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Question on LRU memory management with partionedSync2Backup

I would like to understand what would happen to the primary and backup of a partition in this scenario:

3 machines, 4 gscs on each machine, each gsc is allocated 2 gb of memory.

If I deploy a partitionedsync2backup space with 6 partitions and 1 backup, some gscs will end up with 2 PUs and some will have 1 PU. If partition A's primary is in gsc 1 by itself, and partition A's backup is in gsc 2 along with partition B's backup, then partition A's primary and backup cannot possibly hold the same amount of data in memory (since gsc 2 is shared by two backup PUs). The question is, when LRU's memory management kicks in for partition A's primary, does it affect partition A's backup?

Thanks Sean

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asked 2009-05-28 16:38:34 -0500

sean.zhong gravatar image

updated 2013-08-08 09:52:00 -0500

jaissefsfex gravatar image
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Eviction is autonomic - each space evicts its data based on the max amount of objects and the JVM free memory.
When running in LRU mode it is recommended to have space per GSC. This will give you better control on the eviction.

We do have plans changing the way eviction works in such cases to replicate eviction operations - this will make sure both primary and backup will have identical data.

Still , let's not forget all the data is stored within the database , so no matter happens the space will load missing objects from the database.

Remember also that objects loaded into the primary as a result of cache miss (read operation) will not be replicated into the backup. This might be another change we will be doing in the future.

The parameter that controls if write operations are replicated to the backup when running in LRU with EDS is the EDS central data source property. With central mode write operations are not replicated. With non central data source mode write operations are replicated.


answered 2009-05-28 18:08:03 -0500

shay hassidim gravatar image
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Asked: 2009-05-28 16:38:34 -0500

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Last updated: May 28 '09