@Miron Cuperman, I see what you are saying. However, if an application wants to
ensure that at flush time the data finds its way on the hard disk rather than
the disk cache then the disk caches should be turned off (as you mentioned in
your description, this gives you the correct performance). Also the only other
method is to have a power backed up cache.
Please refer to: http://xfs.org/index.php/XFS_FAQ for more details.
As, I mentioned before, you are seeing the speed difference in
data=journalled mode probably because of more data that has to be
written. This mode does not ensure that your data finds its way onto the
harddisk instead of the disk cache. I believe that a filesystem would
not ensure that data finds its way straight to the disk rather than the
cache. This same option can be obtained by disabling the disk cache (and
hence not needed to be implemented in the FS) So, if the data base
application _MUST_ have the data on disk, it should simply turn off the
disk cache (and get a performance hit) or have power backed up cache.
I am marking this bug as invalid, as this behavior of data going into
the cache when disk cache is enabled, is expected behavior for ext[3-4]
** Changed in: linux (Ubuntu)
Status: Triaged => Invalid
--
ext3/4 fsyncdata does not flush disk cache
https://bugs.launchpad.net/bugs/504632
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
