Exchange 2007 LCR on a Drobo!
Exchange 2007 has a great new technology referred to as ‘Local Continuous Replication’. Basically it is the ability to locally replicate all exchange logs and databases to another storage device (in this case a drobo), another partition, or a different server altogether.
What is it?
It is simply an in-built capability in Exchange that copies/replicates all databases and exchange log files to another partition/device.
Why use it?
This capability allows you to feel a little bit better knowing that should your main partition with all of your exchange data get corrupted, you can switch to the LCR data and be up and running very quickly. This reduces down time and gives you the ability to restore the original hardware that the database and logs are stored on.
What did you use?
We had a need for this ability and thus decided that we would explore many different options. This was being designed for a small/medium business and thus cost was a priority. We decided to buy a 2nd generation Drobo, load it up with 4x500gb drives and start the replication process, all via USB 2.0 on our server. The total cost was less then $1,000 and the value was priceless.
How is the speed?
The speed of the replication will initially depend on the size of your Exchange databases and when you last took your backup. Exchange 2007 truncates all log files after it detects a successful backup and thus you should do a full backup before attempting to set up LCR. Once this is completed the size of data being replicated to the Drobo will be smaller and thus will reduce wait times. We used this with a 190gb Exchange database and our LCR time (initial replica) was about 40 minutes or so….once it has replicated once it will continue to replicate changes regularly and is on the fly. No delays.
What about Exchange Backups?
Exchange backup’s are very sensitive, as you are probably aware by now. Using a Drobo with LCR makes them even more sensitive. The backup software that we use is Symantec Veritas Backup Exec 12.x. In BE you must specify if exchange will backup from the Passive (LCR) copy or from the Active copy. There are options that will try the passive copy first and fail back to the active copy. We have found that directly backing up the active copy directly works the best with the Drobo. The reason for this is that exchange is replicating to the Drobo over USB, therefore, if the backup tries to use the Drobo simultaneously, a USB bottleneck gets created causing the backup to fail. Backup the active copy and it works flawlessly and updates the LCR copy on the Drobo.
The Drobo is an excellent storage device that allows for a ‘robotic’ raid storage in which you can use any spare SATA drives to create a storage library. When researching for something in this price range, we found that nothing came close…especially with this type of technology. We are now using Drobo’s on 3 Exchange 2007 servers and can sleep better at night knowing that we are protected.
More info on the Drobo is located at http://www.drobo.com
