maxPersistentCacheSize
Maximum device storage size in bytes used for all persistent caches.
Persistent cache for each AccountDescriptor is stored in separate database.
When maxPersistentCacheSize is exceeded a Sync Client first remove old (looking at dataModified of the database file) databases first. In the last database, least recently used records are removed (if necessary) in order to fit into the size limit.
Default value is 100Mb. null value is INFINITE size.