From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Kich Subject: Re: Help in recovering a RAID5 volume Date: Thu, 10 Nov 2016 15:47:25 -0200 Message-ID: References: <5824A918.3030300@youngman.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <5824A918.3030300@youngman.org.uk> Sender: linux-raid-owner@vger.kernel.org To: Wols Lists Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi Anthony, Thanks for the reply. Here's some answers to your questions and also another question. It really seems that 2 disks are bad, but 2 are still good, according to SMART. I'll replace them ASAP. For now, I don't need to increase the array size. It's more than enough for what I need. About the drive duplication, I don't have spare discs available now for that, I only have one 4TB disk at hand, so I'd like to know if it's possible to create device images that I can mount and try to rebuild the array, to test if it would work, then I can go and buy new disks to replace the defective ones. And sure, I'll send you the logs you asked, no problem. Regards. - Felipe Kich 51-9622-2067 2016-11-10 15:06 GMT-02:00 Wols Lists : > On 10/11/16 15:41, Felipe Kich wrote: >> So, with that info, I could verify some things that are frequently >> mentioned on the posts: >> - SCT Error Recovery Control is disabled for both Read and Write operations; >> - Events counter in the devices are the same, except for one disk, but >> the difference is small (<50); >> - Magic Numbers and Checksums are all correct; >> >> Hope someone can give some advice as how to proceed next. >> > Okay. It says the drives are failing, so the first thing is to go out > and get four new drives :-( Ouch! > > Preferably WD Reds or Seagate NAS (Toshibas seem to support ERC too, I'm > not sure...) > > DON'T TOUCH A 3TB BARRACUDA. Barracudas aren't a good idea but the 3TB > disk is apparently an especially bad choice. > > Do you want to upgrade your array size? Or do you want to go Raid-6? > Four 2TB drives will give you a 4TB Raid-6 array. And look at getting 3- > or 4TB drives, they're good value for money. You might decide it's not > worth it. > > Copy and replace all the failing drives with ddrescue. Hopefully you'll > get a perfect copy. Don't worry that the old drive is smaller than the > new one if you get 2TB or larger drives. > > Assuming everything copies fine, find the three drives that are copies > of sda, sdb, sdd (ie the ones with the highest event counts), and > assemble with --force. You should now have a new array working fine. Do > a fsck to make sure everything's okay - you'll probably lose a file or > two :-( > > Add in the fourth disk - it'll trigger a rebuild, but that's normal. > > Now if your new disks are bigger than the old ones, you can expand the > array to use the space. You can either create a new partition in the > empty drive space for a third array, or you can use a utility to > move/expand the partitions. If you take the latter step, you should be > able to convert your raid-5 to a raid-6 (I'll let the experts chime in > on that). You can then expand the array to use all the available space, > and expand the filesystem on the array to use it. > > NB: If you don't get a perfect ddrescue copy, can you please email me > the log files - especially where it logs the blocks it can't copy. One > of the things I want to do is work out how to write that utility > mentioned on the "programming" page of the wiki. > > Cheers, > Wol >