how to increase NDMP backup throughput

Question

Hello all, IHAC who complains about NDMP performance (data throughput) while saving data from NAS Storage (Netapp) to VTL tape drives (FC-) attached to storage system. As per customer it is not possible to get more than 150 MB/s for NDMP traffic (also using multiple NDMP streams). Neither storage nor VTL support has identified performance issue on their devices. As per NDMP probe output from storage system the mover.recordSize for active NDMP sessions is set to 61440 B. The assumption is that increasing the block size (mover.recordSize) let say to 262144 B would provide also greater throughput. The mover.recordSize on Netapp storage can be set with NDMP variable MOVER_SET_RECORD_SIZE. I did not find out in Networker documentation how to adjust MOVER_SET_RECORD_SIZE in NDMP client resource. Is there way to configure MOVER_SET_RECORD_SIZE for NDMP Client with Networker? Thanks.

gnworker · Accepted Answer

As per NW admin guide the vendor specific NDMP variable NDMP_AUTO_BLOCK_SIZE=Y can be used in conjunction with 'Device block size' attribute of NDMP volume.

gnworker · Answer

BTW, as per Netapp TR-3815 it is possible to configure tape block size in Netbackup SW:

"To get maximum speed of Tape drives, Tape block size tuning is required in NetBackup.

For NetApp storage, a maximum tape record size of 256K could be set. The NDMP dump default value is 63k and
SMTape default record size is 240k.
Changing this parameter increases the throughput if we use latest tape drives.
Create a file called "SIZE_DATA_BUFFERS_NDMP" and set the block size as 262144 under "(NetBackup application
installed directory)\NetBackup\db\config\."

So, I would expect this feature is also available in Networker.

Thanks.

gnworker · Answer

NDMP_TAPE_BLOCK_SIZE environment variable is mentioned in following KB: https://emc--c.na5.visual.force.com/apex/KB_ETA?id=kA37000000000XJ

NetWorker

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