100K Users OCS to Zimbra

[Hellschwarz]

Hi,

I hope you can give me some helping experiences.

A short Introduction of myself and the association I am working for.

This system is based on the Oracle Collaboration Suite and not supported anymore. The system is needed to secure that the recipient got the mail. I Knoow w'ell have to develop a special protocol for that. The architecture will be closed that means onyle mailboxes within our adressbook can communicate with each other.

That is the reason why we have to migrate nearly 100K mailboxes to a new system.

We have to decide until end of September between 3 System:

One of that is Zimbra.

I have to say that i have a lot of concers to migrate to an open source system. We thought about using the community version because we have to add a lot of funktionality to our groupware installation and we only have very low budget because our customers are not-for-profit sport clubs.

My questions to you..

Do you think that we can run a high available instance of Zimbra with 60K-200K mailboxes?

Which experiences have you made with administrating Zimbra?

How many days have we to calculate only for administrating a system like that?

How secure is it running Zimbra? Are eploits rapidly fixed by the comminty?

Sorry for my horrible English and thank you for your answers...

Sascha

[LMStone]

Hi Sascha,

Welcome to the forums!

There are a number of posters here in the forums running large Zimbra systems with more than 100K users.

For high-availability, Zimbra supports Red Hat Cluster. You can also use hardware duplicated (also called "fault tolerant") servers from Stratus or NEC, both of which are VMware certified. Our preference is to use fault-tolerant servers over RH Cluster because they require much less administration and maintenance over the long-term than a software-based cluster and, in our experience, provide higher uptimes.

VMware also have their own HA and DRS offerings, too, which I would encourage you to evaluate as well.

As regards security, there have been only a few exploit-related security patches Zimbra has released over the fours years in which we and our clients have been using Zimbra. The key open-source components within Zimbra have good security track records as well. An external Nessus scan against a Zimbra server for example won't show much in the way of problems at all.

Planning the architecture for 100K users however requires an evaluation of your mail volumes, the features you intend to use, the methods by which users will connect, and a number of other items to ensure you get the performance you need at a good price.

Hope that helps,
Mark

[Hellschwarz]

Hi Mark,

thank you for your answers. It helped to dsipel my doubts in the safety aspect.

I feel now more confident that Zimbra will be a same secure solution combined to other proprietary systems on the market.

We will evaluate those combination of clustering, you mentionend.

"Planning the architecture for 100K users however requires an evaluation of your mail volumes, the features you intend to use, the methods by which users will connect, and a number of other items to ensure you get the performance you need at a good price."


Thats really simple because of the closed communication community there is not so much functionality needed. The community can only communicate with each other. There is not possiblity to receive mails from outside the community.

- The users only have access through the webclient. No other access is allowed and will not be allowed in the future.

- The Users have the right to forward mails to their private Email outside the closed system.

- The volume of the post boxes is limited to 100 MB.

- One important aspect is that a sender can watch the status of a mail within the system. For Example... Sent... Received.... Read... Deleted...

That is necessary to secure the delivery... That functionality must be developed in all systems which were offered to us.

Now comes something interessant and I think something special for our system. Normally we have only a peak of 750 concurrent users. And 80% of all messages which will be sent through this mailsystem are generated by an outside standing application which has its own mailbox.

One thing which is allthough special, creating or deleting an account mus be possible from a selfdeveloped outstanding application.

I am not scared of any performance problems... The only important things are the interfaces between Zimbra and our existing administration system and Zimbra and all modules in our application landscape that sent mails through this technical mailbox user.

Best regards

Sascha

[LMStone]

Hi Sascha,

That's a very unique configuration. It is very unusual to have only 750 concurrent users when there are 100,000 mailboxes. Certainly 750 users with that small a daily mail volume could fit easily on just one server, but with 100,000 mailboxes, there are a number of other issues to consider, including inodes, MySQL tuning etc.

Zimbra's API and commandline scripts cover a lot of functionality, and are capable in principle of doing what you describe. Certainly the Zimbra scripts are more comprehensive than all of the Power Shell scripts for Exchange 2010.

I would recommend configuring a test system after familiarizing yourself with the following two documents:

Performance Tuning Guidelines for Large Deployments - Zimbra :: Wiki

Talk:Performance Tuning Guidelines for Large Deployments - Zimbra :: Wiki

Keep us posted as to the results of your testing!

Hope that helps,
Mark

[wesleylago]

I've worked with zimbra elsewhere and I'm happy with Zimbra, but I have a mission to migration oracle colaboration suite where I do not have much knowledge to zimbra.

Sorry for my horrible English and thank you for your answers...