Am 17.03.2014 03:55, schrieb Ming Lei:
On Mon, Mar 17, 2014 at 7:16 AM, Matthew Eaton
Tested on my system and saw no difference in performance. Direct io
will bypass the page cache so the only thing that comes to mind would
Looks I miss the '--direct=1' parameter, :-(
be an on-device cache, though, I would think the difference in
performance would be more dramatic if that were the case.
Another possible cause might be related with storage for the
big file. If the file is stored in lot of fragments of the disk, accessing
the whole file might become slower than just the first 10M, but not
sure if there is so big difference(30%).
Direct io
will bypass the page cache so the only thing that comes to mind would
be an on-device cache, though, I would think the difference in
performance would be more dramatic if that were the case.
This could be possible - I'm not so sure how to check that...
My setup is the following:
RHEL6.5 as virtual machine via VMWare - the storage is a Dell Equallogic
Storage connected via ISCSI to the host. These tests are not made via NFS.
I just wanted to make some tests before taking it all in production.
Thank you all for your answers!
Josef
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