On Tue, 15 Nov 2016, Simon Slavin wrote:
Modern storage subsystems (hard disk or SSD) intended for use in a normal user computer always lie to the OS about flushing to disk. The apparent increase in speed from doing this is so big that every manufacturer has to do it, or risk having every review harp on about how slow their computer performs in real life tasks. There is no way to get these things to be honest. Because not one person in ten thousand cares. Most people are more interested in how fast they can launch Microsoft Word.
I don't think that things are as bad as you say. Some modern filesystems (e.g. zfs) depend on hardware cache flush to work yet there has not been a rash of corrupted filesystems. Many people use these filesystems on non-enterprise hardware.
There are some devices which do fail to flush their cache or write data properly. Some SSDs likely re-write data while in use or idle due to wear leveling in a way which causes a possibility of loss.
Enterprise disks are more tolerant of vibration, are specified to have fewer uncorrected bit errors, and try for a bounded time to recover bad sectors.
MacOS's target market is not storage. The useful mass storage offerings for hardware running MacOS is rather limited.
Operating systems where fsync() or fdatasync() do not truely commit data to hardware are broken.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
