We are planning to move our Exchange DB to an EMC SAN (NS-120) with plenty of drive space from our 2007 Exchange server native storage which is getting low on space but not critically low on space (yet).

From what I can find online, a 79Gb Exchange DB is estimated to take roughly 6 to 7 hours. Does anyone concur with this estimate?

I'm prepared to be offline for the time since the DB is dismounted, but I wanted to a rough idea of what to shoot for since I'll be doing it on a weekend between backup windows.

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    Answering this question with any more than shot-in-the-dark accuracy will require details such as what the max sustained sequential read and write specs on the volumes on the server and on the SAN, what the available network bandwidth is and what the disk fragmentation looks like. – JGurtz Apr 4 '11 at 18:58

Can you not bring a new database online on the SAN and move mailboxes to it? My understanding (I stopped working directly with Exchange server when 2003 was new) is that you can mount multiple databases (2003 could) and have some offline and some online.

So, why not simply mount a new database (or do it differently this time and mount a few of them, such that you never wind up with a 79GB single database again) and move the mailboxes to the new database(s)?

  • This is what I would do. 2007 can handle this. This way you can move the mailboxes off-hours one by one and each user is only down for the time it takes to move their mailbox. – pk. Apr 4 '11 at 21:37
  • This is how I would do it. This was good practice back when you were still working with Exchange and it still is now. Especially the bit about splitting the DB up - a 79Gb mailstore isn't the big scary horrible thing it was once seen to be, but I'd still have a few concerns about it. – Rob Moir Apr 6 '11 at 9:02
  • And based on the timing I had with the move, 79Gb isn't all that scary unless you have really slow hardware. The move time was 45 minutes. I will be looking into splitting the DB though, as best practices for Exchange point to not letting the DB get too big (less than 100GB in size). – thinkdreams Apr 10 '11 at 13:09
  • Back in the late 90s and early 2000s, 79GB took a while to restore off tape etc. :) – Mark Allen Apr 11 '11 at 18:25

I had an Exchange 2007 box with a 154GB DB and it took 59 minutes to move to the new location. It is on a virtual box and I moved the DB from one partition on the server to a partition on the same server.


For followup to my own question, I performed the migration on the First Storage Group and Second Storage Group (Public Folders) today. Since I was estimating 6 to 7 hours, I figured a Sunday was best. I did the primary mailbox DB first, at 74 Gb in size (roughly). It took about 45 minutes. Wow. I was surprised. After budgeting for 6 to 7 hours, that was a welcome surprise and reclaimed the rest of my weekend :)

The rest of the storage group (logs and system) for both Storage Groups and the Public Folder Database took about 15 mins.

So all in all it was quicker than expected. For those that sort of asked, I wasn't looking for an exact number, just sort of a ballpark for the timing. Guess we all would have been off :)

I would have to point out that it probably would have been a lot slower had we not spent the good money on the hardware when we bought it. It pays to buy brand name hardware with good performance.

Thanks everyone for your responses. I for one will have a great rest of the weekend. :)

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