Hi, in /proc/fs/lustre/obdfilter/*/brw_stats I found that the disk I/O is done in 512K pieces. Following the Lustre manual I changed /sys/block/DEVICE/queue/max_sectors_kb to 1024 but the I/O sizes in Lustre didn''t change. Is there any place in Lustre where I can enforce 1MB I/Os? What else can I do? My RAID is connected through an mpt fusion driver and I cannot find any place where the I/O size is limited to 512KB. In fact, without Lustre I am able to write with larger I/Os, so I suspect it''s not the driver''s fault... Regards, Erich