) http://www.dutchworks.nl/htbin/hpsysadmin (Web, browse & search) **************************************************************************** *************************** EDF Energy plc internet e-mail disclaimer This e-mail and any files transmitted with it are confidential and may be protected by legal privilege. If you are not the intended recipient, please notify the sender and delete the e-mail from your system. This e-mail has been scanned for malicious content but the internet is inherently insecure and EDF Energy plc cannot accept any liability for the integrity of this message or its attachments. No employee or agent of EDF Energy plc or any related company is authorised to conclude any binding agreement on behalf of EDF Energy plc or any related company by e-mail. All e-mails sent and received by EDF Energy plc are monitored to ensure compliance with the company's information security policy **************************************************************************** *************************** _________________________________________________________________ Get 10MB of e-mail storage! Sign up for Hotmail Extra Storage. http://join.msn.com/?PAGE=features/es -- ---> Please post QUESTIONS and SUMMARIES only!! <--- To subscribe/unsubscribe to this list, contact majordomo@dutchworks.nl Name: hpux-admin@dutchworks.nl Owner: owner-hpux-admin@dutchworks.nl Archives: ftp.dutchworks.nl:/pub/digests/hpux-admin (FTP, browse only) http://www.dutchworks.nl/htbin/hpsysadmin (Web, browse & search) _________________________________________________________________ Compare Cable, DSL or Satellite plans: As low as $29.95. https://broadband.msn.com -- ---> Please post QUESTIONS and SUMMARIES only!! <--- To subscribe/unsubscribe to this list, contact majordomo@dutchworks.nl Name: hpux-admin@dutchworks.nl Owner: owner-hpux-admin@dutchworks.nl Archives: ftp.dutchworks.nl:/pub/digests/hpux-admin (FTP, browse only) http://www.dutchworks.nl/htbin/hpsysadmin (Web, browse & search)
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