topic Re: Will replaing a san switch is going to change CTD of existing Disks in Operating System - HP-UX

Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Thu, 07 Sep 2006 11:31:48 GMT

Folks,

We are planing to replace an existing 32port SAN switch with a 64port switch. All zoning and port map settings will remain same like the old one.

Will this change is going to affect the existing CTD numbers of the disks.

We wanted to avoid the complex task of reimporting all volumes groups.

System : HPUX 11.11
HBA : TACHYON
Storage: EMC Symmetrix
OLD SAN Swith : MCData ED1032(32Port)
NEW SAN Switch: MCData ED64M (64Port)

Please advise.

Thanks, Sunil

Re: Will replaing a san switch is going to change CTD of existing Disks

Steven E. Protter — Thu, 07 Sep 2006 11:54:06 GMT

Shalom Sunil,

With almost certainty, your devices will change when you make the switch.

It is possible to renumber the instances after the fact and get them back to what you wish. The procedure for this in HP-UX is non-trivial.

Links:
http://www.google.com/url?sa=t&ct=res&cd=2&url=http%3A%2F%2Fforums1.itrc.hp.com%2Fservice%2Fforums%2Fquestionanswer.do%3FthreadId%3D1053791&ei=ZE4ARY2QB5n6ggO2kZC7CQ&sig=__lEVJnHZurNcaI3noMup7T07fxO0=&sig2=r41DTtjOQv54ptTbvpEcSg
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1014733

SEP

Re: Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Thu, 07 Sep 2006 12:32:00 GMT

Hi,

I agree with you! But I am looking for some soltution which will not change the CTD nos.

Is there any way we can make it. If CTD no changes, I have hell lot of work to do. This is very complex environment with BCV and Standard devices are in the same server. And offcourse more than 100 Vgs spred across 9 Nodes...
OOps...

Thanks, Sunil

Re: Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Thu, 07 Sep 2006 14:56:40 GMT

Folks,

Here is my setup, can any one tel me what will happen if I isolate CNX01 from the SAN and attch CN03 diretly to the storage. Is my CTDs going get changed.

What is the Remote Nport ID for any given hosts, with the existing setup?

Regards,
Sunil

Re: Will replaing a san switch is going to change CTD of existing Disks

Kevin Wright — Thu, 07 Sep 2006 16:49:56 GMT

Probably not, however I would ensure you get map files for all you volume groups, with the -s option.

Then even if they do change, all you have to do is vgexport, and vgimport -s each volume group.

Re: Will replaing a san switch is going to change CTD of existing Disks

Kevin Wright — Thu, 07 Sep 2006 16:51:35 GMT

Not sure if you have a test/dev environment to test first? if not, be prepared for the worst case scenario for sure.

Re: Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Thu, 07 Sep 2006 17:01:58 GMT

Hi Kevin, I am sorry that I missed to reply for your suggestion.

We have BCV copies inside the same box, which will mess up if use vgimport with "-s' option.

Sunil

Re: Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Mon, 11 Sep 2006 11:40:22 GMT

Folks, do you guys have any more idea how to make it.

Thanks, Sunil

Re: Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Wed, 13 Sep 2006 10:14:00 GMT

I am planing to close this thread, since I am not getting any helps.

Re: Will replaing a san switch is going to change CTD of existing Disks

likid0 — Wed, 13 Sep 2006 10:35:29 GMT

I did the same thing a couple of weaks ago, we changed the san switch and all the devices names changed, where i was using sdd, there was no problem, with a cfgvpath all was ok, were a i wasnt i did the usual import export.

not a lot of help but just to let you know

Re: Will replaing a san switch is going to change CTD of existing Disks

IT_2007 — Wed, 13 Sep 2006 11:21:31 GMT

Sunil,

It is not possible to do this in a simple way. Either you need to import all volume groups reflecting change or change instance numbers for controllers to have same device names.

Since you said there are lot of vg's spread across nodes, better write a generic script will read vg's from /etc/lvmtab and store corresponding maps and LUN info.

Re: Will replaing a san switch is going to change CTD of existing Disks

Sยภเl Kย๓คг — Wed, 13 Sep 2006 12:03:44 GMT

Hi,

I have a major concern about the downtime also.

Thanks, Sunil