Tag Archives | exchange

VMware Zimbra vs. Microsoft Exchange – Follow-up


I am truly excited by the response to my Zimba vs. Exchange post from a couple weeks back. I would like to thank my readers and especially those who commented for their valued feedback. The response thus far shows that there is definite interest in alternatives to Exchange for e-mail and collaboration needs at various industries and organization types.

I believe is important to be open to competing viewpoints as well, and it is this type of interaction that causes software organizations to sit up and take notice at what they are doing right or wrong and how they can improve to expand their offerings to a wider audience and to improve the customer experience.

That said, I would like to point you to a post here & here co-written by two obvious proponents of Exchange, by the names of Michel de Rooij and Dave Stork. They put forth a rebuttal that can serve as a response (albeit somewhat flawed) to my arguments in favor of Zimbra. The comments on my post, as well as those on their sites, should be reviewed as well, as they provide constructive feedback on the validity of our arguments on both sides of the fence.

I welcome this sort of feedback and look forward to continuing the conversation throughout the Zimbra product life-cycle as well as similar or competing offerings from VMware, Microsoft and their partners.

The fact that I got a response of this magnitude not only shows that there is significant interest in Zimbra, but also that Exchange proponents feel a need to defend their territory proves that Zimbra is on their radar. I think this bodes well for competition in a Microsoft-dominated world! “No publicity is bad publicity”, so they say…

Thanks for reading!

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VMware Zimbra vs. Microsoft Exchange



In this post I would like to propose the idea that VMware Zimbra Collaboration Server can serve as a drop-in replacement for Microsoft Exchange in Enterprise environments of all sizes. I would also propose that Zimbra is better suited for multi-tenant ISP deployments than Exchange. Let’s discuss the pros and cons of Zimbra and give you the background to consider Zimbra for your next e-mail deployment or customer engagement.


Technically, VMware Zimbra is part of VMware’s End-user Computing catalog, but I would also consider it as a good example of a Tier-1 application, once deployed. E-mail is becoming so critical to the operations of any size business that it needs to be designed, implemented and maintained with the same level of care as any other Tier-1 app.

Benefits Overview

That said, the ease with which backup and restore can be performed in Zimbra far outweighs the capabilities of Exchange. A good backup/restore strategy is one of the cornerstones of any Tier-1 app deployment worth its salt. Add to that the fact that Zimbra has orders of magnitude better scaling capabilities than Exchange, all at about 50% of the price, on average.

Storage Benefits

Combine Zimbra with NetApp storage platforms and technologies and you will see even more efficiences around the storage required for backup, attachments, etc. (using NetApp’s deduplication technology) in addition to ease of management. Snapshot technologies allow quick backups of e-mail and attachment data resulting in quick restoration when you run into issues. Cloning technologies (FlexClone) will allow you to reduce time required for upgrades by allowing staff to test upgrades with a live copy of recent production data. Replication technologies (SnapMirror) will allow you to move data backups to remote locations for disaster recovery or remote backup facilities for compliance purposes.

General Comparisons

Here are some other comparisons that can be drawn between the 2 platforms:

Key Features Exchange 2010 ZCS 7.x

Platform Architecture

Core architecture “Extensible Storage Engine (ESE)” is over 20 years old and is a non-modular .edb file which doesn’t separate message and metadata, so is not conducive to tuning. Database availability group (DAG) uses components with a DNA based on Windows failover clustering, but has yet to be proven for large deployments.

Modular architecture offers Web 2.0 features and cloud scalability. Message and metadata are separated to allow granular tuning and optimization flexibility.

Platform Reliability & Robustness

Microsoft is considering moving the storage engine to SQL Server.
Microsoft has yet to prove the robustness of the new architecture.
ZCS leverages a Linux-based operating environment for greater levels of robustness using proven open source components.
Uptime measured in years instead of weeks.

Platform Scalability

Exchange doesn’t support the use of tiered storage, so adding more users is more costly than in Zimbra.

ZCS supports storage tiers and can scale to millions of users at lower cost.

High Availability

DAG only provides mailbox protection, not protection for the Exchange infrastructure.
DAG has a learning curve and only applies to Exchange.

ZCS in conjunction with SRM is a proven, scalable and effective high availability solution.
Companies can leverage their existing HA/DR solution with ZCS.

Platform Extensibility

Recommendation is to use Microsoft’s proprietary shell. SOAP API has limited server access. Outlook add-ins require significant developer effort and are difficult to support.

SOAP API allows server access. Uses the web services framework for client access and Zimlets for integration with 3rd-party services.

Platform Openess

Microsoft is a closed ecosystem. Developers cannot change or extend platform or APIs.

Based on open source code and extensible using open source programming languages.

Support of Open Standard Protocols

Limited support for the SOAP protocol. No support for REST, CalDAV, CardDAV and ICS.

Support of open standard protocols such as SOAP, REST, CalDAV, CardDAV and ICS.


Outlook Web Access has only a single theme in Exchange 2010, so users cannot switch between themes.

Complete re-branding of the client is possible. Ajax web client has feature parity with the desktop client.

Web-client End-user Access

Limited browser support for OWA.

Rich Ajax/HTML web client is supported on a broad range of browsers and platforms.

Mac Desktop

Parity with Outlook.

Zimbra’s desktop client is supported with Mac OS X and has feature parity with the web client.

Linux Desktop & Server

No Outlook client for Linux. No Exchange server for Linux.

Zimbra desktop functions on Linux and has complete feature parity. ZCS server components love the Linux platform.

Mobile Support

Fully supports push using Microsoft’s ActiveSync technology.

Supports ActiveSync push for calendaring and e-mail.

vSamurai’s Take

Zimbra has been a passion of mine since I started using it back in 2006-2007. My previous company had evaluated implementing Exchange, Zimbra and a couple of other solutions. Due to our IT management and staff being huge proponents of Open Source, we decided on the Zimbra solution. I am very glad that we did. To be honest, despite the fact that we had users who were used to the Outlook client, we didn’t have much pushback when we moved to Zimbra as it has full feature parity with Exchange. I expect that your results may be the similar if Zimbra is given a serious look for new e-mail implementations or during hardware/software upgrade cycles in pre-existing implementations of Exchange.

Expect to hear more soon about the ins and outs of deploying Zimbra in your or your customer’s environment. SaaS is here and this is just one part of VMware’s End-user computing strategy, so look for more in the future from them as well.


Thanks go out to Jim Millard who had a good point on Twitter, which is that I forgot to compare ActiveSync capabilities between Exchange and Zimbra. Well, the good news is that Zimbra Network Edition fully supports ActiveSync capabilities for push of e-mail and calendar appointments.
I use it everyday, in fact, between a Zimbra e-mail account I have set-up in 01.com’s zMailCloud and my iPhone 4. You configure it just as you would an Exchange account on the iPhone (see here). I receive meeting requests that can easily be added to my calendar with automatic reminders as well. You can also deploy Zimbra to work with Blackberry Enterprise Server.

To be sure, these features are only available with the paid Network Edition of Zimbra, however, they are still much less costly than Exchange. Based on my experience, I believe the mobile functionality to at least match that of Exchange, however, I recommend that you look at doing a PoC and ultimately make that decision on your own as your results (as with everything) may vary.

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