When do I need another Exchange Server
Hi Guys,
I look after several clients with on premise Exchange Servers. Most clients are relatively small but I have one that has grown quite considerably in the last 12 months and they now have 150 mailboxes on a single Exchange Server. The mailboxes have a combined size of 250GB and are spread over 5 databases.
Its a Exchange 2013 (SP1) Server and is running virtually (HyperV). The Physical host is a Dell Powerdge R710 with 6x 600GB 15k SAS disks in RAID 5.
The Exchange VM has 16GB of RAM and 8 CPU's allocated to it. The databases are stored physically on the RAID 5 disk set using two different virtual disks.
The issue Im having is the client is reporting Exchange Freezing a random times during the day. The Exchange Server was originally pretty quick but has slowed down as more users have been added to it. The client reports the freezing occurs multiple times every hours and lasts for 10secs+ each time.
My question is this - given the above setup, how many users should I be expecting to run comfortably off this Exchange 2013 Server?
At what point typically would you consider adding another Exchange Server? I haven't tried any performance tweaks (other than sprading the load overe several databases), its a stock install. I know its good to have a second Exchange Server for redundancy (so I will be probably adding a second one anyway) - but based purely on performance considerations, is there a magic number of mailboxes you can typically get working off a single Exchange 2013 Server?
I tried to use the Excel calculators provided by MS, but they seem to be suited more towards companies with bigger user bases.
The client is also not interested in Office 365 because they want to keep all their data in house.
I look after several clients with on premise Exchange Servers. Most clients are relatively small but I have one that has grown quite considerably in the last 12 months and they now have 150 mailboxes on a single Exchange Server. The mailboxes have a combined size of 250GB and are spread over 5 databases.
Its a Exchange 2013 (SP1) Server and is running virtually (HyperV). The Physical host is a Dell Powerdge R710 with 6x 600GB 15k SAS disks in RAID 5.
The Exchange VM has 16GB of RAM and 8 CPU's allocated to it. The databases are stored physically on the RAID 5 disk set using two different virtual disks.
The issue Im having is the client is reporting Exchange Freezing a random times during the day. The Exchange Server was originally pretty quick but has slowed down as more users have been added to it. The client reports the freezing occurs multiple times every hours and lasts for 10secs+ each time.
My question is this - given the above setup, how many users should I be expecting to run comfortably off this Exchange 2013 Server?
At what point typically would you consider adding another Exchange Server? I haven't tried any performance tweaks (other than sprading the load overe several databases), its a stock install. I know its good to have a second Exchange Server for redundancy (so I will be probably adding a second one anyway) - but based purely on performance considerations, is there a magic number of mailboxes you can typically get working off a single Exchange 2013 Server?
I tried to use the Excel calculators provided by MS, but they seem to be suited more towards companies with bigger user bases.
The client is also not interested in Office 365 because they want to keep all their data in house.
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Your one server should be fine for the user base you have. I agree with the above statement about switching to cached mode. It will reduce quite a bit of load on the server. Every time a user does a search of their mailbox in Online mode it puts a hurt on the Exchange server. If enough people are searching all once then you could have performance issues like you are experiencing. In cached mode the local Outlook client does the indexing and it just synchronizes the email which is much less demanding on the server.
You can turn caching on through a GPO if you want. Just be careful when you do, if all the users log in at the same time after you enable it then they will all be downloading all their mail at the same time which could be quite slow. You could filter the GPO to a group of users and slowly add groups of people until they are all done.
I am not sure what you are doing for backups on the Exchange server but I have seen some DPM implementations and other third party backup solutions that run quite frequently and those too could be hurting your server performance during the day when it is being used. You may want to double check your maintenance schedule.
Other than that, adding a second server COULD help your load if you had the physical resources to add a second virtual Exchange. If you have the spare resources though you can try and just bump up Exchange and see if that helps.
You can turn caching on through a GPO if you want. Just be careful when you do, if all the users log in at the same time after you enable it then they will all be downloading all their mail at the same time which could be quite slow. You could filter the GPO to a group of users and slowly add groups of people until they are all done.
I am not sure what you are doing for backups on the Exchange server but I have seen some DPM implementations and other third party backup solutions that run quite frequently and those too could be hurting your server performance during the day when it is being used. You may want to double check your maintenance schedule.
Other than that, adding a second server COULD help your load if you had the physical resources to add a second virtual Exchange. If you have the spare resources though you can try and just bump up Exchange and see if that helps.
Not sure why the users would not be using cached mode as it is enabled by default.
Will.
Will.
It isn't the user count, or database size that tells you when you bust out. It depends on how the users are using the system. What is average cpu, memory, disk, and network utilization? Find the bottleneck. I'll tell you one thing, doing RAID5 is HORRIBLE for exchange. You might need nothing more than to add a pair of 15K RPM drives, configure as a RAID1, and move the O/S, swap, and scratch table space there. If you're disk I/O bound this could very well give you a 2-5X improvement in overall system performance.
Note the 2 disks must be dedicated to the exchange VM, not shared among everything. VMWARE is not efficient at disk I/O.
Note the 2 disks must be dedicated to the exchange VM, not shared among everything. VMWARE is not efficient at disk I/O.
ASKER
We are running Exchange 2013 Standard and the databases range from 20 to 90GB, they are split along logical organisational lines.
So if we are having performance issues, can you point me towards some literature which will help be debug why the server isn't performing well?
From what you are telling me, I assume a single Exchange 2013 Server should have no problem with running many more mailboxes than what this client currently has and if there is slowness I should be looking for hardware bottleneck?
So if we are having performance issues, can you point me towards some literature which will help be debug why the server isn't performing well?
From what you are telling me, I assume a single Exchange 2013 Server should have no problem with running many more mailboxes than what this client currently has and if there is slowness I should be looking for hardware bottleneck?
ASKER
The reason why Cached isnt turned on by default is because most of the users access Exchange via Remote Desktop Services. I might just have to add another volume to these RDS Servers and dump the OST files there ...
Just regarding the comment about RAID 5 not being good for Exchange, are there any best practice guides you can point me towards?
I am about to deploy a Dell MD3860' SAN for this client, so I will be able to reconfigure the disks how I like. Which RAID set do you recommend I configure for the Exchange OS Partition and which RAID Set should configure for the Data?
Just regarding the comment about RAID 5 not being good for Exchange, are there any best practice guides you can point me towards?
I am about to deploy a Dell MD3860' SAN for this client, so I will be able to reconfigure the disks how I like. Which RAID set do you recommend I configure for the Exchange OS Partition and which RAID Set should configure for the Data?
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
By remote do you mean remote desktop? ie they dial into their work desktop machine?
Or via VPN?
Either way cached would still be better for the user
Or via VPN?
Either way cached would still be better for the user
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
These other guys are much better with Exchange than myself but i would suggest starting with cache mode just because its the easiest to do and requires no investment or updating of systems. See if you get any improvement and then move on from there with the other experts suggestions if needed
Good luck ^_^
Good luck ^_^
ASKER
thanks.
If that is true then you do have a considerable amount of growth available. Theoretically you can have up to 16TB database, but this is not practical when it comes to backup and maintenance but having a 400-500GB database is completely acceptable.
Also if you plan to incorporate another Exchange Server this will be added licenses so I would leverage both DAG members 2/3 split so that you can get use out of both mailbox database servers. Also load balancing CAS as well with a hardware load balancer is preferred.
Check out performance sizing
Performance Sizing Cheat Sheet
Sizing Deployments
Will.