On 10/18/22 09:35, [email protected] wrote:
I have raid1 volume (one of two on PC) with 2 disks.# disklabel sd5 # /dev/rsd5c: type: SCSI disk: SCSI disk label: SR RAID 1 duid: 7a03a84165b3d165 flags: bytes/sector: 512 sectors/track: 63 tracks/cylinder: 255 sectors/cylinder: 16065 cylinders: 243201 total sectors: 3907028640 boundstart: 0 boundend: 3907028640 drivedata: 0 16 partitions: # size offset fstype [fsize bsize cpg] a: 3907028608 0 4.2BSD 8192 65536 52270 # /home/vmail c: 3907028640 0 unused Recently I got an error in dmesg mail# dmesg | grep retry sd5: retrying read on block 767483392 (This happened during copying process) and system marked volume as degraded mail# bioctl sd5 Volume Status Size Device softraid0 1 Degraded 2000398663680 sd5 RAID1 0 Online 2000398663680 1:0.0 noencl <sd2a> 1 Offline 2000398663680 1:1.0 noencl <sd3a> I tried to reread this sector (and a couple around) with dd to make sure the sector is unreadable: mail# dd if=/dev/rsd3c of=/dev/null bs=512 count=16 skip=767483384 16+0 records in 16+0 records out 8192 bytes transferred in 0.025 secs (316536 bytes/sec) mail# dd if=/dev/rsd5c of=/dev/null bs=512 count=16 skip=767483384 16+0 records in 16+0 records out 8192 bytes transferred in 0.050 secs (161303 bytes/sec) but error did not appeared. Are there any methods to check if sector is bad (preferably on the fly)? If this is not a disk error (im going to replace cables just in case) should i just get disk back online with bioctl -R /dev/sd3a sd5 ?
You made some assumptions about the math that the disk uses vs. the math dd uses, and I'm not sure I agree with them. I'd suggest doing a dd read of the entire disk (rsd3c), rather than trying to read just the one sector. Remember, there's an offset between the sectors of sd5 (the softraid drive) and sd2 & sd3 where sd5 lives. So I'd kinda expect your sd3 check to pass because you missed the bad spot, and I'd expect your sd5 check to pass because the bad drive is locked out of the array and no longer a problem. IF you are a cheap ******* or the machine is in another country, you might want to try dd'ing zeros and 0xff's over the entire disk before putting it back in the array. That sometimes triggers a discovery of a bad spot and locks it out and replaces it with a spare. I've had some success with this process, actually, though it's a bad idea. :) Nick.
