Hardware Requirements

[uberdol]

Hello,
I am relatively new in here, and apologies if this question has been asked before. Our company would like to move forward installing Zimbra on production. We've been testing Zimbra and I think It will fit well in our organization.
What we would like to do is to install Zimbra into two separate VM's. So we have the following questions:
Based on your experiences, for 50 Users and 1GB of email quota each:
1) How big the disk size should be for each VM?

2) How many virtual CPU's we should allocate for each VM?

3) How much memory should we dedicate for each VM?

4) Can we Install Sun LDAP (Sun Directory Server 7.0) instead of OpenLDAP. Is there any LDAP specific installation documentation for zimbra I can look at?
I appreciate all the feedback and I look forward to seeing your answers.
Regards,

Deniz.

[phoenix]

[quote user="uberdol"]What we would like to do is to install Zimbra into two separate VM's.[/QUOTE]Why would you want to do that for 50 users?
[quote user="uberdol"]Based on your experiences, for 50 Users and 1GB of email quota each:
1) How big the disk size should be for each VM?

2) How many virtual CPU's we should allocate for each VM?

3) How much memory should we dedicate for each VM?[/QUOTE]The answer would depend on the profile of usage for the users, are they going to be using IMAP/POP3/Web UI, how many of them will be online at once, what levels of mail will you be getting? You can also never have too much HD space and on a RAID10 as well. Which VM hypervisor are you using? What else is running on this server? What are the specifications of the hardware (including HD subsystems)?


[quote user="uberdol"]4) Can we Install Sun LDAP (Sun Directory Server 7.0) instead of OpenLDAP. Is there any LDAP specific installation documentation for zimbra I can look at?[/QUOTE]If you mean in place of the Zimbra openLDAP then the answer is no, LDAP is tightly integrated into Zimbra and can't be replaced. If you mean as an additional LDAP server for external authentication then the answer is yes, it can be used for that. I would, however, suggest that for performance and scalability you should use a recent build of openLDAP rather than the Sun offering.

[uberdol]

Hi Bill,
Thank you very much for answering me quickly.
Are 50 users too big for two VM's? What do you recommend? We'll be growing, and use VM's failover/backup...
I would think mostly users will be using clients like Thunderbird with IMAP. Some will be using Web GUI, it is hard to say at this point. I can't say exactly how many users will be online at the same time. I am assuming you're referring to WEB UI when you say 'online'.
We're using vSphere 4 and currently we have 2 ESX Sun Fire X4170 servers running. There are bunch of test/dev vms, about 5-10 and not online all the time. We have about 7 production vm's running. We have enough space on the SAN.



So given the fact that we have two ESX servers with good enough space:

1) How big the disk size should be for each VM?

2) How many virtual CPU's we should allocate for each VM?

3) How much memory should we dedicate for each VM?
We've been using Sun Directory Server's quite happily actually, but if you say that it can't be replaced with Zimbra openLDAP then we'll have to use our DS as an additional LDAP server.
Regards,
Deniz.

[phoenix]

[quote user="uberdol"]We've been using Sun Directory Server's quite happily actually, but if you say that it can't be replaced with Zimbra openLDAP then we'll have to use our DS as an additional LDAP server.[/QUOTE]Sorry, I may have misunderstood your earlier question. Do you want to replace your SDS by using the Zimbra openLDAP for authentication in your domain (i.e. use Zimbra as a Domain Controller)?

[uberdol]

Sorry I meant that we've been using Sun Directory Server for other purposes than zimbra quite happily. We wanted to see if we could integrate our Directory Server with Zimbra.
It is my understanding that zimbra can talk to external DS'es but Zimbra openLDAP has to be installed in the zimbra server. We can not replace zimbra's ldap with our DS in the installation process or after installation, correct? So if zimbra can talk to external DS, then why do we need to use zimbra's own ldap? can't we just bypass it?
Could you also comment on my other questions if you have some estimates?

Thank you so much.
Deniz.

[L. Mark Stone]

[quote user="uberdol"]Hi Bill,
Thank you very much for answering me quickly.
Are 50 users too big for two VM's? What do you recommend? We'll be growing, and use VM's failover/backup...
I would think mostly users will be using clients like Thunderbird with IMAP. Some will be using Web GUI, it is hard to say at this point. I can't say exactly how many users will be online at the same time. I am assuming you're referring to WEB UI when you say 'online'.
We're using vSphere 4 and currently we have 2 ESX Sun Fire X4170 servers running. There are bunch of test/dev vms, about 5-10 and not online all the time. We have about 7 production vm's running. We have enough space on the SAN.



So given the fact that we have two ESX servers with good enough space:

1) How big the disk size should be for each VM?

2) How many virtual CPU's we should allocate for each VM?

