https://community.hpe.com/t5/general/hard-disk-cache/m-p/4416385#M3900 On some arrays it is possible to turn on write-back caching at the disk drive level, but as you correctly said "disk drives do not have a battery". It is turned off by default because the vendor cannot make sure a customer's array is always running on a redundant or reliable power source (even UPSes can fail!). Sun, 10 May 2009 05:15:23 GMT Uwe Zessin 2009-05-10T05:15:23Z https://community.hpe.com/t5/general/hard-disk-cache/m-p/4416384#M3899 Hi,<BR /><BR />Probably this is a stupid question, but I have to ask :)<BR /><BR />When I read a hard disk specification there is *cache* size field. This cache at the HARD DISK is used only for reading, right? I wonder if it could be used for write caching a power loss could corrupt data and as far as I know hard disks does not have a battery, only disk controllers. <BR /><BR />This way I conclude that I can enable write caching only at the controller level because this can be battery backed and the cache field at hard disk specifications is for reading only.<BR /><BR />Am I correct?<BR /><BR />Thanks! Fri, 08 May 2009 19:46:54 GMT https://community.hpe.com/t5/general/hard-disk-cache/m-p/4416384#M3899 George Luiz 2009-05-08T19:46:54Z https://community.hpe.com/t5/general/hard-disk-cache/m-p/4416385#M3900 On some arrays it is possible to turn on write-back caching at the disk drive level, but as you correctly said "disk drives do not have a battery". It is turned off by default because the vendor cannot make sure a customer's array is always running on a redundant or reliable power source (even UPSes can fail!). Sun, 10 May 2009 05:15:23 GMT https://community.hpe.com/t5/general/hard-disk-cache/m-p/4416385#M3900 Uwe Zessin 2009-05-10T05:15:23Z