Hi to all, I'm testing a storage (14x300GB) with different RAID levels, volume stripe sizes and different blocksizes and numjobs in fio ...but I've found a problem testing it with disks in RAID6 configuration. here is the command line I've used ----- fio --filename=/dev/dm-0 --direct=1 --group_reporting --rw=read --bs=1k --numjobs=1 --runtime=60 --name="read-bs512-job1" ----- and here is the error: ----- read-bs512-job1: (g=0): rw=read, bs=1K-1K/1K-1K, ioengine=sync, iodepth=1 Starting 1 process fio: first direct IO errored. File system may not support direct IO, or iomem_align= is bad. fio: pid=4898, err=22/file:engines/sync.c:62, func=xfer, error=Invalid argument read-bs512-job1: (groupid=0, jobs=1): err=22 (file:engines/sync.c:62, func=xfer, error=Invalid argument): pid=4898 cpu : usr=0.00%, sys=0.00%, ctx=0, majf=0, minf=50 IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=50.0%, 4=50.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% issued r/w/d: total=1/0/0, short=0/0/0 Run status group 0 (all jobs): Disk stats (read/write): dm-0: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=-nan%, aggrios=0/0, aggrmerge=0/0, aggrticks=0/0, aggrin_queue=0, aggrutil=0.00% sdb: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00% sdd: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00% sdc: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00% sde: ios=0/0, merge=0/0, ticks=0/0, in_queue=0, util=0.00 ----- testing the same volume with RAID10 works as expected. Is it related to the size of the volume? In RAID6 is 3.3TB and 2.1TB in RAID10. I've tried also with --norandommap but without success. and I've not understood what I have to put in iomem_align= to fix the "alignment" problem. Best regards, Christian -- Christian Zoffoli (XMerlin) You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete." -- R. Buckminster Fuller -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html