3) How much memory should we dedicate for each VM?
We've been using Sun Directory Server's quite happily actually, but if you say that it can't be replaced with Zimbra openLDAP then we'll have to use our DS as an additional LDAP server.
Regards,
Deniz.[/QUOTE]
Even 50 very active users still needs no more than a single server. We see a number of single-server Zimbra installs carrying 600 or more power users with no noticeable loss in performance.
If you were very concerned about maximizing and maintaining absolutely top performance for the end users and/or your all of your users each send/receive several hundred emails per day; or if you expect to increase the number of users, then I might consider using a second server for MTA/LDAP replica-only and the first server for mailbox/LDAP master. But still, that's a "nice-to-have", not a "must-have".
On a 64-bit single server for 50-500 users, personally, I'd like to see 12GB of RAM. Anything more is overkill, and you could get by with half that easily for 50 users.
Re disks, fast 15K RAID10 is your best friend (along with a RAM disk for amavis's tmp directory). Zimbra, like most groupware systems, is very disk intensive. This is not the place to compromise on cost nor performance! As for sizing, that depends on how you set your quotas and how long you need to retain backups.
If you were going to limit mailboxes to 4GB each, for 50 users a pair of fast SAS 300GB disks in a RAID1 for /opt would give you growing room, especially if you added a pair of slower 500GB RAID1 SATA disks for /opt/zimbra/backup.
Hope that helps,

Mark

[uberdol]

[quote user="LMStone"]
On a 64-bit single server for 50-500 users, personally, I'd like to see 12GB of RAM. Anything more is overkill, and you could get by with half that easily for 50 users.
[/QUOTE]
Ok, Great! We could probably get by with 4-6GB then?
[quote user="LMStone"]

As for sizing, that depends on how you set your quotas and how long you need to retain backups.

[/QUOTE]
We are planning 1GB quota's for each user, not sure about backup process yet, though? Based on your experience what kind of backup retain policies on the average do you see? I am assuming we talk about backups of emails right?
[quote user="LMStone"]

If you were going to limit mailboxes to 4GB each, for 50 users a pair of fast SAS 300GB disks in a RAID1 for /opt would give you growing room, especially if you added a pair of slower 500GB RAID1 SATA disks for /opt/zimbra/backup.

[/QUOTE]
So you think 160GB Disks for 1GB would be OK or should we reduce the disk size a bit more since we're planning almost 1/4th of 4GB.
Thank you so much Mark....

[L. Mark Stone]

I wouldn't go less than 6GB RAM.
Disk capacity sizing is always tricky... Zimbra's default is to retain backups for 30 days. We have some clients who retain backups for a year. How frequently does each user's mailstore change? IOW, if you have 1GB quota, that's fine, but you cannot tell from that what the "churn" or "turnover" of a user's message "inventory" is.
One user may get 10 new short emails a day and be near quota all the time. Thirty days of backups for that user might be 1.5GB.
Another user might have only 500MB in their mailbox, but they might send/receive ten different 8MB PowerPoint presentations each day. Their backup space could be 3GB or more.
Bottom Line: Disks and RAM prices have come down so much over the past few years, that adding some extra capacity at the outset -- when compared to the costs of downtime to the company to add extra resources later -- is often by far the least cost solution.
Hope that helps!

Mark

[uberdol]

[quote user="LMStone"]I wouldn't go less than 6GB RAM.
Disk capacity sizing is always tricky... Zimbra's default is to retain backups for 30 days. We have some clients who retain backups for a year. How frequently does each user's mailstore change? [/QUOTE]
I did not realize that Zimbra kept 30 days backups. Our regular mailstore is 56GB and it is being backed up by Netbackup in incrementals nightly and full backups every two-three weeks I believe. All these backups are going to a different system or raid group.
And any suggestions for CPU allocation? Also, are you aware of any tools out there that does any capacity planning/sizing for zimbra?
Thank you so much for your answers.

[L. Mark Stone]

To be clear, it's the Network Edition which includes backups. If you go with the FOSS edition, there are a number of threads here on these forums with third-party backups scripts. You can always shutdown zimbra and just copy the whole /opt/zimbra tree -- just in case!
As regards CPUs, a single mid-speed quad-core would be more than enough. If you can afford a model with more L2/L3 cache, that will in our experience improve performance under load better than just a higher clock speed.
You could do this on a single HP DL-360 G7 1U server with no problem, even going so far as to install ESXi (via USB stick) as the "base" OS and then run Zimbra in a VM.
FWIW, we are SuSE Enterprise Server fans (there is nothing comparable to YaST and all the SuSEconfig scripts...) and it's cheaper than RHEL. And while there are plenty of folks here running Zimbra quite successfully on CentOS, it's not an "officially" supported distro. IMHO, I'd stick to a "supported" OS, especially if you will get the Network Edition.
Not trying to start a distro flame war here BTW, either!
Keep us posted as to your progress and of course feel free to post back as you spec out your server and prepare for the deployment!
All the best,

Mark