BackupExec 2014 to disk very slow

[GTeley]

Brand new BackupExec 2014 SBS edition on Windows Server SBS 2011.

High performance HP Proliant Server with SAS RAID50 volume with 2Gb battery backed cache.

Backup to Disk over 1Gb iSCSI connected network storage (14Tb) is very slow.

Bandwidth usage varies highly from 0% to max 50%

Because of this, backup duration is almost exceeding 1 day.

We are able to increase bandwidth usage to 100% by copying a large file to the same disk store while backup is running.

Network performance therefor is no issue. Disk fragmentation neither.

For backing up a second SQL server, we created a separate 2Gb LAN Team. Data transport from SQL server to media server is via this LAN Team.

Calculated max throughput would be (90% usage of 1Gb = 90Mb/s) = 5.4Gb/min. Achieved throughput = 1.2Gb/min

Software compression has been tested as an option but did not improve throughput.

[GTeley]

Forgot to add: AntiVirus has been disabled temporary to check impact on backup performance.

No measurable difference.

[GTeley]

It looks like it's getting worse. Backup throughput now is down to a crawling 21Mb/min.
Some input from Symantec would be appreciated!

[CraigV]

...have you done the following:

1. Made sure the NICs on the server and the storage are hard-coded to the maximum speed of the switch ports, ie. 1GB FULL?

2. Have you tried to enable jumbo frames to see what the performance boost is, bearing in mind it might hamper performance elsewhere?

Thanks!

[GTeley]

Yes, we did.

We also connected the iSCSI storage device back-to-back with the server.
As said before, it was no problem filling up the available bandwidth on the iSCSI connection by copying files over the link. BackupExec just doesn't seem to produce enough data to fill it up. 
 

[CraigV]

...if this is normal B2D, are the sizes of the B2D still set to 4GB? Have you tried to increase the size of the B2D files that are generated, bearing in mind that the larger the size the more data is lost if a file corrupts.

Thanks!