2.3.1 Cache types

EADS supports three types of caches, as explained below. You use the cache type that is appropriate to your operation methods.

Table 2‒1: Cache types and their characteristics
No.	Cache type	Data storage	Characteristics
1	Memory cache	Memory area	Data can be referenced and updated at high speed. Data loss might occur in the event of a failure because data is managed in memory.
2	Disk cache	Disk area	Data can be made persistent by using files. Data referencing and data updating create disk access overhead. A volume of data greater in size than the size of the physical memory can be stored. If redundant copies of data are created, data can be restored even when more EADS servers fail than there are data copies.
3	Two-way cache	Memory area and disk area	Data can be referenced at high speed. Data can be made persistent by using files. Data updating creates disk access overhead. If redundant copies of data are created, data can be restored even when more EADS servers fail than there are data copies.