How to improve VMware backup performance for Backup Exec 2010 R3, 2012, 2014 and 15

Problem

Hotfix 176937 for Backup Exec 2010 R3 improved the performance of VMWare related backup jobs and the same is included in Backup Exec 2012, 2014 and 15. The best improvement gain is usually seen with backups using SAN transport type over backups using NBD backup type.  It will be a better impact with NBD type backup if the network is 10GB end to end. With this improvement there are 8 registry keys that can be modified towards getting optimal performance.   

Registry Keys and Location:
HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Backup Exec For Windows\Backup Exec\Engine\VMware Agent

Values                                   Default                                                                                                            

                                                         Hex         (dec)                
"Enable Buffered Reads"    =dword:00000001 (1)      
"Number of Read Buffers"  =dword:00000004 (4)     
"Size of Read Buffers"        =dword:00000400 (1024)      
"Enable Buffered Writes"    =dword:00000001 (1)      
"Number of Write Buffers"  =dword:00000004 (4)      
"Size of Write Buffers"        =dword:00000400 (1024)
"Write Thread Priority"       =dword:00000000 (0)       
"Read Thread Priority"       =dword:00000000 (0)   

  

Values                                   Recommended - 1GB NBD

                                                        Hex          (Dec)     
"Enable Buffered Reads"    =dword:00000001 (1)
"Number of Read Buffers"  =dword:0000000a (10)
"Size of Read Buffers"        =dword:00001000 (4096)
"Enable Buffered Writes"    =dword:00000001 (1)
"Number of Write Buffers"  =dword:0000000a (10)
"Size of Write Buffers"        =dword:00001000 (4096)
"Write Thread Priority"        =dword:00000001 (1)
"Read Thread Priority"        =dword:00000001 (1)

 

Values                                  Recommended - SAN/10GB NBD                

                                                         Hex         (Dec)             
"Enable Buffered Reads"    =dword:00000001 (1)
"Number of Read Buffers"  =dword:00000010 (16)     
"Size of Read Buffers"        =dword:00002000 (8192) 
"Enable Buffered Writes"    =dword:00000001 (1)      
"Number of Write Buffers"  =dword:00000010 (16)    
"Size of Write Buffers"        =dword:00002000 (8192)  
"Write Thread Priority"       =dword:00000001 (1)
"Read Thread Priority"       =dword:00000001 (1)


 

Note: The perfomance improvements are still limited to resource usage (local to the media server, on backup target and on the transport layer) at the time of the backups!

Solution

The following registry keys can be modified to improve performance based on the configuration and setup of the media server.  If the Media server has 8 CPU's and 12GB of memory then these values might be increased to see optimal performance.  If the Media server has 2 CPU's and 4GB of memory then these values might need to be decreased to see optimal performance. 

"Number of Read Buffers" and "Number of Write Buffers" can be increase to allow for additional buffers during the backup.  The default value is 4 and can be increased or decreased by increments of 2. 

"Size of Read Buffers" and "Size of Write Buffers" can be increased to allow for a larger buffer during the backup.  The default value is Hexadecimal 400 and can be increased or decreased by increments of 200. 

"Write Thread Priority" and "Read Thread Priority" Values are "0" normal, "1" above normal and "2" highest. Would not recommend to use any higher value than "1"!

 

 

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