EMC PowerPath limitations

KB ID: 2771
Product: Veeam Agent for Linux
Version: 1.x, 2.x
Published:
Last Modified: 2018-09-19

Challenge

If a Linux server has EMC PowerPath devices attached, all the underlying block devices representing the network paths to the server will be included into the backup. Therefore, an extra amount of data will be created inside the backup file.

Cause

In the current versions of Veeam Agent for Linux, only the DM-Multipath based devices are detected as aggregated. All the block devices with underlying EMC PowerPath aggregated devices are also included into the backup file if ‘Entire machine’ backup mode is selected. 

EMC PowerPath support will be introduced in the future versions of Veeam Agent for Linux.

Solution

Configure Volume-level backup job in Veeam Agent for Linux and include only aggregated EMC PowerPath devices and regular block devices into the backup, do not include block devices representing the network paths of EMC PowerPath. In this case, no extra data will be stored inside the backup file, only the exact amount of real data. For example, in following output you may see EMC PowerPath aggregated device name and underlying devices:

[root@localhost ~]# powermt display dev=all
Pseudo name=emcpowerea
Symmetrix ID=000343607604
Logical device ID=07BA
Device WWN=60000980000262604497023030364553
state=alive; policy=SymmOpt; queued-IOs=0
==============================================================================
--------------- Host ---------------   - Stor -  -- I/O Path --   -- Stats ---
###  HW Path               I/O Paths    Interf.  Mode     State   Q-IOs Errors
==============================================================================
   6 lpfc                   sdef       FA 10f:00 active   alive      0      0
   5 lpfc                   sdcm       FA  6f:00 active   alive      0      0
   4 lpfc                   sdau       FA  7f:00 active   alive      0      0
   3 lpfc                   sdb        FA 11f:00 active   alive      0      0
In this example there are following devices:
 
/dev/emcpowerea – aggregated EMC PowerPath device
/dev/sdef, /dev/sdcm, /dev/sdau, /dev/sdb – underlying block devices representing the network paths
 
Accordingly, to mount table /dev/emcpowerea partitioned and mounted under /data folder:
root@localhost:~# mount | grep emcpowerea
/dev/emcpowereap1 on /data type ext4 (rw,relatime,errors=remount-ro,stripe=256,data=ordered)
In this case block device /dev/emcpowereap1 must be included into backup as shown on image below
User-added image
sdef, sdcm, sdau and sdb should be left unchecked.

If Veeam Agent backup job is managed by the backup server, you may configure the same via Veeam B&R console. For example, choose type ‘Volume level backup’ for your backup job:
User-added image

And enter the block device names or mountpoint paths as shown below:

User-added image
User-added image

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