В Mon, 03 Jun 2013 11:14:07 +0200 Roger Oberholtzer <roger@opq.se> пишет:
I am using XFS on a 12.1 system. The system records jpeg data to large files in real time. We have used XFS for this for a while since it has as a listed feature that it is well suited to writing streaming media data. We have used this for quite a while on openSUSE 11.2.
We have developed a new version of this system that collects more data. What I have found is that the jpeg data is typically written at the speed I expect. Every once in a while, the write takes 100x longer. Instead of the expected 80 msecs or so to do the compress and write, it takes, say, 4 or 5 seconds. I have looked in all the usual suspect places, and nothing seems to point at anything. For one test, I wrote to /dev/null instead of the real file, The delays do not happen. They do seem to be related to actually writing to the physical disk.
I expect some delay occasionally when disks are physically flushed. There is buffering in our application to allow this. But 5 seconds is simply wrong.
BTW this may explain one possible cause: http://serverfault.com/questions/126413/limit-linux-background-flush-dirty-p... -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org