storage groups 1 to 1 ratio (Full Version)

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goof1427 -> storage groups 1 to 1 ratio (13.Mar.2008 1:11:05 AM)


first thnx for taking the time to read ...this should be a simple question..

we are migrating to Exchange 2007 soon...the question for storage has come up... we will have 3Mailbox servers and 1mailbox server as standby ...this is will be a SCR cluster...
currently we have exchange 2003..3 servers...each server has 4SGs..with 5mailbox stores...(60mailbox stores)

so if Exchange 2007 with clustering the ratio is one database per storage group i would need 60 storage groups....correct?

Elan Shudnow -> RE: storage groups 1 to 1 ratio (13.Mar.2008 2:02:15 AM)

You only "need" 1:1 ratio where you'll be doing some type of continous log replication; whether that may be via LCR, CCR, and/or SCR.  Even if you're not using continous log replication, it's still recommended to use a 1:1 ratio due to backup/recovery functionality improvements.

For example, if you have 5 databases, if you place all 5 databases in their own storage group, you can back up different databases simultaneously.  If you have 2 databases in 1 storage group, you can back up only 1 of those databases.  In a scenario where your server goes down, you're going to want flexibility in restoration procedures.

Also, Exchange 2007 Enterprise supports 50 storage groups and 50 databases.  Exchange 2007 Standard supports 5 storage groups and 5 databases.  You could get 2 Enterprise licenses or mix and match how you see fit.  As always, Enterprise will be needed for clustering.

Hope that helped.

goof1427 -> RE: storage groups 1 to 1 ratio (13.Mar.2008 8:47:30 AM)

Awesome ...thnx! ...that helps a lot...  another question is that there isnt much written on the subject of 1 to 1...and the reasons why ... like you stated for backups and recoverability... anywhere i can get more info?  thnx. -> RE: storage groups 1 to 1 ratio (13.Mar.2008 9:27:34 AM)

The reasons are wide and varied. When you look on the MS site you'll see the recommendations for the 1:1 relationship and there will be reasons given there. One very good reason for it is performance. If you have lots of stores in one SG you have a lot of logs getting generated. This is bad, very bad if you're one of the 90% of people who ignore disk layout instructions, as you end up with queues, latency, log record stalls and annoying "bubble" messages in Outlook as the clients stall until the server purges the logs out.

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