number of IOPS needed for Domain Controller for 500 users

[dutch_guy]

Hi, i'm looking for some average numbers of required IOPS for standard domain controller operations. Suppose 500 users are in a single forest/domain.

How many IOPS would the Active Directory use? Somebody have some links to point me in some directions?

thanks in advance!!!

[rickardnobel]

That would also depend on how many Domain Controllers you have, since the load will be distributed amongst them.

However, in general does AD not require much IO. A single user is something like 8 KB in the database and is typically cached into the DC:s RAM until next logon. There there is some GPO:s that should be read from the SYSVOL folder and sent to the client, but these are also typically very small in size.

[Josh26]

I would put it this way:

Nearly everything else you can do with 500 users, including file shares and even print servers, will be more relevant to your IOPS than a Domain Controller.

I'm sure you're to want multiple of these by the way.

[suhag79]

May be useful link on Calculating IOPs,

http://www.vclouds.nl/2012/04/25/calculate-iops/

[rickardnobel]

Suhag Desai wrote:

May be useful link on Calculating IOPs,

http://www.vclouds.nl/2012/04/25/calculate-iops/

That is a good description of how to calculate the amount of random IOPS on different kind of disks and RAID levels. However, in this case I think the original poster knows what the physical disks can deliver and is now designing how many VMs could be put on top of those disk arrays.

[Paul11]

Our Domain Controller is only doing about 6 IOPS in a Domain with 1000 users. You can see the graph with 125 IO's in a 20 seconds intervall, so you had to devide the Summation Number value by 20.

[rickardnobel]

It is interesting to see that your IOPS does not ever raise around 8 (assuming your users start their work day around that time.) This is most likely because Active Directory caches most of this information in RAM after the first read, which makes the IO need very low. The AD process (lsass.exe) could grow some in memory over time and it could be good to verify that that fits into RAM good.