Hi Neil I observed raid1 data corruption on raid1 test, below is the test env/reproduce steps/log, pls check it. Kernel-verison: 4.2.0-rc3 Test-steps: 1. First create one 2GB file bigfile 2. Execute below script #!/bin/bash Create_Loop() { for i in `seq 0 7`;do dd if=/dev/zero of=/tmp/$i.tmp bs=1M count=3000 & done wait for i in `seq 0 7`;do losetup /dev/loop$i /tmp/$i.tmp done } Prepare() { mdadm --create --run /dev/md0 --level 1 --metadata 1.2 --raid-devices 8 /dev/loop[0-7] --chunk 512 --bitmap=internal --bitmap-chunk=64M mdadm --wait /dev/md0 mkfs.ext4 /dev/md0 mkdir /mnt/fortest mount /dev/md0 /mnt/fortest md5sum bigfile >md5sum1 } Create_Loop Prepare cnt=0 while [ 1 ]; do echo "-----------------------------------------------------$cnt" cp bigfile /mnt/fortest & sleep 10 mdadm /dev/md0 -f /dev/loop0 sleep 5 mdadm /dev/md0 -r /dev/loop0 while [ 1 ]; do if [ $? -ne 0 ];then sleep 5 mdadm /dev/md0 -r /dev/loop0 else break fi done sleep 30 mdadm /dev/md0 -a /dev/loop0 wait echo "cp done" mdadm --wait /dev/md0 echo "recovery done" md5sum /mnt/fortest/bigfile > md5sum2 tmp1=`awk '{print $1}' ./md5sum1` tmp2=`awk '{print $1}' ./md5sum2` echo $tmp1 > a echo $tmp2 > b diff a b //data corruption observed if [ $? -ne 0 ]; then echo "There are some date corruption, cnt is $cnt" exit 1 fi ((cnt++)) rm -rf /mnt/fortest/bigfile done Kernel-Log: [ 1113.577378] loop: module loaded [ 1290.190065] md: bind<loop0> [ 1290.193214] md: bind<loop1> [ 1290.196387] md: bind<loop2> [ 1290.199542] md: bind<loop3> [ 1290.202704] md: bind<loop4> [ 1290.205854] md: bind<loop5> [ 1290.209003] md: bind<loop6> [ 1290.212170] md: bind<loop7> [ 1290.229799] md: raid1 personality registered for level 1 [ 1290.235946] md/raid1:md0: not clean -- starting background reconstruction [ 1290.243515] md/raid1:md0: active with 8 out of 8 mirrors [ 1290.249449] created bitmap (1 pages) for device md0 [ 1290.254927] md0: bitmap initialized from disk: read 1 pages, set 47 of 47 bits [ 1290.328736] md0: detected capacity change from 0 to 3143630848 [ 1290.335316] md: resync of RAID array md0 [ 1290.339689] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. [ 1290.346192] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for resync. [ 1290.356702] md: using 128k window, over a total of 3069952k. [ 1640.101181] md: md0: resync done. [ 1668.352287] EXT4-fs (md0): mounted filesystem with ordered data mode. Opts: (null) [ 1681.845966] md/raid1:md0: Disk failure on loop0, disabling device. [ 1681.845966] md/raid1:md0: Operation continuing on 7 devices. [ 1844.296614] md: unbind<loop0> [ 1844.302013] md: export_rdev(loop0) [ 1874.363488] md: bind<loop0> [ 1874.566435] md: recovery of RAID array md0 [ 1874.571006] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. [ 1874.577514] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for recovery. [ 1874.588224] md: using 128k window, over a total of 3069952k. [ 1889.487210] md: md0: recovery done. Test Log: -----------------------------------------------------0 mdadm: set /dev/loop0 faulty in /dev/md0 mdadm: hot removed /dev/loop0 from /dev/md0 mdadm: re-added /dev/loop0 cp done recovery done -----------------------------------------------------1 mdadm: set /dev/loop0 faulty in /dev/md0 mdadm: hot removed /dev/loop0 from /dev/md0 mdadm: re-added /dev/loop0 cp done recovery done 1c1 < c4eddcf325ba5741d37f164750412619 --- > 4444f8bbfb1d22f1731fb5b0c846ef8a There are some date corruption, cnt is 1 Best Regards, Yi Zhang -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html