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Single vs Multiple Exchange Database file

sglee
sglee asked
on
Hi,
 
 I have Exchange Server 2010 with a single mailbox database with about 30 mailboxes and file size is 230GB.
 Recently it crashed, failed to mount and I had to repair exchange database. Even after I got it mounted, due to some corrupted mailboxes, I ended up creating a second mailbox database and moved some mailboxes from original database into newly created database.
I have not thought about this, but I am thinking that it may be a good idea to split these 30 mailboxes into several mailbox database files in stead of a single file.

Here is my thought:

First, when I have to perform a database repair, it would take less time.
Second, when the computer loses the power, corrupting exchange database files, there is a chance some files might be in good shape.

However since I have not managed multiple exchange database files, I like to listen to other experts about Pros and Cons.

Thanks.
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Tom CieslikIT Engineer
Distinguished Expert 2017
Commented:
It's completely normal.
I have 200 mailboxes in my organization and I've split them between 5 databases. (40 mailboxes each)
Simple job, just create another database and move mailboxes one by one using  ECP or Powerschell script.
Very smart move and failsafe decision
Lee W, MVPTechnology and Business Process Advisor
Most Valuable Expert 2013
Commented:
For such a small number of mailboxes, it's not necessarily recommended.  However, splitting the database up provides:

1. Faster times to repair when a database needs repair (as you've mentioned).
2. Potentially faster backups and depending on how you lay them out on the disks, it may help minimize performance issues.

But I think your logic is flawed when it comes to your second point - Yes, there a chance some files might be in good shape... there's also a GREATER chance some files WON'T be in good shape.  The more you have, the more you have to worry about.

I'd ask you WHY is the computer losing power? A $100 UPS connected to your host server (this IS a VM, right?) can gracefully shut everything down or at least "save" them so if you lose power, you don't corrupt things... That's an even better idea in my opinion, especially if you don't have it already!

Author

Commented:
Computer has a UPS. However it got locked  up for unknown  reason and I could not get to desktop screen to shut it down properly; therefore I had no choice but to hold power button down.
Lee W, MVPTechnology and Business Process Advisor
Most Valuable Expert 2013

Commented:
And what postmortem have you done to determine why that happened?  It's not always easy or even possible to tell... but you need to look at your system and try to understand why it's not performing as it should.  Make sure your backups are good.  Things will happen... BUT, this should not be a common occurrence... if it's anywhere near a common thing, you need to take steps to prevent it before you start breaking up the exchange database (not saying it's a bad idea - or a good idea - but rather an idea that should be addressed LATER).
Tom CieslikIT Engineer
Distinguished Expert 2017
Commented:
Next time try to run remote shutdown /r /m \\emailserver /f /t 5  command from other server /workstation

Author

Commented:
@Tom
I would have tried remote shutdown had I known this command then. I will try it in the future.
@Lee
I did not get a chance to save event viewer log immediately after the server freeze due to many issues that I had to address.
Since I did not increase the size of event files from default - 1024, the events that I could have looked for are gone by now. It has been 10 days.
On the day of freeze, I stopped windows server backup to preserve the previous day of good exchange backup just in case I need to restore exchange database. On the 2nd day I resumed the backup.
If it is possible, I could try to restore event viewer as of next day of freeze to see what I can find.
MaheshArchitect
Distinguished Expert 2019

Commented:
as long as you are having single mailbox database server, no matter how many databases you create, it won't help since server crash will affect all databases
For 30 mailboxes I wouldn't recommend 2nd server in DAG for HA to avoid outage and issues, but that could be an option
Probably you can check suitable O365 plan and move your mailboxes, it will be better option as far as I think
Microsoft recommends that the database size should not be more than 200GB in size.
https://blogs.technet.microsoft.com/exchange/2009/11/09/exchange-2010-server-role-requirements-calculator/

Author

Commented:
@Lee
“And what postmortem have you done to determine why that happened?” —> Not sure 100%, but I found out that an old external USB HD has gone bad beyond repair via Seatools.
I had it unplugged (when I powered the server off ) until few days ago. When I finally plugged it back to the server, it only displayed the drive letter and failed to display capacity and free space information. That is when I brought it to my computer and ran Seatools & teied “Fix-all” option (but failed to fix).