Cache is the memory that is installed in a RAID controller and is used as a data buffer for the RAID controller
to read and write data to the HDD units. Cache is used as a work area for parity generation processing.
Write Through
When write processing is requested from software such as OS, data is written to both the cache and the HDD on the RAID controller in Write Through mode. Since software advances to the next processing after completion of HDD write processing, in general, the access performance deteriorates due to Write Back. However, since the write request from the software reflects in the HDD immediately, the advantage of this mode is the low risk of losing data at the occurrence of an unexpected accident such as a temporary power failure. |