On Wed, May 19, 2010 at 02:29:24PM -0700, Don wrote: > "Since it ignores Cache Flush command and it doesn't have any > persistant buffer storage, disabling the write cache is the best you > can do." > > This actually brings up another question I had: What is the risk, > beyond a few seconds of lost writes, if I lose power, there is no > capacitor and the cache is not disabled?
You can lose all writes from the last committed transaction (i.e., the one before the currently open transaction). (You also lose writes from the currently open transaction, but that's unavoidable in any system.) Nowadays the system will let you know at boot time that the last transaction was not committed properly and you'll have a chance to go back to the previous transaction. For me, getting much-better-than-disk performance out of an SSD with cache disabled is enough to make that SSD worthwhile, provided the price is right of course. Nico -- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
