Zextras Backup strategy advice
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Thread: Zextras Backup strategy advice

  1. #1
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    Zextras Backup strategy advice

    We use Zimbra Open Source Edition as the mail server for our business. I have recently installed Zextras suite trial and have been trying to figure out a backup strategy that will minimise our message loss in the event of a server or disk failure. I’ll explain our setup and my thoughts on the backup options, if I’ve got something wrong then please let me know. I would welcome any advice from Zextras or other forum members.

    We are using Centos 5.3 x64, Zimbra 7.1.3 and Zextras 1.2.5, this runs in a VM on a Citrix XenServer 5.5 server. This is a default OS, Zimbra and Zextras install with everything on a single disk, we have less than 10 email accounts and our /opt/zimbra tree is only around 16GB and 4.4GB of that is under /opt/zimbra/backup/zextras.

    At the moment I take a snapshot each night of the entire VM that Zimbra runs in so I have a full backup of the OS, Zimbra, Zextras suite and all the Zimbra/Zextras data. Using XenServer it only takes a few seconds to take the snapshot and I then copy it to a remote server.

    From the Zextras Backup documentation it appears to me that the Real Time Scanner provides a great facility to retain and restore deleted messages, folders, accounts etc. which is exactly what email admins need most of the time. However if you have a default Zimbra and Zextras installation and you lose the server or the disk that Zimbra and Zextras is installed on then you lose your mail store and the Zextras backup data! I did see a suggestion by a Zextras representative in another forum post that the files by default written to /opt/zimbra/backup/zextras could be written instead to a RAID SAN storage device but as another forum member pointed out many people will not have this facility available. I also note that Zextras “strongly advice against the use of network shares (or any high access latency solution) as the main ZxBackup store”. If I want to connect /opt/zimbra/backup/zextras to a remote file system what sort of performance is required and will Zextras Backup handle intermittent availability? If I do have a fast remote file system for Zextras Backup would I just restore my VM snapshot, reconnect the remote file system and use the Zextras admin tools to restore emails in the event of a disaster?

    I looked at the Zextras External backup facility which takes a full backup of selected mail domains. However this facility is only available interactively through the Zextras admin screen, the CLI or by writing and scheduling your own scripts, also it will only take a full backup of the selected domains. If this facility were used to backup all mail domains each night it would result in a lot of data being written and the same data night after night. I already have this data and more in my VM snapshot. While Zextras External backup is not useful to me I think it would be more useful and more usable if we were able to schedule the External backup from within Zextras admin and it allowed incremental as well as full backups which could be written to a single GZIPed file rather than a tree of files.

    Currently if I lose the server through a hardware failure or a site disaster like a fire my best way back looks to be to restore my VM snapshot as that has the OS, Zimbra, Zextras and all the data as at the previous night however this would mean I lose all the emails and Zimbra operations since the snapshot was taken.

    I would like to not lose email in the event of a server failure so I am now looking at Zimbra server Live Sync, see Server Live sync - Zimbra :: Wiki
    Would Zextras backup Real Time Scanner work with this solution? Would Zextras like to add a remote near real time backup store option to Zextras Backup that would work over slow or intermittent links?

