I found out from the Docs that, given 100% usage of disk cache by orientdb, it uses a maximum size of 70% for read cache and 30% for write cache (http://orientdb.com/docs/last/plocal-storage-disk-cache.html#interaction-between-read-and-write-caches).
Reading more about the read cache, it's divided by 3 queque: a1in, a1out and am which their respectively maximum sizes are 25%, 50% and 75% of the read cache size (http://orientdb.com/docs/last/plocal-storage-disk-cache.html#queue-sizes).
It is clear that, in stable condition with the read cache full, it needs more than 70% of disk cache for the read cache. How is this handled? Some space is took from the write cache or simply more space from the start is given to the read cache?
Also, I would like to be sure that:
- the "disk cache" involved is the RAM included with a common disk (HDD or SDD) and not the RAM of the machine;
- the default space of disk cache used by orientdb is 100%, as written in the first link (possible to change with storage.diskCache.bufferSize parameter)
Thanks everyone!