Hi, I was writing a small fio job file to do writes and read verifies on a device. It forks 32 processes, each writing randomly to 4 files with a block size between 4k and 16k. When it has written 1024 of those blocks, it'll verify the oldest 512 of them. Each block is checksummed for every 512b. It uses libaio and O_DIRECT. It works on ext2 and btrfs. I haven't run it to completion yet, but they survive 15-20 minutes just fine. ext4 doesn't even go a full minutes before this triggers: Bad verify header 0 at 10137600 fio: pid=9943, err=84/file:io_u.c:1212, func=io_u_queued_complete, error=Invalid or incomplete multibyte or wide character writers: (groupid=0, jobs=32): err=84 (file:io_u.c:1212, func=io_u_queued_complete, error=Invalid or incomplete multibyte or wide character): pid=9943 which tells us that where we expected to find the correct verify magic in the header, it was all zeroes. The job file used is below, and to reproduce you want to use the latest fio (1.40) since some earlier versions don't do verify_interval properly for non-pattern verifies. You can get fio here: http://brick.kernel.dk/snaps/fio-1.40.tar.gz or from git at: git://git.kernel.dk/fio.git The kernel used is 2.6.35-rc3 and I ran this on a raid0 that had 8 SSD drives. --- snip job file --- [global] direct=1 group_reporting=1 exitall runtime=4h time_based=1 # writers, will repeatedly randomly write and verify data [writers] rw=randwrite bsrange=4k-16k ioengine=libaio iodepth=4 directory=/data verify=crc32c verify_backlog=1024 verify_backlog_batch=512 verify_interval=512 size=512m nrfiles=4 filesize=64m-256m numjobs=32 create_serialize=0 --- snip job file --- -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
