Re: [Jfs-discussion] benchmark results

jim owens
2009-12-26T16:00:21Z

Christian Kujau wrote:

> I was using "sync" to make sure that the data "should" be on the disks

Good, but not good enough for many tests... info sync

CONFORMING TO
POSIX.2

NOTES
On Linux, sync is only guaranteed to schedule the dirty blocks for
writing; it can actually take a short time before all the blocks are
finally written.

This is consistent with all the feels-like-unix OSes I have used.

And to make it even more random, the hardware (drive/controller)
write cache state needs to be accounted for, and what the filesystem
does if anything to try to ensure device-cache-to-media consistency.

That does not mean I'm saying the tests are invalid or not useful,
only that people need to evaluate "what do they really tell me".

jim