SAN and Clustering

[Catadmin]

Hello.

I didn't see this question previously answer on this forum, so I though I'd post it. I've just gotten hired as a DBA for a company. They want to implement SAN and RAID for their database servers. Previously, they attempted to implement clusters, but apparently the Network Admin has never done it before, so he gave up on the project. Now I'm being asked to take over.

I've been doing research on the internet and found a document from Microsoft talking about SANs and Clusters as if both should be used together. My question is, does SAN *have* to be used with Clustering? If not, what are the ramifications of not Clustering? I guess I'm looking for an experience based pro & con list on this issue.

Most of the software we use is either Microsoft related or in house developed (including SQL Server & Windows 2k / 2k3 Server). I don't know if you need to know that. And we don't have the hardware yet. We've just started talking to sales reps.


Thanks to everyone for their assistance in advance.





Catadmin - MCDBA, MCSA
Beware the error of pre-emptive poultry inventory!

 

[comtec17]

You do not need a SAN to cluster. All you need to have is a Disk unit that can be shared between 2 or more hosts.

On "DAS - Direct attached Storage" some units come with multiple SCSI buses to share the disk down.

A SAN is a good option if you need to have fast access to the disk. Using SCSI, you are limited by distance. While using SAN you gain distance and performance (depending on setup).

If your Database is very heavily written to a RAID 1/0 setup is the best option.

Hope this helps.

 

[SanWizard]

I agree with comtec17. In addition, regardless if you use a shared disk array or disk within a SAN....be sure to isolate your log LUN's from your database LUNs. This will eliminate disk contention between the two. By isolation, I also mean separate physicals. (No disk stacking)