Garbage Collection is not running (4047330)

Date: Sept 2010

Affected Product & Version :  NSD all versions

Affected Module & Version : N/A

OS Version - any


Symptoms: Garbage Collection never seems to run.


Cause: Something is blocking Garbage Collection.

Run the following command;

(Windows) <SmartDisk_Install_path>\foundation\bin\smartdisk config --show
(Linux) <SmartDisk_Install_path>/foundation/bin/smartdisk.sh config --show

Looking at the output, check the following conditions;

1) Under the heading [Deduplication:Enable] is 'Value=FALSE' ?
Deduplication is not enabled. Garbage Collection cleans up expired data in the dedupe store, if you don't use deduplication, then there is no need to run Garbage Collection.

2) Under the heading [Deduplication:GC] note the setting for 'Window'.
If the system time is outside the window, Garbage Collection cannot start.
It is possible to change the window with the following command;

(Windows) <SmartDisk_Install_path>\foundation\bin\smartdisk config --gc-window <window_specification>
(Linux) <SmartDisk_Install_path>;/foundation/bin/smartdisk.sh config --gc-window <window_specification>;
See the SmartDisk Administrator Guide for full window specification.

3) Check for deduplication activity. Run the following command.

(Windows) <SmartDisk_Install_path>\foundation\bin\smartdisk stats
(Linux) <SmartDisk_Install_path>/foundation/bin/smartdisk.sh stats

Under the heading [SmartDisk:Deduplication Scheduler] check the entry Elements.Deduplicating. If this is non zero, there are deduplications running.
Duplications must be idle for Garbage Collection to run.

4) Have any backups expired ?
Garbage Collection is triggered by expiration of data.


Explanation:

For GC to run, it needs to be triggered by an expiry of deduplicated data, the GC window must be open and there must not be any deduplications running.