>
> 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.
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