GraySplatter
Junior Member
We have a number of DL360s and 380s all with the HP SmartArray controllers w/ BBU. And on every single one I see this behavior:
Appending to a single, synchronous (O_SYNC) file, the call to write() returns in ~300us. If I have two threads appending to their own individual synchronous files, the call to write() returns in closer to 2ms. Write sizes range from 1kb - 20kb, much smaller than the stripe size. We have write-back caching enabled with 75% of the 512MB cache dedicated to write cache. So why do the writes seem to behave as if it were write-through?
I suspect we have something misconfigured or have failed to enable something somewhere. My SA insists that write-back is enabled and I'm inclined to believe him.
Anybody have any experience with this?
Thanks!
Appending to a single, synchronous (O_SYNC) file, the call to write() returns in ~300us. If I have two threads appending to their own individual synchronous files, the call to write() returns in closer to 2ms. Write sizes range from 1kb - 20kb, much smaller than the stripe size. We have write-back caching enabled with 75% of the 512MB cache dedicated to write cache. So why do the writes seem to behave as if it were write-through?
I suspect we have something misconfigured or have failed to enable something somewhere. My SA insists that write-back is enabled and I'm inclined to believe him.
Anybody have any experience with this?
Thanks!
