Forum Discussion

SteveLaw's avatar
SteveLaw
Level 5
9 years ago

Multipathing software required for ESX datastores SAN volumes?

Hi, I have a NBU VMWare proxy server, NB 7.5.0.6 on Windows 2008, that has SAN visibility of the ESX datastores and has been happily backing up VMs to Data Domain for over a year. Recently an addi...
7.5
Backup and Recovery
NetBackup
Windows Server (2003-2008)
  • Michael_G_Ander's avatar
    Michael_G_Ander
    9 years ago

    @Steve can tell you that I have used vmware backup with multipathing in Netbackup 7.5, without issues other than the SAN restore thing which had to do with the api rather than the number paths.

    Think you best bet of resolving this is together with your SAN, Windows & VM administrator

    Looking at the diskpart output the disks 35,59,83,107 could be the same LUN/datastore again assuming 4 paths through the SAN fabrics, and that disk 11 is from the old VM farm.

    Just checked on a server, the path to the "low" level disk drives is:

    Computer Management -> System Tools -> Device Manager -> Disk Drives

     

  • sdo's avatar
    sdo
    9 years ago

    From these posts:

    https://www.veritas.com/community/forums/linux-vmware-backup-host-multi-pathing-support

    https://www.veritas.com/community/forums/suse-linux-112-vmware-backup

    ...it is clear that the the document "DOCUMENTATION: Support for NetBackup 7.x in virtual environments", here:

    https://www.veritas.com/support/en_US/article.TECH127089

    ...used to list that there were some restrictions around multi-pathing for NetBackup with some Linux OS.  However this document no longer carries any reference to this, and so would appear to imply that these restrictions are no longer valid (but probably one can only assume for the most recent versions of NetBackup - because it doesn't say when the restrictions were lifted).  I'm aware that similar restrictions used to once also exist for Windows based VMware backup hosts.  But when was that restriction lifted?  And for which version of NetBackup?

    .

    And yet at the time of the postings, from the version of the doc at the time, it was clear that multi-pathing was supported for Windows based VMware backup hosts - but which versions?

    .

    Do you see how your question is very difficult to answer because you are on v7.5.0.6 and so it's not easy to determine whether your version matrix can support multi-path.  Maybe it can, and so all you need to do is install a DSM and/or multi-path driver and you'll be ok.

    But I don't know this for sure.  Maybe it does, maybe it doesn't for your old version.

    Hence I was suggesting to dig back through the old VDDK release notes to see when the support was introduced by VMware.

    Remember, this isn't a NetBackup question per-se, it's a VMware "interop" question.

Steve_Law's avatar
Steve_Law
Level 4
9 years ago

Hi,

I raised a call with Netbackup and they have found that the cause of the backup failures is NOT the multipathing issue and the offline disks. The problem is incompatibility of our Netbackup 7.5.0.6 with the new ESX farm on which the vCenter server is v6.0. The error in the vxms debug logs shows this: 

....backline colleague confirmed that because of incompatibly, the handshake will not complete.
 
VXMS log snippit:
 
10:04:12.0109 : g_vixInterfaceLogger:bvix.cpp:1835 <INFO> : diskLibPlugin: 2016-02-16T10:04:12.109Z [01504 error 'Default'] SSLStreamImpl::DoClientHandshake (0000000007c37930) SSL_connect failed with Unexpected EOF
 
10:04:12.0109 : g_vixInterfaceLogger:bvix.cpp:1835 <INFO> : diskLibPlugin: 2016-02-16T10:04:12.109Z [01504 trivia 'Default'] Setting error in state 1 : class Vmacore::Ssl::SSLException(SSL Exception: Unexpected EOF)
 

Therefore I need to upgrade Netbackup master and media servers to v7.6.1 or more. On the multipathing front I asked "It seems that originally Windows servers running as Netbackup VM proxies with San access to ESX datastores DID NOT support multipathing, but more recently they do. Can you tell me which versions, and if multipathing is supported for a 7.5.0.6 vm proxy server?". They replied:

"NetBackup 7.5.0.6 or NetBackup 7.6.1.2 should be fine.  It is the OS that handle multi-pathing.  So NetBackup rely on the OS for this function."

So it seems that I should be able to install multipathing software without an issue on the VM Proxy server that can see the ESX datastores. (Although it will be nerve-wracking - I'm still worried that somehow making any changes on these servers will corrupt the datastores and kill a hundred vms...!) 

Thanks for all your help and suggestions! I'll split the resolution between sdo and Michael.