Monthly Archives: May 2009

6 Tips for a Smooth Zimbra Server Install

It may sound odd offering more Zimbra installation advice since there is a lot on the subject in other blogs, our documents, wiki and Forums. In fact, some quick research surfaced over 1.4 million hits for Zimbra server install on the web and 36,000 on the Zimbra site alone.

But we are also fortunate to have more new Zimbra users than ever, and after helping some trial customers recently, it was a good reminder a few simple tips can help cut through some noise and avoid time-consuming snags once you start the install process. So without further ado here are the top 6 common pre-requisites to consider when preparing for your Zimbra installation:

1. Firewall
Servers have firewalls configured once the operating systems are installed for security purposes. Our recommendation is to temporarily disable the firewall on the system during a single and multi-server Zimbra installation. An alternative would be to refer to our installation guide to get a list of ports (see Table 1) used by the application and make sure the ports are open prior to installation. Zimbra-ports

2. DNS setup
All Zimbra configurations store hostnames. We do not have save any IP address information in our configuration. The advantage is this allows an administrator to change IP address (more likely) on the Zimbra system without having to perform any application changes.

This scenario means that all the hostnames to be used in a Zimbra installation have to be defined in DNS. Both A and Mx records for the hostnames and email domains need to be defined and verified prior to beginning your installation.

One other thing to consider is split DNS configuration if you are dealing with servers separated by a firewall.

3. Use of Fully Qualified Hostnames (FQDN)
It is crucial to use a Fully Qualified hostname during the Zimbra configuration. For example, you should enter instead of server1. This avoids incorrect DNS address lookups and ensures that the client would be connecting to the right application.

4. Port Conflicts
Standard server configuration comes with support for numerous services like POP, IMAP and HTTP (see Table 1). These services are also installed with the Zimbra Network Edition. Therefore, you want to make sure you disable all these services prior to installation. The Zimbra installation scripts will check for any of these port conflicts and notify you to turn these services off before continuing.

5. Libraries and additional packages
Zimbra’s rich feature sets are dependent on additional packages being installed on the system. These packages vary between Linux and Mac Operating system. The Zimbra installation script does perform checks to verify all the dependencies have been met, but going through the System Requirements documentation (available on the Zimbra website) before will save you some time.

(Based on ‘Mailbox Usage of 200 MB’ and 500 users)

+ User Data: 500 users with 200 MB = 100 GB user data
+ MySQL data: 5% of 100 GB (User Data): 5 GB
+ Zimbra binaries: 10 GB
+ Zimbra logs: 20 GB
+ Zimbra indexes: 25% of 100GB (User Data) = 25 GB

100 + 5 + 10 + 20 + 25 = 160 GB
Backups: 160 % of Subtotal: 160 * 160% = 256 GB for backups
TOTAL: 160 + 256 = 416 GB

6. Sizing
Storage sizing is important for an excellent performing Zimbra application (see example). If you are doing a Network Edition trial you should contact the Zimbra technical team for sizing information for storage including number of disks, which Raid level to use, and the size of the drives to use. Configuration of the Zimbra store volume is important in satisfying the application IO requirements.

Remember, it’s also a good idea to review the Zimbra Quick Installation Guide where you can find this information and many more good tips.

Do you have a good tip to share? Feel free to add a comment!

Anup Patwardhan is the lead Zimbra sales engineer

The Ext4 file system: A real improvement in Linux file storage?

Since December 2008, the Ext4 file system is in the Linux kernel and is fully supported by all major Linux distributions. In this article you’ll find out if it’s time to make your migration plans, or if you should wait a while.

The Ext4 file system is backward compatible to the Ext3 file system, which is backward compatible to the Ext2 file system, which was invented in the early 1990s. Remember how big a big hard drive was in those days? Exactly, about 40 MB (yes, megabytes, not gigabytes) was considered huge at those days. Hence, the Ext2 file system was never developed with the multi-terabyte volumes that people tend to create now. That also means that the default maximum file and volume sizes in Ext2 and also in Ext3 are limited. If the default block size of 4 KB is used, a file with a maximal size of 2 TB can be created, and the maximal size for a volume or partition is 8 TB. Given the storage needs that companies have nowadays, this imposes a serious limitation.

When starting the development of Ext4, initially there were two directions in the project team. The first was to develop Ext4 as a fork of Ext3, making it completely compatible with this file system. The other option was to develop a completely new file system with support for new features, such as b-tree indexing and an undelete feature. At the end, the compatibility option has prevailed, making Ext4 completely compatible with Ext3. Therefore, an upgrade option exists from Ext3 to Ext4, without any need to recreate the volume and copy all files over to the new Ext4 volume. You can mount an existing Ext3 volume as an Ext4 file system, allowing you to benefit from the more efficient engine that the Ext4 driver offers.

