Neil introduced read-checking into 2.6.16. In versions prior, mirror copies were overwritten instead of checked. I'm running 2.6.17rc4: # echo "check" > /sys/block/md0/md/sync_action # dmesg md: syncing RAID array md0 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 15542784 blocks. # dstat -d -D sda,sdg --disk/sda----disk/sdg- _read write:_read write 81k 30k: 81k 30k 58M 0 : 58M 0 58M 0 : 57M 0 57M 0 : 58M 0 58M 0 : 57M 0 Although the message uses the word "reconscruction," the drives are being checked for consistancy. ----------------- I just tried the patch and now it seems to be syncing the drives instead of only checking them? (At the very least the message is misleading.) # echo "check" >/sys/block/md0/md/sync_action # dmesg | tail -9 md: syncing RAID array md0 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 104256 blocks. md: md0: sync done. RAID1 conf printout: --- wd:2 rd:2 disk 0, wo:0, o:1, dev:hda9 disk 1, wo:0, o:1, dev:sda5 - 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
