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  1. #1

    SAN - fail over / high availability

    Hi,

    we are currently planning to implement SAN to our enviroment - VPS hosting.

    Al VPS should be placed on the SAN - iSCSI connected to be able live motion etc.


    Currently we are fighting with idea of Failover/High avalability.
    There has been rumors that dual controller SAN from HP/DELL are much more problematic than single controller versions.

    We are also thinking about running some opensource like OpenFiler/FreeNAS/OpenSolaris or NexentaStore on supermicro boxes with SATA or single RAID controller.

    But in that case - how make the iSCSI target highly available? Mirroring of the data/space is pretty easy with DRBD or ZFS but when one SAN box goes down, there should be no interruption in iSCSI targe service - no IP change etc..

    Any help would be greately appreciated

    Thanks

    Peter

  2. #2
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    You need to go to network raid with multiple boxes that are connected to redundant network and power.

    You can do this with virtualized storage. The VSA lefthand units from hp allow you to fully distribute the storage and the controller nodes run in fault tolerant mode. The units themselves have a raid setup to improve the uptime of the individual unit but then the data is written across the units as well to ensure continuous operations in the event of an entire chasis failure. There are a few that can do this level of redundancy including EMC and 3par. Make sure you have redundant network connections from your servers as well or your storage will be up and your servers wont access it due to network outages. This includes switching infrastructure as well - all it takes is one single point of failure.




    Quote Originally Posted by xenware View Post
    Hi,

    we are currently planning to implement SAN to our enviroment - VPS hosting.

    Al VPS should be placed on the SAN - iSCSI connected to be able live motion etc.


    Currently we are fighting with idea of Failover/High avalability.
    There has been rumors that dual controller SAN from HP/DELL are much more problematic than single controller versions.

    We are also thinking about running some opensource like OpenFiler/FreeNAS/OpenSolaris or NexentaStore on supermicro boxes with SATA or single RAID controller.

    But in that case - how make the iSCSI target highly available? Mirroring of the data/space is pretty easy with DRBD or ZFS but when one SAN box goes down, there should be no interruption in iSCSI targe service - no IP change etc..

    Any help would be greately appreciated

    Thanks

    Peter
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  3. #3
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    Texas
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    Quote Originally Posted by sailor View Post
    You need to go to network raid with multiple boxes that are connected to redundant network and power.

    You can do this with virtualized storage. The VSA lefthand units from hp allow you to fully distribute the storage and the controller nodes run in fault tolerant mode. The units themselves have a raid setup to improve the uptime of the individual unit but then the data is written across the units as well to ensure continuous operations in the event of an entire chasis failure. There are a few that can do this level of redundancy including EMC and 3par. Make sure you have redundant network connections from your servers as well or your storage will be up and your servers wont access it due to network outages. This includes switching infrastructure as well - all it takes is one single point of failure.
    The VSA software is a very nice package but it does have it downsides.

    1: Cost it is very expensive. My last quote we where looking at around 5K$ in license fee's per VSA instance.

    2: Limits on the size. When I eval'd the VSA package 1 year ago it had a limit of 2TB per VSA instance meaning you where severly limited on the number of drives you would run in each node.

    3: Resources consumed to operate. The VSA software when I reviewed it required 2 VCPU and 2GB of RAM per instance to operate meaning you are loosing quite a bit of resources on each node if you plan to use the VSA package to expose the DSA storage in each host to the rest of your environment.

    There is other turnkey solutions on there that will do what the OP is looking for and more in the sense of xen type environments with shared storage to be used for 'HA' / 'Failover' / 'VMotion' or whatever you wish to call it using purely commodity hardware and storage devices with no specialized storage networking devices required either.

  4. #4
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    Quote Originally Posted by Cirrostratus View Post
    The VSA software is a very nice package but it does have it downsides.

    1: Cost it is very expensive. My last quote we where looking at around 5K$ in license fee's per VSA instance.

    2: Limits on the size. When I eval'd the VSA package 1 year ago it had a limit of 2TB per VSA instance meaning you where severly limited on the number of drives you would run in each node.

    3: Resources consumed to operate. The VSA software when I reviewed it required 2 VCPU and 2GB of RAM per instance to operate meaning you are loosing quite a bit of resources on each node if you plan to use the VSA package to expose the DSA storage in each host to the rest of your environment.

    There is other turnkey solutions on there that will do what the OP is looking for and more in the sense of xen type environments with shared storage to be used for 'HA' / 'Failover' / 'VMotion' or whatever you wish to call it using purely commodity hardware and storage devices with no specialized storage networking devices required either.
    1. That is retail - you can do better than that - but remember this is very high end storage with all the enterprise tools that come with it. there are definately cheaper solutions available.

    2. It supports 10 tb as of 90 days ago.

    3. I would not suggest running it on all of the devices out there that are also supporting vms' - build dedicated boxes that will are your storage servers.
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  5. #5
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    Quote Originally Posted by xenware View Post
    There has been rumors that dual controller SAN from HP/DELL are much more problematic than single controller versions.
    What rumor do you hear? Which models? We have Dell/Equallogic PS5500E running on two controllers. Failover was a non issue.

    No experience with HP/Lefthand. If you want to achieve redundancy over separate geographical locations you can check into Lefthand Network.
    Fluid Hosting, LLC - Enterprise Cloud Infrastructure: Cloud Shared and Reseller, Cloud VPS, and Cloud Hybrid Server

  6. #6
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    Quote Originally Posted by FHDave View Post
    No experience with HP/Lefthand. If you want to achieve redundancy over separate geographical locations you can check into Lefthand Network.

    Correct - but there are distance limitations on this. I think 50-60 ms is the max. But it is cool stuff.
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  7. #7
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    Quote Originally Posted by xenware View Post
    Hi,


    Currently we are fighting with idea of Failover/High avalability.
    There has been rumors that dual controller SAN from HP/DELL are much more problematic than single controller versions.
    Considaring Dell/IBM/LOTS of other companies All use LSI controllers alike and/or they all for the most part even on the bigger IBM SANs are all OEMS from _the_real_ manufacture I highly doubt the controller failures are true.

    Quote Originally Posted by xenware View Post
    We are also thinking about running some opensource like OpenFiler/FreeNAS/OpenSolaris or NexentaStore on supermicro boxes with SATA or single RAID controller.
    Please stay away from openfiler and freenas. If worse case use Opensolaris I cannot comment on nexentrastore but I wouldn't suggest it.
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  8. #8
    Currently my iSCSI solution is StarWind. As I know soon they`ll support HA. I'm fully satisfied with their product and service for now, so I guess HA will be good too.
    Regards.

  9. #9
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    dual HBA does get problematic , we had HP environment in which part of the cluster was actually stable however never required to failover within HBA, however there was another nas segment which got into hung state once in a while where the actual controllers has to be reset

  10. #10
    Join Date
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    Why not nexentastor? We're considering it since it solves alot of the vendor issues (licensing and other stuff).

    I know their new release had the real failover but I haven't had time yet to test it out.

    From all indication and impression it looks impressive.

  11. #11
    Quote Originally Posted by Spudstr View Post
    Please stay away from openfiler and freenas.
    Any specific reasons?
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