Exchange Configuration

[superco7]

We currently have Exchange 2k3 installed on a HP Proliant ML350G3 server running Windows 2k3, which only has 1 logical volume (2 hard drives in a raid 1 config). My problem is that Exchange is installed on the same volume as the OS. The server has room for a total of six drives (4 free), and has a HP Smart Array 641 Dual Channel raid contorller in it. Would my best bet be purchasing the additional 4 drives and put them in a raid 5 config and move the exchange logs and database over to this logical volume? If so does anyone have any good articles on how to do this? It looks as though it is as easy as copying the edb and stm files to the new drive and going into ESM and pointing it to the new location. Any help would be greatly appreciated.

Thanks.

 

[Zelandakh]

No...

Stick the 4 drives in. Configure them as a pair of mirrors. Get them formatted and visible in Explorer.
Then go to ESM. Change the location of the EDB and STM to the first new volume. As you hit reply, Exchange moves the files for you. You don't do it in Explorer. Then go to the logs, change the location to the other mirror/volume and again ESM will move the logs.

Full redundancy and lots of spindles to improve IOPS.

 

[superco7]

Sounds pretty easy. Thanks for the help.

 

[xmsre]

4 drives and put them in a raid 5 config "

Absolutely not. Use RAID 10.

Assuming 4 10K RPM SCSI spindles:

RAID 5 write performance = 64 IOPS
RAID 10 write performance = 170 IOPS

RAID 5 read performance = 255 IOPS
RAID 10 read performance = 340 IOPS

Mixed performance assuming a 2:1 read/write ratio:

RAID 5 = 191 IOPS
RAID 10 = 282 IOPS

Roughly 50% better overall performance for RAID 10 with an average Exchange DB workload. With the sizes of today's drives, there's no place for RAID 5 in an Exchange environment.

 

[blakey2]

To question the answers:

Using RAID 10 you end up with one 'logical drive' which is a striped array consisting of two discs, which in turn are mirrored. This means that the info store and logs would be on the same logical disc.

Using raid 1, you end up with two logical discs, which are not striped, but you can seperate the info store and log files onto seperate disks.

Which one is better performance wise for exchange?

From what I have read disk I/O for the information store is particularly random, whereas the log files are more or less contiguous?

Just curious as I actually have six SATA (7200rpm) 160GB disks set up in RAID 10 for an impending exch2k3 installation. This 'logical' drive is for the info. store and logfiles.
Would this configuration alter your reccomendations to that of the four disks??

CHEERS!

 

[zbnet]

I'd almost never combine the info stores on the same volume as the logs - for precisesly the reason you give, that the dbs are random access (and a mix of reads and writes), whereas the logs are sequential write (under normal operating conditions).

A pair of disks in a mirror is fine for the logs, especially of the capacity of the drives used is adequate to store a number of days' worth of logfiles (for when your backup fails and it takes you a week to repair it).

A mirror pair is usually okay for the dbs as well - although add additional stripe pairs in the RAID 10 if you want more capacity/performance. RAID5 had really had its day in modern Exchange servers.

So in essence, I support Zel's suggestion.

 

[Zelandakh]

Thank you kind Sir.

My main corp site runs RAID5 and it goes well - though there are a good number of disks in the set and they are fibre to provide speed, uptime and performance. RAID5 is a good way of utilising disks quite well and properly thought out can provide decent performance.

 

[58sniper]

When possible, always put the logs on mirrored drives. The performance is much more noticeable when they are mirrored vs. striped. My normal config:

OS: 2 mirrored drives
Paging: 2 mirrored drives
Exchange core files: 3 RAID5 drives, or appr. RAID10 if customer agrees
Exchange log files: 2 mirrored drives

Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)

 

[superco7]

Thanks for all of the input. Since I am limited to 6 drives on this server, it seems like my best option is to create 3 mirrors (one for OS, one for the log files and one for the databases). At least until I can get the separate drive cage and raid controller for the server. Thanks again.

 

[Zelandakh]

Ah - good plan. Pity no-one suggested that sooner.

(oh. yes they did. It was me)

 

[superco7]

Sorry about that Zelandakh, I was just agreeing that your idea seemed like the best option for my setup. I had no intentions of making it sound like it was my idea, I should have given credit where credit was due. Thanks for all the help. Have a good one.

 

[Zelandakh]