Recommendations for splitting up Exchange 2003 Information Store on Single Disk Subsystem

I have a Windows Server 2003 R2 server running Exchange Enterprise 2003.  The server is built with one RAID5 array.  I currently have one Storage Group with one Mailbox Store that is now over 400GB.  My backup is taking almost 8 hours.  My questions:  

1.  Is there any reason to divide this one SG and MS other than backup and restore times?
2.  If the resommendation is to split them up, what is the benefit of having multiple SCs over multiple MSs?  I know I can have four MSs withinin each SG.  Should I max out the four MSs before I create a new SG?
3.  Since all the bays in my server are already maxed out, creating a second array isn't an option at this time but if I was to buy a new server, what would be your recommendation on configuring it?

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MesthaConnect With a Mentor Commented:
The problem you are going to have is that you really need to split the database in two completely separate databases. Do you have enough space to do that?
If you don't do that you will have a 400gb store with a lot of white space in it. While you could do an offline defrag to reduce that, that would require ~500gb of space to do so, and a very long period of downtime.

On a single RAID 5 array you are going to be getting poor performance as well, particularly on a store of that size.

External storage is going to have to be used to get things to move at any decent rate. I would actually be looking at whether there is any way that the box can be rebuilt so that the storage can be optimised. I hate to think what your disk IO is like.

As for the benefits, it mainly comes down to DR. By keeping things at about 50 - 100gb the SLA for restoration of the store is quite reasonable. You would only need to keep enough free space to restore one set, rather than the entire database as you are now.
Performance gains will be negligible, I would actually say you would take a performance hit on the current storage with multiple mailbox stores (so taking things from bad to worse) because rather the storage having to write to just two locations at the same time, it could be four or more (depending on how many additional storage groups you create).

When it comes to backups, do make sure that you are only backing up the information store and nothing else, although eight hours would be very quick if it was more than just the store.

Being blunt, the entire storage structure needs to be revised, there is little that you can do to improve things with your current setup, radical changes will be required.

mickeyfanConnect With a Mentor Commented:
We are using multiple storage group with multiple DB's in each storage group. The main reason we do this is because if you have one store and that DB fails your whole company is with out. I know that if the server fails the same thing happens.
But if you split up the company into separate Stores then you are decreasing the risk of a full outage. There is another reason as well. If you look at your 400GB store and use eseutil and determine how fragmented it is i am willing to bet you that you have prob a 25% growth of you database that is none usable data. If you split this then you fragmentation will decrease and decreasing unused space.

As far as backing up your databases this time will not really decrease very much at all since your backup software is only backing up your usable data and since you will not decrease in the amount of usable data then you won't decrease your backup time. What versions of backup media and software are you using?
Lee W, MVPConnect With a Mentor Technology and Business Process AdvisorCommented:
Similar to what Mickeyfan said - I would split them up so that if the database became corrupt, you don't lose everything.  In addition - keep in mind, if you need to repair/defrag the database(s) the larger the files, the longer it takes for those tasks to complete.

As for additional disk space, I would suggest you think outside the box - look at DAS - Direct Attach Storage, or if you can gather the money, use a SAN - then, since you have at least one Enterprise license, you could cluster and increase your potential uptime.
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