this has never happened to me before, and I'm somewhat at a loss. got a email from the cron thing... /etc/cron.weekly/99-raid-check: WARNING: mismatch_cnt is not 0 on /dev/md10 WARNING: mismatch_cnt is not 0 on /dev/md11 ok, md10 and md11 are each raid1's made from 2 x 72GB scsi drives, on a dell 2850 or something dual single-core 3ghz server. these two md's are in turn a striped LVM volume group dmesg shows.... md: syncing RAID array md10 md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc. md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reconstruction. md: using 128k window, over a total of 143374656 blocks. md: syncing RAID array md11 md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc. md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reconstruction. md: using 128k window, over a total of 143374656 blocks. md: md10: sync done. RAID1 conf printout: --- wd:2 rd:2 disk 0, wo:0, o:1, dev:sdc1 disk 1, wo:0, o:1, dev:sdd1 md: md11: sync done. RAID1 conf printout: --- wd:2 rd:2 disk 0, wo:0, o:1, dev:sde1 disk 1, wo:0, o:1, dev:sdf1 I'm not sure what thats telling me. the last thing prior to this in dmesg was when I added a swap to this vg last week. and mdadm --detail shows... # mdadm --detail /dev/md10 /dev/md10: Version : 0.90 Creation Time : Wed Oct 8 12:54:48 2008 Raid Level : raid1 Array Size : 143374656 (136.73 GiB 146.82 GB) Used Dev Size : 143374656 (136.73 GiB 146.82 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 10 Persistence : Superblock is persistent Update Time : Sun Feb 28 04:53:29 2010 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : b6da4dc5:c7372d6e:63f32b9c:49fa95f9 Events : 0.84 Number Major Minor RaidDevice State 0 8 33 0 active sync /dev/sdc1 1 8 49 1 active sync /dev/sdd1 # mdadm --detail /dev/md11 /dev/md11: Version : 0.90 Creation Time : Wed Oct 8 12:54:57 2008 Raid Level : raid1 Array Size : 143374656 (136.73 GiB 146.82 GB) Used Dev Size : 143374656 (136.73 GiB 146.82 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 11 Persistence : Superblock is persistent Update Time : Sun Feb 28 11:49:45 2010 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : be475cd9:b98ee3ff:d18e668c:a5a6e06b Events : 0.62 Number Major Minor RaidDevice State 0 8 65 0 active sync /dev/sde1 1 8 81 1 active sync /dev/sdf1 I don't see anything wrong here ? lvm shows no problems I detect either... # vgdisplay vg1 Volume group "vgdisplay" not found LV VG Attr LSize Origin Snap% Move Log Copy% Convert glassfish vg1 -wi-ao 10.00G lv1 vg1 -wi-ao 97.66G oradata vg1 -wi-ao 30.00G pgdata vg1 -wi-ao 25.00G pgdata_lss_idx vg1 -wi-ao 20.00G pgdata_lss_tab vg1 -wi-ao 20.00G swapper vg1 -wi-ao 3.00G vmware vg1 -wi-ao 50.00G # pvdisplay /dev/md10 /dev/md11 --- Physical volume --- PV Name /dev/md10 VG Name vg1 PV Size 136.73 GB / not usable 2.31 MB Allocatable yes PE Size (KByte) 4096 Total PE 35003 Free PE 1998 Allocated PE 33005 PV UUID oAgJY7-Tmf7-ac35-KoUH-15uz-Q5Ae-bmFCys --- Physical volume --- PV Name /dev/md11 VG Name vg1 PV Size 136.73 GB / not usable 2.31 MB Allocatable yes PE Size (KByte) 4096 Total PE 35003 Free PE 2560 Allocated PE 32443 PV UUID A4Qb3P-j5Lr-8ZEv-FjbC-Iczm-QkC8-bqP0zv