owblueiii
Contributor
Contributor

Exchange Install/iSCSI Config.

Hello, I have been doing some research and am at a loss at the moment. I have my HP G7 server (RAID 1 146GB drives) configured as a host. I have created an LUN to connect to my iSCSI SAN and I'm not trying to figure out the best way to install Exchange. Currently, I created a 250GB LUN to the SAN. From what I have been reading, Microsoft prefers the database and logs to reside on different physical media. Does this mean I cannot have my virtual server and Exchange all installed on the SAN? Should I install the OS and Exchange locally on the HP server and then withing the virtual server create LUNs for the database and logfiles on the SAN? I'm really looking for some guidance here on the configuration. I'm only going to be hosting 200 mailboxes. Thanks in adance for any assistance.

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JRink
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I manage 3 different Exchange 2007 servers in different VM environments (from 100 mailboxes up to 700 mailboxes). In ALL 3 configurations, I am using the same datastore (disk array) for my OS, log files, and Exchange DB. I have seen ZERO problems doing this.

It's my personal opinion (YMMV) that if you're running Exchange in a smaller environment like you seem to be, that running your OS, logs, and DB from the same disk array and datastore is more than fine and you will suffer no performance hits - assuming your datastore is not heavily taxed for IO from other VMs.

Of course, this ALL depends on YOUR environment. There may be times where a small exchange server is so heavily utilized and transactional logs could benefit from a seperate array (as per MS recommendation) but I've yet to encounter the need.

EDIT - 2 of the Exchange servers (the 2 larger ones I manage, 500 mailboxes and 700 mailboxes respectively) are running over iSCSI, while the smaller Exchange server (100 mailboxes) is running over local datastore.

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owblueiii
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Contributor

Thanks for the info. One option I was considering was to assign 1 LUN to the VMware host and then once I have Windows 2008R2 installed, was to setup initiators inside the OS that the Exchange database and Log files could reside on? Have you heard or seen any issues with this configuration? Also, any recommendations on partition sizes? Would 2 processors and 8GB of memory be enough to support this setup. I am only planning on running one other VM on this server and that would be a BES.

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JRink
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I guess I wouldn't bother setting up iSCSI within the VM itself, so long as you have a valid iSCSI storage network setup between the SAN and ESX itself. I have never bothered to try the option you mention... Seems like extra complication that isn't needed if iSCSI is already setup between the SAN and ESX. (?)

2 procs and 8GB should be more than sufficient. Each of my 3 Exch 2007 VMs only have a single vCPU applied (though 1 of the VMs could probably use an extra vCPU since it's also running Microsoft EBS). I typically assigned 4GB of memory to the VM and monitor accordingly.

I would imagine you should be perfectly fine if your Exchange users are typical Exchange users...

(Also, for reference, my Exchange datastores are from 40GB to 80GB in size... We typically put fairly restrictive mailbox storage limits on each user's mailbox to keep the mailbox store size manageable. If you're information store is WAY bigger than the ones I manage, you may want to ask input from another Exchange admin to size accordingly for performance).

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owblueiii
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Contributor

JRink, thanks for the helpful information. I'm going to continue to do some research before making a final decision. I had post on the Microsoft Forums, and someone had mention creating a separate vhd for the logs and data files. They stated that this could be found in the settings of the configured virtual server. So, I might look into that scenario.

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JRink
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If they're talking VHD files, then I think they're referring to MS virtualization, not ESX. but regardless....

If the logs and data files are on the SAME physical disks (array), it really doesn't matter whether they're located on a different Logical drive (of VHD) or not (other than organizational purposes), you're not going to gain any performance going that route. I think you'll be MORE than fine running your logs/data on the same physical disks (read:disk array and LUN) as your OS - based on my experiences. I would probably only consider making sure my data/logs were on seperate physical disks (read: disk array and LUN) in a LARGE Exchange organization. 200 mailboxes though? I wouldn't bother...

But again, it's possible your 200 mailbox organization could tax Exchange wayyyy more than an organization with 1000 mailboxes... All depends HOW exchange is used and how much acitivty is going on, size of the Information Store, etc.

Just my opinions, others may disagree.

Regards

JR

owblueiii
Contributor
Contributor

Again JRink, thanks for all your helpful information. Greatly appreciated.

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pie8ter
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Contributor

JRink,

How did you come to the conclusion that your exchange servers are working fine? Did you ask the users and came to conclusion? or Did you gather data from the counters for IOPs, latency, disk bottlenecks, etc and came to the conclusion? If you used counters to reach your conclusion, I would like to know the stats for the server with the 700 mailboxs.

Thanks

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