On Sun, Jan 24, 2010 at 07:22:08PM -0500, nixlists wrote: > On Sun, Jan 24, 2010 at 12:22 PM, Jonathan Thornburg > <jth...@astro.indiana.edu> wrote: > > In message <http://marc.info/?l=openbsd-misc&m=126356588306613&w=1>, > > Marco Peereboom <slash () peereboom ! us> wrote > >> You can do everything right all day long in software but hardware does > >> what it does and claiming that a piece of software is crash proof is > >> naive at best. > > > > Hmm. Our rename(2) man page currently says: > > > > rename() guarantees that if _to_ already exists, an instance of _to_ > > will always exist, even if the system should crash in the middle of > > the operation. > > > > Should this perhaps be changed to read something like this? > > > > rename() tries to guarantee that if _to_ already exists, an instance > > of _to_ will always exist, even if the system should crash in the > > middle of the operation. However, in some cases the hardware may > > not provide the proper support, causing the guarantee to fail. > > > > Or do we (as a general policy) take this sort of escape clause taken to > > be implied to knowledgable readers, and thus need not be explicitly stated? > > It's of course implied that hardware and FFS work as they should for > the guarantee to work, but...
Virtually all PATA & SATA disks have write back cache enabled. Some FC, SCSI and SAS do too. > No one seems to want or be able to point out any particular hardware > that rename() (and subsequently FFS and MTAs) fail on! Virtually all PATA & SATA disks have write back cache enabled. Some FC, SCSI and SAS do too. > When configured as documented - no controller write-back cache (maybe > with a battery back-up, but batteries fail too), no drive write-back > cache, no async mounts, no known buggy stuff. Virtually all PATA & SATA disks have write back cache enabled. Some FC, SCSI and SAS do too. > Which hardware??? Could someone at least point out one example of such > hardware? Virtually all PATA & SATA disks have write back cache enabled. Some FC, SCSI and SAS do too. > I, and, I am sure many other people who run mail servers would love to know. Hope you now know that virtually all PATA & SATA have WB cache enabled.