  2. #2
    ZeXtras Community Manager ZeXtras Employee Cine's Avatar
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    Hello Stuart,welcome to the forums!Thank you for your feedback, it's really appreciated...
    Quote Originally Posted by Stuart View Post
    We use Zimbra Open Source Edition as the mail server for our business. I have recently installed Zextras suite trial and have been trying to figure out a backup strategy that will minimise our message loss in the event of a server or disk failure. I’ll explain our setup and my thoughts on the backup options, if I’ve got something wrong then please let me know. I would welcome any advice from Zextras or other forum members.We are using Centos 5.3 x64, Zimbra 7.1.3 and Zextras 1.2.5, this runs in a VM on a Citrix XenServer 5.5 server. This is a default OS, Zimbra and Zextras install with everything on a single disk, we have less than 10 email accounts and our /opt/zimbra tree is only around 16GB and 4.4GB of that is under /opt/zimbra/backup/zextras.At the moment I take a snapshot each night of the entire VM that Zimbra runs in so I have a full backup of the OS, Zimbra, Zextras suite and all the Zimbra/Zextras data. Using XenServer it only takes a few seconds to take the snapshot and I then copy it to a remote server.
    Ok, pretty standard setup... I usually prefer to have all partitions separated in different VHDs, better performance scaling when expanding the infrastructure
    Quote Originally Posted by Stuart View Post
    From the Zextras Backup documentation it appears to me that the Real Time Scanner provides a great facility to retain and restore deleted messages, folders, accounts etc. which is exactly what email admins need most of the time. However if you have a default Zimbra and Zextras installation and you lose the server or the disk that Zimbra and Zextras is installed on then you lose your mail store and the Zextras backup data! I did see a suggestion by a Zextras representative in another forum post that the files by default written to /opt/zimbra/backup/zextras could be written instead to a RAID SAN storage device but as another forum member pointed out many people will not have this facility available. I also note that Zextras “strongly advice against the use of network shares (or any high access latency solution) as the main ZxBackup store”. If I want to connect /opt/zimbra/backup/zextras to a remote file system what sort of performance is required and will Zextras Backup handle intermittent availability? If I do have a fast remote file system for Zextras Backup would I just restore my VM snapshot, reconnect the remote file system and use the Zextras admin tools to restore emails in the event of a disaster?
    The advice against network shares or other high-latency storage solution is mainly for servers with a large number of operations per-second and refers to CIFS shares and non-local NFS shares or SSHFS mountpoints. The Real Time Scanner is based on a First-in-first-out queue, so adding a large number of operations to the queue while processing a low number of operations due to latency issues will cause you to lose a high number of queued operations in case of a system crash/emergency stop, thus undermining the effectivity of the real time backup.There is no "fixed rule" regarding the actual requirements for a remote filesystem, because such requirment depend on too many different factors.I think that the best way to see if your remote storage is adequate to be used as the ZxBackup store is to run a simple test: switch the backup path to the remote storage and monitor the operation queue using the ZeXtras CLI. If the number of queued operation is too high, ZxBackup will also send a warning notification (when the queue reaches 2500 operations).
    Quote Originally Posted by Stuart View Post
    I looked at the Zextras External backup facility which takes a full backup of selected mail domains. However this facility is only available interactively through the Zextras admin screen, the CLI or by writing and scheduling your own scripts, also it will only take a full backup of the selected domains. If this facility were used to backup all mail domains each night it would result in a lot of data being written and the same data night after night. I already have this data and more in my VM snapshot. While Zextras External backup is not useful to me I think it would be more useful and more usable if we were able to schedule the External backup from within Zextras admin and it allowed incremental as well as full backups which could be written to a single GZIPed file rather than a tree of files.
    I honestly can say that there is a really low chance of seing an additional "alternative" backup mode such as the Full+Incremental one in ZeXtras Backup.Our aim during development was to provide not only a reliable backup solution, but also one flexible enough to be customized by users according to their need.In your case, if the remote storage is not suitable to be the ZxBackup Store, I'd suggest an rsync of the backup path to the remote storage instead of a nightly export . This way you'll solve the "writing the same data night after night" problem and also lower the chance of losing the backupped data due to unavailability of the remote storage (losing the connection while rsyncing a GZip file will render the file useless leaving you with no data, while losing the connection during the rsync of a folder tree leaves you with coherent data).
    Quote Originally Posted by Stuart View Post
    Currently if I lose the server through a hardware failure or a site disaster like a fire my best way back looks to be to restore my VM snapshot as that has the OS, Zimbra, Zextras and all the data as at the previous night however this would mean I lose all the emails and Zimbra operations since the snapshot was taken. I would like to not lose email in the event of a server failure so I am now looking at Zimbra server Live Sync, see Server Live sync - Zimbra :: Wiki Would Zextras backup Real Time Scanner work with this solution? Would Zextras like to add a remote near real time backup store option to Zextras Backup that would work over slow or intermittent links?
    As I said, slow links are a problem only in high operations-per-seconds situations, while the risk of an intermittent link can be easily overcome by running a SmartScan operation, which is specifically designed to fix any inconsitency in the backup.I really don't know if ZeXtras Backup would work on a "Live Sync" infrastructure, I'm very positive it would but being a non-standard setup I'd have to run some tests...Have a nice day,Cine

  3. #3
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    Hi Cine,

    Thank you for the quick reply, if your support is this good for trial users then I'm encouraged to buy the suite. Given your advice and my desire to lose no email in the event of a disaster I'm going to continue using Zextras Backup Real Time Scanner to the local disk and then test using "Live Sync" to another server. I can't test this immediately but I will let you know how I get on.

    Stuart

  4. #4
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    How did your testing go Stuart as I shall be looking to do a similar thing. Thanks.

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