After the Commvault refresh/reconfiguration which was concluded some months back, we had some issues backing up to tape which we finally understood was related to the tape drives we were using then.
We have resolved the issue with the drives but we are still having copy to tape running at a very low speed (As low as 13GB/hr).
Kindly assist us with below.
We have sister companies running this same Commvault and we want to know how their setup is different from ours that make them better.
We need to review our architecture to be sure the copy to disk and copy to tape can happen at the same time from the primary source.
The difference in storage in terms of I/O and disk rpm from what we have here and that of our sister companies.
Their major point, is, is it possible to have the primary copy to disk running and have the copy to tape run at the same time?
Is it possible? And what’s the implication?
If you mean, can you copy data from running backups before they complete - the answer is yes. You enable it on the secondary copy properties I believe. (Copy Properties / Copy Policy) - there are caveats that the documentation notes below:
If selected, when an auxiliary copy job with the Use Scalable Resource Allocation option enabled is performed during a backup job, the data available on the primary copy is picked for copy by the running auxiliary copy job. This option causes the auxiliary copy operation to create the secondary copy faster. This option saves time for the auxiliary copy operation, especially when the backups running are huge.
There’s a tool we have (mentioned in this thread here) that can give you the breakdopwn of each portion of the job and show you where the bottleneck is.
Their major point, is, is it possible to have the primary copy to disk running and have the copy to tape run at the same time?
Is it possible? And what’s the implication?
If you mean, can you copy data from running backups before they complete - the answer is yes. You enable it on the secondary copy properties I believe. (Copy Properties / Copy Policy) - there are caveats that the documentation notes below:
If selected, when an auxiliary copy job with the Use Scalable Resource Allocation option enabled is performed during a backup job, the data available on the primary copy is picked for copy by the running auxiliary copy job. This option causes the auxiliary copy operation to create the secondary copy faster. This option saves time for the auxiliary copy operation, especially when the backups running are huge.
---------------------------------- | READS FROM THE SOURCE ARE SLOW | ---------------------------------- - Make sure maximum reader streams are selected for AuxCopy. - Run CvDiskPerf on the source path to ensure the disk(s) are optimized for random I/O. - Ensure Distribute data evenly for offline reads are selected from the storage policy properties. - Review and increase the DataMoverLookAheadLinkReaderSlots to increase the read ahead factor (max value is 128). Suggested values 32, 64, 128. - If Auxcopy is copying synthetic fulls, ensure that the agent that ran synthetic full supports multiple streams to maximize AuxCopy read performance.
@Mubaraq , regarding the stream perfornance, what is the expected throughput? The read speeds are the slowest as you mentioned, but they all that much slower than write and network transfer.
They expect like a 200GB/Hr but i am going to propose running auxiliary jobs 4 hours to break the read operation and network transfers into chunks, instead of having one schedule per day.
Is 200 GB/hr reasonable for the hardware (read, network, and write)? In any throughput question, a valid expectation is a must….too often someone expects something that the setup will never delivery
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