Return
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Title
Slow read speed from DR appliance out to NetBackup media server via OST to write to tape. -
Description
Slow read speed from DR appliance out to NetBackup media server via OST to write to tape.
For example, seeing a max read speed of about 100 MB/s over 10 Gbps ethernet connections.
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Cause
NetBackup NUMBER_DATA_BUFFERS tuning parameter set too low. -
Resolution
A single stream read-out from DR can get 100-120 MB/s on CIFS, but should get to ~300 MB/s single stream readout using OST.On multiple stream readout, it should go to 400 MB/s on both CIFS and OST.In NetBackup, there is a buffer tuning parameter that may need to be increased. In an example use case scenario, after increasing the NetBackup tuning parameter NUMBER_DATA_BUFFERS to 256 up from the default of 32, single stream speeds went from 100 MB/s to full LTO7 speeds (~300 MB/s).Please see the following link for more details on changing the NetBackup NUMBER_DATA_BUFFERS parameter:https://www.veritas.com/support/en_US/article.100008276