4 ms·
Backups don't help if writes don't make it to disk in the order and manner expected by the application programmer. There's an emerging consensus that there are
by johnbender 10y ago
Backups don't help if writes don't make it to disk in the order and manner expected by the application programmer. There's an emerging consensus that there are crash protocol bugs lurking everywhere due to I/O scheduler reordering. For example this bug in gzip:
http://bugs.gnu.org/22768 http://bugs.gnu.org/22768
- EdiX 10y agoThis bug report is truly surreal. A filesystem could easily just write on disk directly skipping write buffers, the whole reason they don't is "because performance". In fact the "file system mathematically guaranteed to not lose data" is too slow to be used in practice and will implement fsync/fdatasync in the future to regain performance (and in the process it will stop being "mathematicall guaranteed not to lose data"). Clearly the solution is to add fsync/fdatasync calls to every single program so as to negate the performance gains of file system write buffers entirely. Clearly, the next step after that is for filesystem to start ignoring fsync/fdatasync entirely, because otherwise they would be too slow.