EMC SAN and Drive letters

You would probably be fine with keeping all of the stores/logs for 1 storage group on 1 LUN.

So if you have 30 Stores, it would be 6 Data LUNs and 6 log LUNS.  Then again seeing that you purchased 300 gig drives, that isn't the most efficient way to plan for exchange.  Exchange should be planned with IOPS as the primary priorityand storage capacity as the second priority.

I would say make a RAID 5 Raid Group (5 disk) for each Storage group you have.  Make 1 LUN for each, and put all the stores for that storage group on that LUN.  So if you had 6 Storage Groups, you would need 30 spindles for data.

For logs, you need to keep them separate from your data.  Data is random I/O and logs are sequential I/O.  You want to try to keep random and sequential on separate physical spindles.  For logs you could make a 2-4 disk RAID-10 (or RAID-1) raid group and carve a LUN for each Storage group.

I would recommend using smaller disks (146 or 72 gig) and not putting anything else on them except exchange until you gauge the performance using NaviSphere Analyzer.  And only put 1 storage group on a RAID group.  Don't try to double up.

FYI... How many users do you have and how big is the total of all your stores?

Also, the 64kb offset will save you a lot of headaches in the long run.  RAID-5 random writes uncur a 4 I/O (2 writes, 2 reads) penalty for every 1 write.  If you don't do the 64kb offset, you will double your penalty to 8 for some of your writes.  Not doing the offset will strip about 20% of your performance away.  You cannot do this once a LUN had been initialized in the OS.  You need to do this before you format and out data on it.  If you haven't done this, I suggest you make a new LUN, set the alignment and then move the stores over during a maintenance window.

Exchange is one of those things you have to get right the first time, or it can lead to a lot of problems later.

To make the drives usable, just go into computer manager --> storage --> disk management and initialize the LUNs you added to your exchange server's Storage Group (EMC CLARiiON storage group, not exchange)

AnthonyP9618: - thanks for the article on mount points.

It's still not clear to me how this is accomplished in my situation. I am trying to create the mount point on our SAN so it's always available even if one of the servers goes down.

So basically i have this:
On the san i create a small 1GB lun that will hold the mount points.
I then go to one of the servers and use diskpart to set the offset to 64
I then use disk management to format the drive.

The next step is where im a bit fuzzy.
Do i create a drive letter at this point? or do i  select "Mount in the following empty NTFS folder"
The latter doesn;t seem to work properly, and if i assign it a drive letter the other servers can;t see the drive letter..

What am i missing?

Can the other servers even see the drive?

On the CLARiiON, do you you have a storage group with all the hosts in the cluster added to it?