Comparing HA-Lizard and XenServer HA


  • Service Provider

    Recently @DustinB3403 and I were discussing HA-Lizard for XenServer for HA needs and I thought that it would be good to have a discussion around comparing the two systems.

    HA-Lizard makes a lot of claims around their features but many of these features are at least partially in XenServer natively too. So it is very confusing to determine which systems have which features and what truly is a benefit of one over the other.

    It would be great to have someone trial both in a lab and see how they stack up. Get some real world, third party, outside view of the two and compare.


  • Service Provider

    Ah, I found it. HA-Lizard is actually using DRBD to do the replication work. So that is good, it would have been incredibly silly to not use that. But this means it is using the storage that we already had. So the additional functionality cannot be coming from this portion:

    http://www.halizard.com/images/pdf/iscsi-ha 2-node cluster howto_1.5_final.pdf



  • For anyone looking for the specific requirements for this check page 8 of the HA-Lizard pdf.



  • @scottalanmiller said:

    HA-Lizard makes a lot of claims around their features but it seems that they leave out the fact that much of that functionality is built into XenServer.

    Was this always the case or did XS play "catch up" with their latest release?


  • Service Provider

    @Danp said:

    Was this always the case or did XS play "catch up" with their latest release?

    It was some time ago, when XS went open source with 6.2, all of those features came along with the "freeing" of the platform.



  • Thanks for the welcome note.
    Here are some clarifying points on what HA-Lizard is:

    The HA-Lizard project is currently made up of three applications:
    HA-Lizard, iSCSI-HA and a “noSAN” script which automatically creates a cluster based on our reference design for a 2-node HA cluster

    HA-Lizard is an HA application specifically written for XenServer (and older XCP) environments. It provides a similar feature set when compared with XenServer HA with a few exceptions.

    • Predictable HA is provided in a 2-node pool environment
    • Can be used in single host deployments as a VM watchdog
    • Provides fencing and STONITH

    iSCSI-HA is a storage management application which manages DRBD, an iSCSI target, floating IP, etc.. When coupled with HA-Lizard, it allows users to create 2-node HA clusters using local storage. VMs are free to run on either host.

    The net result is HA-Lizard + iSCSI-HA creates a 2-node highly available cluster which is ideally suited for small cluster deployments AND single application deployments that need to run in a highly available environment in a compact and cost effective manner.

    Most of our installations are HA-Lizard + iSCSI-HA. There is a reference design on the HA-Lizard site which details all of steps for building a cluster. An installer was also created to automatically install/configure ALL packages in minutes.

    The project is extensively documented on the HA-Lizard web site


  • Service Provider

    what's the word on this? i'm about to move a client to xen simply for the fact that esxi free doesn't offer any sort of replication/DR very simply.



  • @hubtechagain said:

    what's the word on this? i'm about to move a client to xen simply for the fact that esxi free doesn't offer any sort of replication/DR very simply.

    I would move them just for the functionality of Xen. You aren't required to use Xen and HA-Lizard together.

    Using NAUBackup you can make scheduled VM backup's to an NFS/CIFS server and XenServer Patcher apply patches from the CLI.



  • Dustin,
    Does NAUBackup have incrementals? It does not appear so in the documentation.



  • @Dashrender said:

    Dustin,
    Does NAUBackup have incrementals? It does not appear so in the documentation.

    No, it is strictly a running state backup tool. It does however cleanup after it's self. Removing the Snapshot from Xen's local storage, and will remove old backup's after the default of 4. (this default can be changed)

    So it's quiet nifty in what it offers for free. For incremental (file level backups) I'd use a separate tool (especially if on a Windows File server) such as Shadow Protect.



  • Or Amanda, or Create Synchronicity to create incremental backups off host.

    I haven't used either at a large scale solution, Create Synchronicity works great though on any given users system to make incremental backups.


  • Service Provider

    @hubtechagain said:

    what's the word on this? i'm about to move a client to xen simply for the fact that esxi free doesn't offer any sort of replication/DR very simply.

    HA-Lizard might be a really good choice, lots of features and.. FREE.


  • Service Provider

    @DustinB3403 said:

    No, it is strictly a running state backup tool. It does however cleanup after it's self. Removing the Snapshot from Xen's local storage, and will remove old backup's after the default of 4. (this default can be changed)

    If you store images on a system with block-level dedupe it will act much like an incremental.



  • @scottalanmiller said:

    @DustinB3403 said:

    No, it is strictly a running state backup tool. It does however cleanup after it's self. Removing the Snapshot from Xen's local storage, and will remove old backup's after the default of 4. (this default can be changed)

    If you store images on a system with block-level dedupe it will act much like an incremental.

    It kicks the VM offline to perform a snapshot, so if you're willing to take your VM's down for that given length of time on schedule every so often I suppose it could.

    Seems like overkill to me.



  • @DustinB3403 said:

    @scottalanmiller said:

    @DustinB3403 said:

    No, it is strictly a running state backup tool. It does however cleanup after it's self. Removing the Snapshot from Xen's local storage, and will remove old backup's after the default of 4. (this default can be changed)

    If you store images on a system with block-level dedupe it will act much like an incremental.

    It kicks the VM offline to perform a snapshot, so if you're willing to take your VM's down for that given length of time on schedule every so often I suppose it could.

    Seems like overkill to me.

    Say what? it shuts the VM down?

    So much for years of uptime.
    ;)



  • Years of uptime, as awesome as it sounds doesn't really work.

    It sets the VM to a suspend state while it build the backup file. (At least this is what NAUBackup does).

    So technically speaking your Uptime counter should still continue, as far as the VM knows.



  • @DustinB3403 said:

    Years of uptime, as awesome as it sounds doesn't really work.

    It sets the VM to a suspend state while it build the backup file. (At least this is what NAUBackup does).

    So technically speaking your Uptime counter should still continue, as far as the VM knows.

    I take it you can't use that on things like SQL and Exchange then?



  • I haven't had anything to try yet that is heavily used. We have our Asset management system which is built on a SQL Database, and that gets backed up weekly without issue.

    But there are only 2-4 people accessing the database at a time, at the most.



  • I was under the impression that there was only a blip in the machine's activity as the snapshot was taken (this usually doesn't take but a second or two, right?).



  • Just testing now, it takes maybe 3-5 seconds to run per VM in our environment.



  • And that is only the Snapshot portion, migrating it off host obviously takes a bit of time.



  • @DustinB3403 said:

    And that is only the Snapshot portion, migrating it off host obviously takes a bit of time.

    Sure, but other than using some resources shouldn't really be noticed by the VMs themselves.



  • @DustinB3403 After the snapshots are complete, the VMs should go back to running.



  • @dafyre Correct they do.

    Immediately after those first few seconds. The data transfer off host takes the longest amount of time to complete.

    I have 4 VM's that we backup (care about) that use 696GB of data, so the transfer time takes a bit.



  • @DustinB3403 How much does that affect the performance of the VMs that are running while your backups are being copied off?



  • I've never monitored them.

    The work is being done by Dom0, not the VM.

    And with the resources being statically assigned I can't imagine that there is much of a hit to the performance of the VM's them self.



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