Exchange 2010 log location

DEFclub
DEFclub used Ask the Experts™
on
I have my Exch 2010 databases setup on Raid 1 drives and DAG for failover. I have my Tlogs on the same Raid1 drive as the database. I believe Microsoft best practice is to seperate logs onto another volume. Would this be true in my situation or leaving the logs with the DB on RAID 1 for Exchange 2010 is ok?
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Adam BrownSenior Systems Admin
Top Expert 2010

Commented:
Generally, the reason for having transaction logs on a different drive is for a situation where the drive containing the database fails it doesn't also take the transaction logs and you can restore the database to the minute of failure. With a RAID 1, you have some protection from this situation because the database and logs are being mirrored. It isn't an optimal solution, but it will be okay if you can't add an additional RAID 1 to separate the database and logs.

Author

Commented:
what would happen if the partition that holds the logs failed?
Adam BrownSenior Systems Admin
Top Expert 2010

Commented:
You would have to run a repair on the Database to clean it up, then remount it. The logs contain a record of all transactions that have occurred since the last full backup. The data in the logs has usually already been committed to the actual database, but is stored in the logs for redundancy in case the database fails and the last full backup has to be restored. So if the logs drive fails, you don't really lose any data, but Exchange will shut down and the database will go into a dirty shutdown state, which has to be repaired with eseutil.
Success in ‘20 With a Profitable Pricing Strategy

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden using our free interactive tool and use it to determine the right price for your IT services. Start calculating Now!

Author

Commented:
1 last question, If the log partition failed in Exch 2010 and your running DAG, would the databse then failover to the redundant database and the log shipping/seeding tlogs still be intact, thus avoiding a DB shutdown?
Senior Systems Admin
Top Expert 2010
Commented:
In a DAG setup, all transaction logs are sent to the database copy server and applied when the passive node takes over, but whether or not the copy is an exact copy of the active database depends on whether or not the copy is lagged or not. If the secondary is a Lagged database copy, the active server will wait until the lag period is up before sending data and logs to the passive node. This can potentially lead to lost data. If no lag is set up, the two members of the DAG should be as up to date as possible, and the database copy should load up without needing to have transaction files, though they are replicated. Also note that this is only the case if there are only two nodes in a DAG. In a three node DAG (or greater), all the databases are configured for circular logging automatically because of the high level of redundancy inherent in a three node DAG.

Author

Commented:
great thxs

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial