Mikle, A pure data is a size of(keyByte+ValueBytes), as I can see you have Key=int and Value=String(1024) 4+1024 bytes this is your pure data size which will be stored in the cache (of course Ignite has overhead for save data ~45 bytes )
In internal Ignite has a structure named "FreeList" for tracking free space, the in-memory region has only one FreeList for the region, the persistence region has FreeList per partition in the cache, this means persistence case have move overhead for internal structure. This structure has 256 buckets in each bucket we have a page, so this means we may have 256*pageSize(4kb) - 1mb overhead. As default value cache has 1024 partition, therefore we may have 1GB overhead if we putting data in each partition repeatedly. in custody, persistence mode may have more overhead for work with data, it related to the internal structure. As a check, you can persistence create a cache with 1 partition and the result will be the same as in-memory. -- Sent from: http://apache-ignite-users.70518.x6.nabble.com/
