Hi folks, Is there a technical description of how the DistributedMapCacheServer (DMCS) persistence works? I've noticed the following on our cluster:
- I have the DMCS configured on port 4557 as FIFO with max 100,000 entries, and have specified a persistence directory - I am using DetectDuplicate with the DMCS, and the individual key length is 80 bytes, with a Description length of 1 byte. By my count, this should result in a pure data size of 7.7MB. - I notice that the snapshot file in the persistence directory appears to continue growing past the 100,000 limit, though this may be expected depending on the implementation. Since I know that the key will contain "json" in it, I can run the following command to count the number of possible keys in the snapshot file (though I'm not sure if this is a good way of measuring how many keys are actually cached): grep -oa json snapshot | wc -l - When the snapshot file reaches around 3GB, the DMCS has a hard time staying up, and frequently becomes unreachable (netstat -tulpn | grep 4557 shows nothing). At this point, in order to restore functionality I delete the persistence directory and let it start over. So my main questions are: - How are the snapshot and partition files structured, and how can I estimate how many keys are actually cached at a given time? - Is the described behavior indicative of the cache exceeding the configured max number of keys? Thanks, Joe -- I know what it is to be in need, and I know what it is to have plenty. I have learned the secret of being content in any and every situation, whether well fed or hungry, whether living in plenty or in want. I can do all this through him who gives me strength. *-Philippians 4:12-13*
