topic Re: Multi-OS Migration and EVA CA in Disk Enclosures

Multi-OS Migration and EVA CA

Anovo — Fri, 06 Feb 2009 17:45:47 GMT

Hello,

We’re about to change our EVA for a brand new one. We’ve already started to migrate windows LUNs, using CA and it has been a rather straightforward process (replication then failover). However, we’ve other servers using different OS (HPUX 11, Solaris starting 2.8 and Linux) I believe those OS do not use disk signature; so is there some additional points we should care about using CA, other than those for windows disks?

TIA

Re: Multi-OS Migration and EVA CA

Uwe Zessin — Fri, 06 Feb 2009 19:16:27 GMT

Those operating systems use some other mechanism to 'tag' a file system or a physical volume that is part of a Logical Volume Manager.

On HP-UX you will most certainly have to deal with new path names after a failover. I don't have any experience with Solaris, but from browsing a manual it looks quite /interesting/. How are your Linux servers connected? Plain ext-file system inside a partition or do you use LVM?

What is the old EVA-model and what is the new model? I assume you are aware there might be updates necessary to the multipath handling (though it sounds like your're covered for Windows already).

Re: Multi-OS Migration and EVA CA

IBaltay — Fri, 06 Feb 2009 19:31:17 GMT

Hi,
in general the UNIX/Linux LVM mirroring can be used for the migration:

for UX its e.g.:
http://docs.hp.com/en/5992-4616/ch03s01.html

more on the continuous access and some aspects of all the OS platforms are here:
http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c01557203/c01557203.pdf

Re: Multi-OS Migration and EVA CA

Anovo — Mon, 09 Feb 2009 09:51:35 GMT

We're moving from a 5000 to a new 4400. All our systems are using LVM, expect the windows ones (cluster) Our SAN zoning is based on WWN, so I was wondering if it was possible to reuse the same WWN with the new disk array. However, I don't know if our systems are using WWN binding - I'm not very familiar yet with Unix O.S.
Does it worth the case migrating LUNs this way, or should prefer using LVM? TIA for your answers.

Re: Multi-OS Migration and EVA CA

Uwe Zessin — Mon, 09 Feb 2009 10:02:32 GMT

You must not reuse a WWN in a SAN as this can cause all kinds of data corruption - this of what a duplicate MAC can do in your LAN. The EVA-4400 will also use a different OUI in its WWN - it could be very confusing (e.g. license-wise) if you reused the EVA-5000's WWN.

WWN-binding is typically NOT used - at least not by default.

If your operating system (setup) allows, migration with LVM is fine. With CA you do need some downtime during the failover and you CAN NOT go back, because you are not allowed to migration from the 4400 to the 5000.

Re: Multi-OS Migration and EVA CA

Anovo — Mon, 09 Feb 2009 10:21:39 GMT

That makes sense, thanks all for your explanations. Weâ ll migrate the remaining LUNs using LVM mirroring feature. Cheers!