On 10/26/2014 09:26 AM, Brian Foster wrote: > On Sat, Oct 25, 2014 at 04:26:54PM -0500, Stan Hoeppner wrote: >> On 10/25/2014 01:56 PM, Richard Scobie wrote: >>> Stan Hoeppner said: >>> >>>> How can I disable or change the filestreams behavior so all files go >>>> into the one AG for the single directory test? >>> >>> Hi Stan, >>> >>> Instead of mounting with -o filestreams, would using the chattr flag >>> instead help? >>> >>> See >>> http://xfs.org/docs/xfsdocs-xml-dev/XFS_User_Guide/tmp/en-US/html/ch06s16.html >> >> That won't help. That turns it on (if it's not enabled by default these >> days). I need to turn off the behavior I'm seeing, whether it's due to >> the filestreams allocator or default inode64. Then again it may not be >> possible to turn it off... >> >> Anyone have other ideas on how to accomplish my goal? Parallel writes >> to a single AG on the outer platter edge vs the same to all AGs across >> the entire platter? I'm simply trying to demonstrate the differences in >> aggregate bandwidth due to the extra seek latency of all AGs case. >> > > What about just preallocating the files? Obviously this removes block > allocation contention from your experiment, but it's not clear if that's > relevant to your test. If I create a smaller, but analogous fs to yours, > I seem to get this behavior from just doing an fallocate of each file in > advance. > > E.g., Create directory 0, fallocate 44 files all of which end up in AG > 0. Create directory 1, fallocate 44 files which end up in AG 1, etc. > From there you can do direct I/O overwrites to 44 files across each AG > or 44 files in any single AG. I figured preallocating would get me what I want but I've never used fallocate, nor dd into fallocated files. Is there anything special required here with dd, or can I simply specify the filename to dd, and make sure bs + count doesn't go beyond EOF? Thanks, Stan _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
