Re: Re : Re: Big trouble during reassemble a Raid5

[sylvain.depuille@laposte.net]

Hello John, 

the ddrescue command is finished. 
The log file :
# Rescue Logfile. Created by GNU ddrescue version 1.18.1
# Command line: ddrescue --force /dev/sdc1 /dev/sdf1 rescue.log
# Start time:   2014-12-30 11:28:57
# Current time: 2014-12-30 13:40:29
# Copying non-tried blocks... Pass 1 (forwards)
# current_pos  current_status
0x89EE5A0000     ?
#      pos        size  status
0x00000000  0x87EB34F000  +
0x87EB34F000  0x00001000  *
0x87EB350000  0x00001000  +
0x87EB351000  0x0001F000  *
0x87EB370000  0x0015B000  +
0x87EB4CB000  0x00005000  *
0x87EB4D0000  0x0BA39000  +
0x87F6F09000  0x00007000  *
0x87F6F10000  0x1F76A0000  +
0x89EE5B0000  0x5EF2580400  ?

Now, can i change the sdc by the sdf disk?

Thank's in advance for your help.
Best Regards

Sylvain Depuille
----- Mail original ----- 
De: "John Stoffel" <john@stoffel.org> 
À: "sylvain depuille" <sylvain.depuille@laposte.net> 
Cc: "John Stoffel" <john@stoffel.org>, linux-raid@vger.kernel.org 
Envoyé: Lundi 29 Décembre 2014 21:36:23 
Objet: Re: Re : Re: Big trouble during reassemble a Raid5 


sylvain> Hi john, thanks for your answer! I have change a 1TB disk to 
sylvain> growing the raid with 3TB disk. if i can re-insert the old 
sylvain> 1TB disk in place of 3TB disk, only some log and history are 
sylvain> corrupted. i think that is the best way to relaunch the raid 
sylvain> without data loss. But i dont known how change the timestamp 
sylvain> of the one raid disk. Have you a magic command to change a 
sylvain> timestamp of a raid partition, and how known the timestamp of 
sylvain> the other disk of the raid? After' raid relaunch, i can 
sylvain> change the burn disk by a 3TB new one. To do the ddrescue, i 
sylvain> have a 2TB disk spare! Its not the same geometry, is it 
sylvain> possible? thanks in advance for your help 

Sylvain, 

Always glad to help here. I'm going to try and understand what you 
wrote and do my best to reply. 

Is the 1Tb disk the bad disk? And if you re-insert it and re-start 
the RAID5 array, you only have some minor lost files? If so, I would 
probably just copy all the data off the RAID5 onto the single 3Tb disk 
as a quick and dirty backup, then I'd use 'dd_rescue' to copy the bad 
1Tb disk onto the new 2Tb disk. 

All you would have to do is make a partition on the 2tb disk which is 
the same size (or a little bigger) than the partition on the 1tb disk, 
then copy the partition over like this: 

ddrescue /dev/sd[BAD DISK LETTER HERE]1 /dev/sd[2TB disk letter]1 \ 
/tmp/rescue.log 

So say the bad disk is sdc, and the good 2tb is sdf, you would do: 

ddrescue /dev/sdc1 /dev/sdf1 /tmp/rescue.log 

and let it go. Then you would assemble the array using the NEW 2tb 
disk. Ideally you would remove the bad 1tb disk from the system when 
trying to do this. 

But you really do need send us the output of the following commands: 

cat /proc/mdstat 
cat /proc/partitions 
mdadm --detail /dev/md# 

do the above for the RADI5 array. 

mdadm --examine /dev/sd#1 

for each disk in the RAID5 array. 

And we can give you better advice. 

Good luck! 


sylvain> ---------------------------------- Sylvain Depuille 
sylvain> sylvain.depuille@laposte.net ----- Mail d'origine ----- De: 
sylvain> John Stoffel <john@stoffel.org> À: sylvain depuille 
sylvain> <sylvain.depuille@laposte.net> Cc: linux-raid@vger.kernel.org 
sylvain> Envoyé: Mon, 29 Dec 2014 19:32:04 +0100 (CET) Objet: Re: Big 
sylvain> trouble during reassemble a Raid5 

sylvain> Sylvain, I would recommend that you buy a replacement disk 
sylvain> for the one throwing errors and then run dd_rescue to copy as 
sylvain> much data from the dying disk to the replacement. Then, and 
sylvain> only then, do you try to reassemble the array with the 
sylvain> --force option. That disk is dying, and dying quickly. Can 
sylvain> you also post the output of mdadm -E /dev/sd[bcde]1 for each 
sylvain> disk, even the dying one, so we can look at the counts and 
sylvain> give you some more advice. Also, the output of the mdadm 
sylvain> --assemble --force /dev/md2 /dev/sd[bcde]1 would also be 
sylvain> good. The more info the better. Good luck! John 

sylvain> i'm sorry to ask this questions but the raid 5 with 4 disk is 
sylvain> in big trouble during re-assemble. 2 disks are out of order. 
sylvain> I have change a disk of the raid 5 (sde) to growing the raid. 
sylvain> But a second disk (sdc) have too many bad sector during the 
sylvain> re-assemble, and shutdown the re-assemble. "mdadm --assemble 
sylvain> --force /dev/md2 /dev/sd[bcde]1" I have try to correct bad 
sylvain> sectors with badblocks, but it's finished by no more spare 
sylvain> sectors and the disk still have some bad sector. badblocks -b 
sylvain> 512 -o badblocks-sdc.txt -v -n /dev/sdc 1140170000 1140169336 
sylvain> 1140169400 1140169401 1140169402 1140169403 1140169404 
sylvain> 1140169405 1140169406 1140169407 1140169416 1140169417 
sylvain> 1140169418 1140169419 1140169420 1140169421 1140169422 
sylvain> 1140169423 

sylvain> For information the mdadm examine return : cat mdadm-exam.txt 
sylvain> /dev/sdb: MBR Magic : aa55 Partition[0] : 1953523120 sectors 
sylvain> at 2048 (type fd) /dev/sdc: MBR Magic : aa55 Partition[0] : 
sylvain> 1953520002 sectors at 63 (type fd) /dev/sdd: MBR Magic : aa55 
sylvain> Partition[0] : 1953520002 sectors at 63 (type fd) /dev/sde: 
sylvain> MBR Magic : aa55 Partition[0] : 4294965247 sectors at 2048 
sylvain> (type fd) I have 2 way to solve the issue. The first, is to 
sylvain> have special command to pass bad sector during re-assemble as 
sylvain> "mdadm --assemble --force /dev/md2 /dev/sd[bcde]1" The second 
sylvain> is change the disk sde with the old good one, but some datas 
sylvain> have been changed on the raid since i have remove it. But 
sylvain> these datas are not important. It's only logs and history 
sylvain> activity. What can i do to recover a maximum datas without 
sylvain> too many risk? Thank's in advance Best Regards 
sylvain> ---------------------------------- Sylvain Depuille (in 
sylvain> trouble) sylvain.depuille@laposte.net -- To unsubscribe from 
sylvain> this list: send the line "unsubscribe linux-raid" in the body 
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