NetBackup Appliance 5220 Slow Rehydration to tape
I know there have been lots of comments surrounding slow rehydration to tape from the appliances but mine is just to slow and the appliance can't keep up with the demand.
Master server = Windows 2008 R2 SP1 NetBackup 220.127.116.11
Appliances 5220 = NetBackup 18.104.22.168 (patch 2.5)
Tape drives linked to appliance at 4GB over fibre ibm 3592 drives capable of over 100mb a second native without compression over 200mb a second when compressing.
We have an SLP to backup our Exchange servers to a 5220 appliance then replicated to another 5220 on a different site but same netbackup domain and then rehydrate to tape from there. We have 12 tape drives avalaible but currently the storage unit is set to allow 4 concurrent write drives for the duplication to tape. The exchange servers are the passive nodes and we are using client side dedupe on them as its faster than using the appliance dedupe as there are 6 servers totaling in about 13TB of data.
All buffers are set to appliance defaults at 256kb (262144) and using 30 buffers. we currently use this on our master server catalog backup and get over 120MBps
Currently tape speeds on rehydration are around 15 -25MBps topping out across all 4 streams at 75-85MBps. This speed is appauling when you have 13TB a night to get to tape.
I have tried running a single stream to tape and it still can only produce around 50-60MBps
Has anyone had any luck improving this?