Clustering Vs Mirroring

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Clustering Vs Mirroring

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ianT SSCrazy Points: 2956 More actions · Answer 1

Hi

I'm starting to look at mirroring to provide failover. Am trying to avoid clustering as I have had problems setting it up and maintaining it.

However, we are thinking to use virtual machines to achieve the same result. In this scenario, we can build a VM with its own filestore and mirror data to it or create a VM pointing to the production server filestore (the filestore is on a SAN so should not fail). Either way failover is seamless (or so I'm told).

Has anyone used VMs for this sort of application?

2Tall SSChampion Points: 14644 More actions · Answer 2

Thanks guys. That explains why the consultant wants to mirror. Never considered a SAN for a shared disc array as I have never worked with SAN's. How does it tie in with the servers running SQL? Is the OS + SQL installed on the local drives then Data / Logs etc stored on the SAN?

Phil

PS: Servers have P400 SCSI Controller 512MB not the Ultra 320.

storport driver

Going off track here but backup has failed miserably (hardware failure) since I moved it to Windows Standard R2 64 BIT (Drive Ultrium LT03 Storageworks 960). On dedicated SCSI controller. Someone mentioned problems with the storport drivers? Maybe one for another forum!! 🙂

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Matt Miller (4) SSC Guru Points: 124210 More actions · Answer 3

Philip Horan (11/28/2007)
Thanks guys. That explains why the consultant wants to mirror. Never considered a SAN for a shared disc array as I have never worked with SAN's. How does it tie in with the servers running SQL? Is the OS + SQL installed on the local drives then Data / Logs etc stored on the SAN?
Phil

Correct - that's about it.

There's also a portion of the registry that is synchronized between the two instances (various SQL-related keys).

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Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?

alen teplitsky SSC-Dedicated Points: 30014 More actions · Answer 4

Philip Horan (11/28/2007)
Thanks guys. That explains why the consultant wants to mirror. Never considered a SAN for a shared disc array as I have never worked with SAN's. How does it tie in with the servers running SQL? Is the OS + SQL installed on the local drives then Data / Logs etc stored on the SAN?
Phil
PS: Servers have P400 SCSI Controller 512MB not the Ultra 320.
storport driver
Going off track here but backup has failed miserably (hardware failure) since I moved it to Windows Standard R2 64 BIT (Drive Ultrium LT03 Storageworks 960). On dedicated SCSI controller. Someone mentioned problems with the storport drivers? Maybe one for another forum!! 🙂

we have 3 instances on 2 clusters on an EMC SAN

part of the program files are on c drive on each server and most of the SQL program files are on common storage on the SAN along with all the databases. one server has access to the disks at a time and a failover is simply one host giving up control to another.

it's not 100% perfect and we had it where an instance goes down with no failover. i will take mirroring for major DR to another site. we do it via EMC now to another SAN in another city and mirroring is just cheaper. but if it breaks and you have to run a full restore across the WAN and it goes down then you are screwed.

consultant is probably a microsoft shiny gold partner or something similar and this is why he has to push mirroring.

2Tall SSChampion Points: 14644 More actions · Answer 5

Thanks Guys.

Phil

-------------------------------------------------------------------------------------
A neutron walks into a bar. "I'd like a beer" he says. The bartender promptly serves up a beer. "How much will that be?" asks the neutron. "For you?" replies the bartender, "no charge."

Two hydrogen atoms walk into a bar. One says, 'I think I've lost an electron.' The other says 'Are you sure?' The first says, 'Yes, I'm positive... '

Tommy Cooper

noeld SSC Guru Points: 96590 More actions · Answer 6

And one more thing that people have not mentioned about clustering is not the individual parts but the "entire" system what should be cluster-certified!!!

* Noel