As a result the reduction write events can improve hard drive's data transfer thus improve write speed. To check whether write-back caching is enable on your hard drive use:
# hdparm -W /dev/sda /dev/sda: write-caching = 1 (on)
The write-back cache is enable by default on most hard drives. This technology is especially important for SSD ( Solid Sate Drives ) which are based on flash technology which has limited number of write/erase cycles. By transferring data first to volatile cache memory and write them in single batch, the write-back caching reduces life cycle of most of the SSD's.
Not all system's belong to the same "turn-on write-back caching" recommendation group as write-back caching caries a risk of data loss in the event such as power failure etc. In the event of power failure, data residing in the hard drive's cache do not get a chance to be stored and a lost. This fact is especially important for database system. In order to disable write-back caching set write-caching to 0:
# hdparm -W0 /dev/sda /dev/sda: setting drive write-caching to 0 (off) write-caching = 0 (off) # hdparm -W /dev/sda /dev/sda: write-caching = 0 (off)