IT33030: VSNAP OFFLOAD THROTTLING DOES NOT WORK AS EXPECTED

APAR status

• Closed as program error.

Error description

• When offload throttling is enabled, in the site settings, the
  throttling limit is not honored correctly. In cases where the
  network connectivity is limited, this can cause other
  connectivity problems as Plus attempts to take up all available
  bandwidth.
  
  The vSnap logs will show throttling is properly
  configured:
  
  vsnap.repld Monitor: Checking status of 1 active
  sessions
  vsnap.common.mvr Rate is being throttled to 26214400.0
  B/s
  
  This does not affect replication.
  
  Keywords: TS003605271
  offload off-load s3
  

Local fix

• Run the following commands on the vSnap server(s) performing
  offload.
  # It's safe to run this command even if it was not
  previously set.
  
  vsnap system pref clear --name
  cloudOffloadRate
  
  # Change max parallel copy operations to 1.
  Default is 5
  vsnap system pref set --name cloudMaxStreams
  --value 1
  
  # Change max parallel upload threads per operation
  to 1. Default is 16.
  vsnap system pref set --name
  cloudOffloadThreads --value 1
  
  
  
  Monitor the performance.
  These values can be increased if needed.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * IBM Spectrum Protect Plus level 10.1.5 and 10.1.6.           *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply fixing level when available. This problem is currently *
  * projected to be fixed in IBM Spectrum Protect Plus level     *
  * 10.1.6.ifix2 and 10.1.7. Note that this is subject to change *
  * at the discretion of IBM.                                    *
  ****************************************************************
  

Problem conclusion

• When copying data to object storage, data from the disk-based
  vSnap pool is first copied to a cache area under /opt/vsnap-data
  and then uploaded to the target server. When a bandwidth
  throttle is defined, the copy process throttled the rate at
  which the data is copied to the cache area but did not throttle
  the actual uploads of the aggregated files. As a result, the
  upload process used more bandwidth than the configured throttle.
  
  The problem has been resolved by improving the way throttles are
  implemented on the vSnap. The new implementation uses network
  traffic throttling at the IP layer to ensure that outgoing
  network traffic to the cloud endpoint is correctly throttled.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  SP PLUS

• Fixed component ID

  5737SPLUS

Applicable component levels