> > Can *someone* please name a single drive+firmware or > RAID > controller+firmware that ignores FLUSH CACHE / FLUSH > CACHE EXT > commands? Or worse, responds "ok" when the flush > hasn't occurred?
I think it would be a shorter list if one were to name the drives/controllers that actually implement a flush properly. > Everyone on this list seems to blame lying hardware > for ignoring > commands, but disks are relatively mature and I can't > believe that > major OEMs would qualify disks or other hardware that > willingly ignore > commands. It seems you have too much faith in major OEM's of storage, considering that 99.9% of the market is personal use, and for which a 2% throughput advantage over a competitor can make or break the profit margin on a device. Ignoring cache requests is guaranteed to get the best drive performance benchmarks regardless of what the software is driving the device. For example, it is virtually impossible to find a USB drive that honors cache sync (to do so would require that the device would stop completely until a fully synchronous USB transaction had made it to the device, the data had been written). Can you imagine how long a USB drive would sit on store shelves if it actually did do a proper cache sync? While USB is the extreme case; and it does get better the more expensive the drive, it is still far from a given that any particular device properly handles cache flushes. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