New features in Ext4
The most important limitation in Ext3, was the maximum size of files that could be used. Ext4 addresses this limitation by using extents. An extent is a contiguous group of blocks, and in Ext4, files can allocate extents instead of individual blocks. This makes allocation storage much more efficient, decreases fragmentation, and most important, allows for much larger files and volumes. The maximal file size in Ext4 is 16 TB, whereas the maximum volume size is even set to 1 EB (that is 1024 x 1024 x 1 TB). The use of extents is not the only method that Ext4 uses to decrease chances of fragmentation, another feature added to accomplish this goal is preallocation. This means that blocks can be reserved, even if they are not used immediately. Related to that, is the delayed allocation feature, which means that the actual writing of files is delayed until the last possible moment, which simultaneously increases performance and decreases fragmentation.

Migrating from Ext3 to Ext4
Migration from Ext3 to Ext4 is rather easy; just mount the Ext3 file system as an Ext4 file system, using mount -t ext4 /dev/something /somewhere. This will automatically start using Ext4 features on the old Ext3 file system. There is a caveat though: if you do this, there is no way back. Once a file system uses specific Ext4 features, you cannot use it as an Ext3 file system anymore. Hence, you shouldn’t forget to modify your /etc/fstab to make sure that in the future your old Ext3 file system is mounted as Ext4 automatically after a system reboot.

Ext4 is the long awaited successor of the Ext3 file system. Since December 25, 2008, support is official in the Linux kernel. As migration is easy, and performance benefits are important, it’s a good idea to start testing your migration from Ext3 to Ext4.

ABOUT THE AUTHOR: Sander van Vugt is an author and independent technical trainer, specializing in Linux since 1994. Vugt is also a technical consultant for high-availability (HA) clustering and performance optimization, as well as an expert on SLED 10 administration.

Zimbra and Alfresco Go to Peru

One of the great things about being an open source company is that we have a passionate community that goes beyond the boundaries of any one location (Zimbra HQ, for example), with community members that participate and contribute from all over the globe.  We saw this early on with the help the community gave us for international translations,  and several of our early partners hailed from as far as South Africa, Brazil and Germany.

So in December when the Ministerio de Vivienda – the  Ministry of Housing in Lima, Peru – began looking for new options to replace their expensive proprietary software with lower-cost, open source alternatives, it came as no surprise that the open source community eventually led them to Software Libre Andino, a Zimbra / RedHat distributor in Peru who helped replace their outdated systems with modern ones, including Zimbra for collaboration and Alfresco for document management.

The Ministerio de Vivienda, which is responsible for all the housing, construction and sewer systems in Peru, has a mission to improve access to adequate housing and basic services to all the citizens of Peru. Saving the government money is definitely one reason for the switch to Zimbra, but another important factor in their decision to deploy open source solutions is they found that open platforms allow their users to easily integrate and build new solutions on top of this foundation.

In this case they were able to deploy the Alfresco Zimlet created by Zimbra community members and allow a simple way for employees to store documents that are attached in email on the Alfresco server, and in turn select documents from the Alfresco server and attach them to a Zimbra email. Simple, inuitive integrations like these make it easy for government agencies or companies to invest in multiple open source products to meet their needs, instead of choosing proprietary options.

We love to hear stories of how Zimbra and open source technologies travel the globe – if you have any stories you want to share, drop us a line.

(Below: Save attachment to Alfresco and add an attachment to Zimbra from Alfresco).

Save to Afresco

Add from Alfresco

Zimbra Gallery Pages:
Save in Alfresco Zimlet
Alfresco Zimlet
Alfresco Zimlet Peru

Giảm IO load, tăng tốc đọc/ghi dữ liệu trên Linux Desktops

Hiện các thiết lập mặc định của file system trong Linux hướng đến tính toàn vẹn dữ liệu hơn là tốc độ, do vậy việc sử dụng đối với các hệ thống thiếu RAM, cần sử dụng nhiều swap, sẽ bị chậm đi. Đối với một hệ thống Linux desktop thì yếu tố tương tác quan trọng hơn số dữ liệu được throughput trong một giây.

Chúng ta có thể thực hiện một số điều chỉnh tham số sau để giảm IO load, đảm bảo tốc độ tương tác với hệ thống trong mọi điều kiện:

  1. Chỉnh sửa file /etc/grub.conf, trong phần tham số khởi động kernel:
    kernel /vmlinuz- ro root=/dev/VolGroup00/LogVol00 rhgb quiet elevator=anticipatory rootflags=data=writeback
  2. Chỉnh sửa file /etc/fstab, thêm tham số “noatime” vào sau tham số “default“.
    /dev/VolGroup00/LogVol00 / ext3 defaults,noatime 1 1
  3. Reboot.

