Data Protector 7.03 Linux VEPA Unable to use SAN path & selects always LAN Path

  • KM00814490
  • 24-Mar-2014
  • 24-Mar-2014

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Problem Summary: VEPA Unable to use SAN path, backups going via LAN instead of SAN Solution Summary: Issue lied with VMWARE side, Firmware of VMWARE Infrastructure was upgraded and VMWARE Datastores were recreated.


Environment Details:

VDDK version and build details: VDDK for Linux 5.1.0

Kind of backup being run:  (DiskLevel/FileLevel) vStorage of Virtual Machine

VDDK proxy details - OS/Architecture: Linux 2.6.32-131.0.15.el6.x86_64 #1 SMP Tue May 10 15:42:40 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux.

Target Proxy details - OS/Architecture: Same as that of VDDK Proxy above.

Backup host is Physical RHEL 6.1 machine, Virtual Center Server is Windows 2008 Server, DP CM server is HP-UX 11.31

Data Protector VM backups happening over LAN instead of SAN

Old Firmware on VMWARE Infrastructure

This is Linux VDDK.

Footprints inside Debugs showed:

Available transport methods: file:san:hotadd:nbdssl:nbd

[ 99] 2013-12-05 16:05:19 ("/integ/vep/vepa/Plugins/Vmware/VmwareHelpers/DiskUtils/VddkUtil.cpp $Rev: 39407 $ $Date:: 2013-10-08 14:09:02":739) A.07.00 b105
[ 99] <<=== (6) }  /* getUsedTransportMethod */
[ 99]
[ 20] [getUsedTransportMethod] Returning:
value='nbdssl'   ---> This is where "SAN" must appear.


Root cause is the configuration of VMware Datastore and/or luns.
To be able to use the SAN transport mode
1: disk needs to be presented in R/W mode
2: disk must be on-line and registered by the system
3: multi-path disks should be configured with multipath driver.

 The LUN should be visible at OS level, it is the VMware software which will detect the LUN as a VMFS file system and allow the SAN transport at condition the Lun was presented as R/W.


Trivia Transport Logs Collection Procedure available at:

Trivia Logs Collection Procedure on ESXi Server available at:

For Multipath in Linux Environment:

Even a CBT (Changed Block Tracking) backup should pass over SAN.

The principle here is that the VMware software contacts the ESX to query the layout.
Then it tries to read those LUNS using the SAN on the Linux host.
The reason may be the multipath configuration on Linux.
If a multipath device is presented then only one path should be seen in the Linux host.

On linux there is a fdisk –l command to verify this.

fdisk -l

fdisk -l, multipath –ll , cat /etc/multipath.conf outputs were verified from the inhouse working and workign and non-working customer's environments.

Following were the activities performed which resolved this issue.

1)      Firmware upgrade of the whole Vmware infrastructure
2)      Re-creation of the datastore.