Hello everyone!
Agent size volume E:\ 64 TB and used 50 TB it's backup failed with error "There was a problem with the VSS subsystem" and in event viewer error : VSS VolSnap Error 5 on agent. I'm not sure about memory on client or capacity for vss snapshot insufficient or any issue ?
Rapid Recovery 6.0.2
Client run on VMware ESXi : Windows 2012 R2 : Memmory 24 GB
Thank you,
Hi Keerati:
In plain English, "VSS VolSnap Error 5" means that there were insufficient resources allocated for the VSS snap job.
I assumed that you have used VSSAdmin to inspect the state of your VSS writers and they are OK. If there are some issues, please refer to the following KB for info as how to reset VSS writers without a reboot.
https://support.software.dell.com/appassure/kb/129774?cmpid=soc:appassure:communties:01
Once we took this out of the equation, there are a few possible causes for the error you have encountered.
The first that comes to mind is related to the size of your volume as the limitation of the Volsnap driver is 64TB (while the limitation of the NTFS file system is 256TB). If it is the case, slightly shrinking the volume may fix the issue.
Another possible issue may be related to the space taken by the VSS snapshots. There may be a few older VSS snapshots taking all the space allocated for VSS snapshots. There are two steps to fix this.
1. use diskshadow to delete any previous vss snapshot
2. make sure that there are no shadows enabled on the volume and that the shadows size limitations are removed
At last, there may be some memory management issues as well. You can monitor the memory variations in Performance monitor. I am hesitant to advise you trying the fix below as it may or may not address this issue and the outcome may be harmful. In case you would like to poke around, strictly for information purposes, the key is
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management
Add the following registry value:
Value name: PoolUsageMaximum
Data type: REG_DWORD
Radix: Decimal
Value data: 60
Setting the value at 60 informs the Memory Manager to start the trimming process at 60 percent of PagedPoolMax rather than the default setting of 80 percent. If a threshold of 60 percent is not enough to handle spikes in activity, reduce this setting to 50 percent or 40 percent.
Change the following registry value:
Value name: PagedPoolSize
Data type: REG_DWORD
Radix: Hex
Value data: 0xFFFFFFFF
Setting PagedPoolSize to 0xFFFFFFFF allocates the maximum paged pool in lieu of other resources to the computer.
Please note that I have added the "Registry usage disclaimer" as I consider the info above as interesting technical information but I would not use it in any production machine.
On the troubleshooting side, you can always attempt creating a snapshot and get some more insight as of the causes by using diskshadow. Please see the example below. As you see, the shadow is removed after its creation (the "end backup" command).
Hi Keerati:
In plain English, "VSS VolSnap Error 5" means that there were insufficient resources allocated for the VSS snap job.
I assumed that you have used VSSAdmin to inspect the state of your VSS writers and they are OK. If there are some issues, please refer to the following KB for info as how to reset VSS writers without a reboot.
https://support.software.dell.com/appassure/kb/129774?cmpid=soc:appassure:communties:01
Once we took this out of the equation, there are a few possible causes for the error you have encountered.
The first that comes to mind is related to the size of your volume as the limitation of the Volsnap driver is 64TB (while the limitation of the NTFS file system is 256TB). If it is the case, slightly shrinking the volume may fix the issue.
Another possible issue may be related to the space taken by the VSS snapshots. There may be a few older VSS snapshots taking all the space allocated for VSS snapshots. There are two steps to fix this.
1. use diskshadow to delete any previous vss snapshot
2. make sure that there are no shadows enabled on the volume and that the shadows size limitations are removed
At last, there may be some memory management issues as well. You can monitor the memory variations in Performance monitor. I am hesitant to advise you trying the fix below as it may or may not address this issue and the outcome may be harmful. In case you would like to poke around, strictly for information purposes, the key is
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management
Add the following registry value:
Value name: PoolUsageMaximum
Data type: REG_DWORD
Radix: Decimal
Value data: 60
Setting the value at 60 informs the Memory Manager to start the trimming process at 60 percent of PagedPoolMax rather than the default setting of 80 percent. If a threshold of 60 percent is not enough to handle spikes in activity, reduce this setting to 50 percent or 40 percent.
Change the following registry value:
Value name: PagedPoolSize
Data type: REG_DWORD
Radix: Hex
Value data: 0xFFFFFFFF
Setting PagedPoolSize to 0xFFFFFFFF allocates the maximum paged pool in lieu of other resources to the computer.
Please note that I have added the "Registry usage disclaimer" as I consider the info above as interesting technical information but I would not use it in any production machine.
On the troubleshooting side, you can always attempt creating a snapshot and get some more insight as of the causes by using diskshadow. Please see the example below. As you see, the shadow is removed after its creation (the "end backup" command).
