ESXi

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  • 1.  Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 08, 2011 02:32 PM

    How do we protect against VMFS/VMDK corruption?  Let's assume the  worst: software glitch, write cache failure, whatever.  It gets ruined.

    I know the SAN vendors have solutions, but... hey, I'm poor, I can't afford that stuff.

    On a physical we have RAID hardware; usually the operating system boots and it doesn't even realize  it's on a raid/mirror.

    Do VMware drivers allow us to carry this concept over?  Mirrored VMDKs from different VMFS?  Fully mirrored VMFS?

    Not sure if I'm asking the obvious or the impossible here.

    Peace, love, and jelly beans.



  • 2.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 08, 2011 04:24 PM

    VMFS is basically a file system type (like FAT, NTFS, ...) which is used to format a partition on a (usually) already protected RAID system. This way the VMFS partition (the datastore) is already protected against a disk failure. The virtual disks are files on this datastore which can easily be backed up using free tools like ghettoVCB or commercial software (depending on your VMware licensing).

    André



  • 3.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 08, 2011 04:40 PM

    VMware ESXi does not support software RAID. If you want to have a mirrored drive you would need to have a hardware based RAID controller. Most embedded RAID controllers found on Desktop or hand built servers require a software component to provide the RAID functionality. These types of controllers, often referred to as fakeraid devices, are not supported under ESXi.



  • 4.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 08, 2011 06:55 PM

    You'll have to add an abstraction layer, probably a Virtual SAN Appliance (a software based SAN running in a VM).


    For example: Implement OpenSolaris, get ZFS and zVol protection of your underlying block data, present that via iSCSI/NFS to your ESXi box again.

    VMFS doesn't have any underlying technologies to protect against any of this, it is built with the idea of you implementing your technology of choice under it at the block/hardware level.



  • 5.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 08, 2011 10:09 PM

    With ESX 4.1 update 1 VDR is now free for more editions of ESX.

    Personally anything that gets your data to tape gets my vote.

    The cost of a backup strategy is generally much easier to take over the cost of the loss of data.



  • 6.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 10, 2011 12:16 AM

    Thanks for the guidance.  That helped my thoughts.  I have a lot of cheap iscsi units so I worry about these things.

    I love the idea of a ZFS built from several arrays.  I might try it out for kicks, I have a Solaris box on the san network.

    Of course, that box becomes a single failure point. And it could still corrupt the mirror/raid.  I had an AIX box do that recently.  Took it's job seriously, ruined both copies.

    I guess at the root of it all, that's the deal.  Any protection we lay on it is going to have it's limits.



  • 7.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 10, 2011 01:40 AM

    b0bzilla wrote:

    Thanks for the guidance.  That helped my thoughts.  I have a lot of cheap iscsi units so I worry about these things.

    I love the idea of a ZFS built from several arrays.  I might try it out for kicks, I have a Solaris box on the san network.

    Of course, that box becomes a single failure point. And it could still corrupt the mirror/raid.  I had an AIX box do that recently.  Took it's job seriously, ruined both copies.

    I guess at the root of it all, that's the deal.  Any protection we lay on it is going to have it's limits.

    As far as Solaris boxes go, I typically see head/passive units connected to disk enclosures to help prevent a single point of failure.



  • 8.  RE: Protecting against loss of a VMFS (without spending a lot of cake)

    Posted Sep 10, 2011 01:14 AM

    After reading this thread this really made up my mind. I really like the thought of VMFS. Thanks.http://www.imagicon.info/cat/5-59/1.gif