On Thu, 23 Jun 2005, Tom Lane wrote: > [ on the other point... ] > > Curt Sampson <[EMAIL PROTECTED]> writes: > > But is it really a problem? I somewhere got the impression that some > > drives, on power failure, will be able to keep going for long enough to > > write out the cache and park the heads anyway. If so, the drive is still > > guaranteeing the write. > > If the drives worked that way, we'd not be seeing any problem, but we do > see problems. Without having a whole lot of data to back it up, I would > think that keeping the platter spinning is no problem (sheer rotational > inertia) but seeking to a lot of new tracks to write randomly-positioned > dirty sectors would require significant energy that just ain't there > once the power drops. I seem to recall reading that the seek actuators > eat the largest share of power in a running drive...
I've seen discussion about disks behaving this way. There's no magic: they're battery backed. Thanks, Gavin ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
