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Netbackup 7.5 vmware backup SAN transport and slow backup speed

Created: 27 Aug 2012 | 8 comments
Henry Cheng's picture

I am doing VMware backup policy using a media server dedu pool(the disk LUN is on the 4G FC SAN). The datastore is on the FC SAN. I am getting the backup rate from anywhere 8Mbps to almost 100Mbps. I check the resouce monitor for both the media server and the VM, the network traffic is at about 1Mbps, so the traffic should be through SAN. However, the summary for the job indicates it is over LAN. Any idea what exact the transport type? or any way to improve the backup performance over SAN? I think the 4G SAN should provide much higher than the 100 Mbps speed. 

Best regards,


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Nicolai's picture

The transport type will always be LAN unless you are using fibre transport (FTL).

Assumption is the mother of all mess ups.

If this post answered your'e qustion -  Please mark as a soloution.

Douglas_A's picture

Have you already configured the Datastore luns to be visible to the VMBackup Host/Media Server?

You cannot use the SAN method unless you have them configured so windows can see them.

Best of Luck,


Please remember to mark the most valuable answer to your issue as the solution.

Mark_Solutions's picture

In the snapshot options of the policy the transport type should be shown as "san"

But as pointed out the datastore LUNS must be visible to the media server performing the backup (The VMWare Backup Host)

Hope this helps

Authorised Symantec Consultant

Don't forget to "Mark as Solution" if someones advice has solved your issue - and please bring back the Thumbs Up!!.

Henry Cheng's picture

1. the datastore LUNs are presented to the media server(VMware Backup Host).

2. I think only backup over FT media server for SAN client is shown "FT" for Transport, but backing up ESXi host is via VMware backup Host/media server over SAN should not be called FT.

3. I checked the job details that bptm waited times for full buffer is bptom delayed time is huge - sometimes 774K and 854K. I am using default "number_buffer_size" and "data buffer number". Is there anyone who did test before how we can adjust the setting to improve the backup performance.

Thanks again for your attention and help.


Mark_Solutions's picture

Transport type should be san, FT us different
Buffer tuning depends on if you are backing up to disk or tape - tell us the destination and we can advise

Open the policy again and save it - do you get any warnings?
Please give a full policy listing if you can or screenshots of the attributes and snapshot options

Authorised Symantec Consultant

Don't forget to "Mark as Solution" if someones advice has solved your issue - and please bring back the Thumbs Up!!.

Netbackup Admin Guy's picture

In the policy make sure the transfer type is configured as san and not try san then nbd.  This will insure only san transfer type is possible. Try backing up again and see what error occurs.  This time you will niow it is atleast trying the san transfer type only. 

I noticed in your previous post you stated, " the datastore LUNs are presented to the media server(VMware Backup Host)".  You must also make sure the ESX host is in the same SAN zone as your VMware backup host (media server).  This allows the hba card on the ESX host to communicate with the VMware backup host that is hosting the specific VM to be backed up.

Hope this helps.

Shay Xie's picture

Any update to this issue ?

I am having same issue:

1. netbackup verion 

2. datastores in FC SAN used by ESXs are visiable to the Vmware backup host, which is also a windows netbackup media server.

3.transfer type is configured as san  only.

4. the jobs finised successfuly. but when check the details and found the transfer mode is LAN.

which is wired. Becuase I did not setup to "try san then nbd". if it can not get to SAN mode, I wish it could fail but not goes to LAN mode automaitcally....

can anybody give more input ?



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captain jack sparrow's picture

Hi Shay

You could say it's shortcoming for NBU to show incorrect transport type. However it changes to FT only if you use SAN client with FT media server

It would not show SAN only if you use SAN media server to backup vmware or any other sort backups

 Cheers !!!