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From: Martin Steigerwald <Martin@lichtvoll.de>
To: linux-btrfs@vger.kernel.org, helmut@hullen.de
Subject: Re: read error: how to fix?
Date: Sat, 15 Oct 2011 20:47:33 +0200	[thread overview]
Message-ID: <201110152047.34228.Martin@lichtvoll.de> (raw)
In-Reply-To: <Bv$GAecT1uB@helmut.hullen.de>

Hi Helmut,

Am Montag, 10. Oktober 2011 schrieb Helmut Hullen:
> > The thing is that marking sectors bad is a
> > (pretty poor) band-aid for a much bigger problem: If you're hitting
> > persistent read errors and re-writing the blocks doesn't fix it, your
> > disk is already close to being completely kaput and no amount of
> > software is going to help with that.
> 
> The next steps could be:
> 
> - adding a new 2-TByte disk (now there are 3 2-TByte disks)
> - balancing
> - removing the bad 2-TByte disk
> 
> But I'm afraid when I run balancing then the bad sectors damage big  
> parts of the contents. I've had such bad luck about 1 year ago,
> losing   about 2 TByte of data (ok - I had a kind of backup in a
> neighbout town). I don't like to reproduce this experience.
> 
> I'm afraid I have to buy 3 (or 4) 2-TByte disks, building them as a
> new   raid0-data cluster and copy the complete contents from the old
> cluster to the new one. Doesn't sound good.

RAID-0 and valuable (?) data does not match together. So if you go 4 
disks, consider a RAID 10 ;). Then you could set the disk faulty, put in a 
new one and let BTRFS resync/balance the RAID. But if everything is only 
stored on one disk thats not possible.

A RAID 5 might also be an alternative, but I am not sure, whether RAID-5 
is already working with BTRFS. I heard about plans to borrow some SoftRAID 
code for that.

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7

  parent reply	other threads:[~2011-10-15 18:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-07 16:51 read error: how to fix? Helmut Hullen
2011-10-10 11:48 ` David Sterba
2011-10-10 13:28   ` Helmut Hullen
2011-10-10 14:07     ` Jeff Mahoney
2011-10-10 15:58       ` Helmut Hullen
2011-10-14 19:47         ` Jeff Mahoney
2011-10-15 18:47         ` Martin Steigerwald [this message]
2011-10-15 19:59           ` Helmut Hullen
2011-10-16 19:32             ` Calvin Walton
2011-10-17  3:35               ` Helmut Hullen
2011-10-18 15:33               ` Helmut Hullen
2011-10-21  9:40               ` Helmut Hullen

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