SUMMARY
Steps to debug poor Hot Backup Copy (Replication) performance.
ISSUE
Replication is slow, but, pipe speed over the VPN conduit seems to be good. (VPN performance can be tested using iPerf or by copying large files through the conduit)
After basic analysis no errors are found in logs, and database performance on the source and target units does not appear impacted, yet replication is still slow.
For more information on Hot Backup Copy (Replication) issues see Unitrends KB 5030 - Hot Backup Copy (Replication) Overview, Setup and Error Troubleshooting
RESOLUTION
Connect to the appliance via SSH and open /usr/bp/bpinit/master.ini
vi /usr/bp/bpinit/master.ini
In the [Debugging] section on the source unit:
- Set the VCD logging level to either 0 or 1 by adding or editing the following line:
vcd=0
If the VCD log level is set higher than 1, replication performance will suffer, dramatically.
In the [Debugging] section on the target unit:
- Set the VaultServer logging level to either 0 or 1 by adding or editing the following line:
vaultServer=0
If the vaultServer log level is set higher than 1, replication performance will suffer, dramatically.
In the [Replciation] section (on the source unit):
-
Ensure localBlockElimination=True or the localBlockElimination (LBE) line is not present at all. LBE set to false will cause unnecessary overhead on synthetic full and differential processing, and cause long replication windows.
localBlockElimination=True
- if the VCD log level was 2 or higher, it is practice to set ThreaddedSendBlocks=0 in the [replication] section of the master.ini. This needs to be removed. If you find the following line in the [Replication] section of the source master.ini, delete it:
ThreadedSendBlocks=0
Important: Never set the VCD log level above 1 unless ThreadedSendBlocks=0 is set.
Once the VCD log level is reduced back to 0 or 1 Remove the line item for ThreadedSendBlocks from master.ini.