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Migrating SQL clusters from VNX to VNX
We have about 20 WS2008 failover clusters all running SQL we need to move to a new VNX. Currently the hosts use MPIO, no PowerPath in place. I've seen that PPME can do this according to bits and pieces on the forums, but is there an actual vetted process documented anywhere which allows these migrations to occur without lengthy downtime? Someone here also suggested Open Replicator or SAN Copy, but I don't see those as being a solution between VNXs. They can't afford much if any downtime, a reboot is about it apparently.
Any direction greatly appreciated.
thanks
dynamox
2 Intern
2 Intern
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20.4K Posts
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November 7th, 2015 13:00
why not SANCopy, cut-over will be a simple matter of shutting down the host, running one final incremental copy, changing zoning and bringing up the system on new VNX. When you setup initial SANCopy session you will set it up as incremental and then you can run incremental copy as many times as you like to keep it "close" to source. SANCopy is very fast, i would strongly consider it versus deploying PowerPath on your all hosts at this point.
umichklewis
1.2K Posts
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November 6th, 2015 09:00
SANCopy is a valid method to move the hosts from one VNX to another, as that's it's intended purpose: moving data between storage arrays.
PPME is also a valid way to move data, and in fact, I highly recommend it. There are procedures in the PPME documentation for moving LUNs in Windows Clusters. I highly recommend going this route, if you have limited opportunities for downtime.
ZaphodB
195 Posts
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November 6th, 2015 09:00
An 'old school' data migration tactic is to connect to the new storage, set up equal sized disks, use OS mirroring techniques to populate them, then break the mirror in favor of the new locations.
I do not happen to know if this is easy/hard/impossible with Windows clustering.
As a storage administrator, this is the sort of thing I used to mention to groups who wanted to be in control of their migration.
Of course, with ESX it is just a live storage VMotion...
downhill2
157 Posts
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November 7th, 2015 03:00
Thanks Karl. PPME does seem to be the ticket, with the only negative probably being the license costs. We are going to weigh the pros and cons of both I think. Last time we used PP around here was years ago, and at that time I don't recall that the migration functionality was there yet, but we may have never looked for it.
downhill2
157 Posts
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November 9th, 2015 05:00
Yes, we are going to weigh the risks and complications around both. The OS team is not opposed to using PowerPath and there are some concerns around how Cluster Manager will handle the disks if we use SAN Copy. I really like the looks of SAN Copy now that I've read into it a bit, we just have never entertained it before I guess.
Question on SAN Copy:
\Is it absolutely necessary to run admhost commands on the clients if all we are doing is getting them synced in the background until such time as a cutover can be made, then completely shutting SQL down and unmounting the drives? I guess I don't see the point or value in doing any quiesce / flush at initiation time for the session since shouldn't all "different" blocks between source and destination LUNs be transferred? When the initial sync finishes, how could there be any difference between the 2?
thanks again.
downhill2
157 Posts
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November 19th, 2015 09:00
We decided, after weighing the options, to go with SAN Copy and it is slick. Sure, it's a rather complex endeavor compared to a host based tool, but, we have the ability to move TB's of data without any sysadmin intervention except for the cutover. It works better than I expected, definitely the way to go when outages are to be kept small along with avoiding licensing or other host driver/filter things. I did answer my own question about the initial quiesce, the documentation needs some clarification but a minor complaint. Admhost is also completely optional.
Anonymous
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274.2K Posts
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April 24th, 2017 03:00
Hi,
Can you please advise if there were some concerns regarding the disk signatures for the clustering
downhill2
157 Posts
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April 24th, 2017 04:00
Nope, Windows cannot tell the difference from old LUN to new if done properly.