eventually, I fix the problem by changing the storage unit from OpenStorage disk device to an advanced disk device.
When the backup runs it has to effectively snapshot each database
Even though they are small you may be pushing the system to do 20 at a time
It is a little like VMware backups where you can often do 200 VM's faster by doing them 1 at a time than you can trying to do 6 at a time
So try changing the BATCHSIZE so see what difference it makes - it is set to 20 at the moment so try 10 and then 5 and then 30 and compare each setting to see the overall difference (if any) - do this until the optimum setting is found
Also bear in mind that you are also compressing 20 at a time - this normally speeds things up but maybe again at 20 it is just too much - so as a second test you could also try the different batch sizes with and without compression
All the other usual stuff also applies in relation to network and data buffers used but during testing only change one thing at a time to see the effect that produces
Hope this helps