The New Version of, the World’s Leading Free Office Software, is Now Available for Download

The 3.1 free office software released today contains a raft of new features voted for by users, including much improved on-screen graphics and improvements to all its components. The software is available as a free download via the website.

Edinburgh, UK (PRWEB) May 7, 2009 — The Community today announced the general availability of 3.1, a significant upgrade to the world’s leading open-source office productivity suite. Since 3.0 was launched last October, over 60 million downloads have been recorded from the website alone. Released in more than 90 languages and available as a free download on all major computing platforms, 3.1 looks set to break these records.

The Community is listening to its users. Users of previous versions of were asked to vote for their ‘most desired’ new features, and this wish list helped shape the new release. The new release also includes a feedback mechanism where users can opt-in to supply feedback automatically to the developers about how they use

The biggest single change (half a million lines of code!) and the most visible is the major revamp of on-screen graphics. Techies call it anti-aliasing – users just appreciate how much crisper graphics are on screen. The improved look extends to other subtle changes, such as: how images display when they are being dragged, how selections of text are highlighted, and even adding the ability to overline text.

New core features include:

Writer (word processing)

  • Improvements to comments: reply feature now supports ‘conversations’
  • Further grammar checker integration
  • Outline levels within paragraphs for complex documents

Calc (spreadsheet)

  • Hot hints for formulae, with new and improved formulae available
  • Improved sorting
  • More performance bottlenecks removed
  • The zoom slider added to the status bar
  • Rename sheets with a double-click

Chart (graphics engine)

  • Flexible positioning of axes for scientific and educational users
  • Flexible handling of “missing” data points

Impress (presentation)

  • Font size buttons

Base (database)

  • SQL syntax highlighting
  • Easier deployment of macro applications

Internationalization and Localization

  • Improved support for bidirectional scripts
  • New locale support

Behind the scenes, also now has a more capable file locking mechanism, enabling users to share files safely in a multi-user, multi-platform environment.

“ 3.1 demonstrates that we are listening to our users, and thanks to the long term commitment from our sponsors, we can invest the time and effort to make significant changes to the software,” said John McCreesh, Marketing Project Lead. “ has all the features users want, it’s easy to use and free. We urge everyone to download and try it today.”

Download 3.1 for free

Guide to new features

Reset mật khẩu “root”

Nếu “lỡ” quên mật khẩu “root”, bạn có thể theo các bước sau để reset mật khẩu:

  1. Vào Single User Mode:
    • khởi động lại máy chủ.
    • khi màn hình hiện chọn hệ điều hành (hoặc kernel) để boot, nhấn phím “A” để vào chế độ nhập tham số kernel.
    • nhập thêm ” 1″ (dấu cách + chữ “1”); Enter.
    • máy sẽ boot vào Single User Mode mà không cần gõ mật khẩu.
  2. Đổi mật khẩu: bằng lệnh “passwd”; gõ mật khẩu 2 lần.
  3. Reboot lại như bình thường.

Note: cách này chỉ thực hiện được khi bạn ngồi trước bàn phím máy chủ.

Openfire 3.6.4 has been released

We are happy to announce a new release of Openfire. The new release includes an important security fixe. Existing installations should update to this version. The complete set of changes can be found here.

Download Openfire from:


Openfire Team

ZCS 5.0.16 Released

We are pleased to announce: Version 5.0.16 of the the Zimbra Collaboration Suite.

Key Enhancements:
30163 – zimbra-zimbra migration via tar formatter (bundled zmztozmig tool)
35574 – command specifically to create an alias domain (zmprov createAliasDomain)
37259 – Enable batched indexing by default (performance gain)
37260 – Make apache based convertd the default (for new installs)
36011 – Provide user agent to custom auth modules
36408 – add ZM_AUTH_TOKEN in ZCO Cookie header

Notable Fixes:
35459 – Cannot revoke share with Public
32536 – Zimbra too trusting of MIME-type sent by client
35523 – time in appointment details inconsistent with DST time in summary views
35521 -CalDav performance improvement Plus fixes to item deletion (37517) & calendar creation (36968).
35510 – update jetty to include fix for jetty-439

(Further details on PMweb.)

As always, make a backup before upgrading: Backup and Restore Articles – Zimbra :: Wiki

5.0.16 Network Edition Release Notes

5.0.16 Network Edition Downloads

5.0.16 Open Source Edition: Release Notes & Downloads

Be sure to subscribe to the blog for the latest – enjoy this release!
-The Zimbra Team