Recently, my NetBackup 8.1 (installed on Windows Server 2012 R2) suddenly runs at very slow speed (~40% less than its optimal speed).
After some troubleshootings, I discovered that if I downgraded it to 1Gbps from 10Gbps (simply swapping the transceiver of 10Gbps SFP+ with 1Gbps SFP, refer pic below), the speed recovered back to its optimal speed.
And swapping the transceivers is the ONLY thing I do. Any idea?
I would have asked network folks to check the port settings with the 1 Gbps and 10 Gbps SFP and compare these. maybe there is being changed anything. Also please see from host side for duplex/speed....
Bad network cable or SFP+. Try cleaning fiber optics first with a approve cleaning kit.
By downgrading to 1Gps, the numbers of bad transmissions will be reduced, since 1Gps is less sensitive to bad fiber optics than 10Gps. You should ask a network admin to look at the issue.
Curious so asking, Do you have additional or another interface attached to the Windows NetBackup server?
I have experienced slowness when I enabled a additional interface (private vlan) on the NetBackup server. It was back to normal when I disabled the second interface. Both were 10g though.