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Understanding spoold memory usage in NetBackup 7.6.x and NetBackup Appliance 2.6.x

Article: 100014654
Last Published: 2015-02-18
Ratings: 2 0
Product(s): NetBackup

Problem

NetBackup uses fingerprints to identify the file segments in the backup data.  NetBackup writes only unique data segments to a Media Server Deduplication Pool. If a segment already is in storage, NetBackup does not store it again. The storage server maintains an index cache of the fingerprints in RAM. For each backup job, a client requests a list of the fingerprints from its last backup from the server.  The NetBackup Deduplication Engine (spoold) loads a percentage of the fingerprints into the cache at startup. After startup, the Engine loads the remaining fingerprints.  By default the maximum amount of memory that spoold cache will use is 75% of your system memory.

Solution

In the event spoold is using too much memory, this behavior can be limited by editing the /<Dediplication_Path>/etc/puredisk/contentrouter.cfg and change the MaxCacheSize value from 75% to acceptable value.

Cache Usage can be found in the spoold logs:

# grep "Cache Usage" spoold.log*

Here is an example of the output:

Cache Usage              : 70248.00 MB, 2301789385 nodes, 61955 free, 2301789385 replaceable

Notice that spoold in the above example is using 68.6GB of RAM, and it has loaded 2.3 billion SOs into memory.

 

 

 

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