opinions on architecture

[ShackDaddy]

I met someone last week who asked me what I thought of their proposed E2007 architecture, and I had mixed feelings so I thought I'd get some other opinions:

Environment is set up to serve 300-500 mailboxes.

Single quad processor server with 18gb of ram. Running Hyper-V Core on mirrored SATA drives.

Virtualized instance of E2007 Mbox/CAS/Hub server on W2008. 12gb of RAM allocated.
Virtualized instance of E2007 Edge on W2008. 4gb of RAM allocated.

The main point of virtualization here is to be fully portable, since they have another couple of ram-rich HyperV servers on hand. I still haven't seen anything solid from Microsoft on how to approach virtualized mailbox servers, so let me know if there is something out now.

The .vm files for both virtual servers are actually on a backend SAN.

I don't work enough with SANs to know whether that's a good idea or not. Is it?

What do you guys think?

Dave Shackelford
Shackelford Consulting

 

[58sniper]

There isn't enough for me to say for storage, but I'm no fan of SATA for anything other than archiving. They're just too slow, especially when it comes to transaction log performance. If they're planning on doing mirrored SATA drives to hold everything, they're in for some pain.

Hyper-V complicates things a little, but the Microsoft direction is away from SAN and towards DAS.

There certainly isn't any redundancy in this scenario other than what's in Hyper-V.

Pat Richard MVP

 

[ShackDaddy]

The SATA is just supporting the OS/pagefile, that's all. Everything else, including the Exchange app dir, the logs and the mail databases, is going to be on the SAN.

I have no experience with SANs. Are they going to get better throughput from a SAN than from SATA?

This setup would be at a hosting company, so they'd be using a SAN that the provider has there.

Dave Shackelford
Shackelford Consulting

 

[58sniper]

If the SAN is using SAS drives, the performance would likely be better.

Pat Richard MVP

Plan for performance, and capacity takes care of itself. Plan for capacity, and suffer poor performance.

 

[Zelandakh]

If it is a proper SAN then it will be fibre based so the performance will be great especially as large amounts will be in RAM on the host. This should fly if properly configured. Obviously depends on user throughput - 300 light users won't tax it, 300 super heavy users may cause it a head ache but you won't know that until you stress test it.

 

[SilviaS]

I have never used virtualised .vm servers for exchange, how does the performance vs a standard server build with SAN iscsi backed perform?

 

[xmsre]

I think I'd stick with SCSI or SAS for the OS/Pagefile. Exchange 2007 pages quite a bit, and there are know issues with wokingset trimming/paging during cold start (the stime from boot or service restart until the cache is populated) that can lead to unresponsiveness.

 

[Zelandakh]

You can't compare performance os physical vs virtual without comparing actual specs, RAM, IOPS etc.

 

[Zelandakh]

I thought Exchange paged a good deal less than 2003?

 

[NJForensics]

I have setup a ESX 3.5 environment with two physical hosts. One running a single server 07 deployment, with 12 GB, 2 Quad Cores. It was setup on an EMC AX4 with hot failover to a standby ESX server.

Overall, you will really see performance drops if you go under 12GB in a virtual environment. Bear in mind, this was based on just a 100 users.

The disk performance was fantastic, and that was just with 10K SAS drives via iSCSI. I would imagine significant improvement with 15k ones.

Overall, get a beefy enough server and 07 will fly.

Chris Clancy, EnCE CCE

MCITP: Enterprise Messaging
MCTS: Active Directory 2008

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