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

[sylvain.depuille@laposte.net]

Hello,

First good news of the year : the dirty Raid is online.

cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4] 
md2 : active raid5 sdc1[3] sdd1[2] sde1[4] sdb1[5]
      2930276352 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
      bitmap: 0/8 pages [0KB], 65536KB chunk


Many thank's for your help.

Now, i have unmounted all filesystems and do e2fsck on all.

With ext4, it's running very quickly, and no errors found. Is it reliable?
But it's may be not your part? ;-)

Thank's in advance
Best Regards

Sylvain Depuille (Happy).

----- 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: Mercredi 31 Décembre 2014 20:11:32 
Objet: Re: Re: Re : Re: Big trouble during reassemble a Raid5 

>>>>> "sylvain" == sylvain depuille <sylvain.depuille@laposte.net> writes: 

sylvain> Hi John, 
sylvain> I do the summary of disk and states : 
sylvain> /dev/sdb : 1TB : OK 
sylvain> /dev/sdc : 1TB : ?? 
sylvain> /dev/sdd : 2TB : ddrescued 
sylvain> /dev/sde : 3TB : Not synchronized 

sylvain> Something is wrong in this list. It seems that i have remove 
sylvain> a wrong disk. 

It might be that is the problem. One thing to do is to run 'smartctl' 
on all the disks and get the UUIDs/serial numbers so you can confirm 
which disk is which. 

The 'lsscsi' is also useful to help make sure you know which drives 
are mapped to which drive letter, since they can move around. But if 
you do get a chance, try what I suggested, which is to assemble with 
just three of the drives. Maybe don't even hook up /dev/sdc1 at all 
to the system. 

sylvain> I should investigate with my friends tomorrow evening for us, 
sylvain> afternoon for you. I will on the road tomorrow. And it is 
sylvain> may be free for you? 

I won't be around tomorrow afternoon, January 1st, I've got a birthday 
party to attend. I'll try to be online at some point, but it's not 
likely. 

sylvain> I wish you a good eve for this evening, and see you next year ;-). 

Happy New Year to you and your friends and family as well! Enjoy! I 
will talk with you in the new year for sure. 


sylvain> ----- Mail original ----- 
sylvain> De: "John Stoffel" <john@stoffel.org> 
sylvain> À: "Sylvain Depuille" <sylvain.depuille@laposte.net> 
sylvain> Cc: "John Stoffel" <john@stoffel.org> 
sylvain> Envoyé: Mercredi 31 Décembre 2014 18:27:03 
sylvain> Objet: Re: Re: Re : Re: Big trouble during reassemble a Raid5 


Sylvain> But the missing disk is the rescued disk! 

sylvain> I understand that, but we're looking to get the RAID5 up and working 
sylvain> again, but the event count looks wrong on that disk, so it shouldn't 
sylvain> be used to re-assemble the array. 

sylvain> There is going to be some data loss here, but let's minimize it and 
sylvain> get the array going again. 

Sylvain> And the 3TB should be rebuild, because i have change It just 
Sylvain> before the issue :-(sorry iPhone in French) 

sylvain> I think it's ok, since the other three disks have matching event 
sylvain> counts. It's the /dev/sdc1 that's behind the rest, so it needs to be 
sylvain> excluded at first. 

sylvain> Try it out and let me know. 


Sylvain> I haven't mailings list in copy because html :-( 
Sylvain> If necessary i Will revend the mail from House! 

Sylvain> Best Regards 
Sylvain> Sylvain Depuillr 

Sylvain> Envoyé depuis un telephone portable 

>>> Le 31 déc. 2014 à 17:08, John Stoffel <john@stoffel.org> a écrit : 
>>> 
>>> 
sylvain> It's my fault too, because the mailing list doesn't accept 
sylvain> HTML format. And my provider doesn't offer plain text option 
sylvain> with the mobile site :-( 
>>> 
>>> It's a total pain at times. I'm still reading email with plain ascii 
>>> most of the time, I don't care for HTML email generally since it just 
>>> gets in the way. 
>>> 
sylvain> Back to the issue : 
>>> 
sylvain> I have stop the raid. 
sylvain> mdadm --stop /dev/md2 
sylvain> mdadm: stopped /dev/md2 
>>> 
sylvain> cat /proc/mdstat 
sylvain> Personalities : [raid1] [raid6] [raid5] [raid4] 
sylvain> unused devices: <none> 
>>> 
sylvain> And when i try to re-assemble, the command is aborting : 
sylvain> mdadm --assemble --force /dev/md2 /dev/sd[bcde]1 
sylvain> mdadm: /dev/md2 assembled from 2 drives and 1 spare - not enough to start the array. 
>>> 
>>> So if I look at the event counts, there's a mismatch between 
>>> /dev/sd[bde]1 and /dev/sdc1. So let's try to assemble without /dev/sdc1: 
>>> 
>>> mdadm -vv --assemble --force /dev/md2 /dev/sdb1 missing /dev/sdd1 /dev/sde1 
>>> 
>>> and see what happens then. With three out of the four devices, the 
>>> RAID5 array should start up, and then you can add in /dev/sdc1 to 
>>> rebuild the parity. 
>>> 
>>> John 

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