From: Giovanni Tessore <giotex@texsoft.it>
To: linux-raid@vger.kernel.org
Subject: Re: Read errors on raid5 ignored, array still clean .. then disaster !!
Date: Mon, 01 Feb 2010 16:51:51 +0100 [thread overview]
Message-ID: <4B66F897.8060100@texsoft.it> (raw)
In-Reply-To: <20100201132703.GA29849@maude.comedia.it>
> modern drives _have_ correctable read errors, it is a fact.
> So if md kicked drives on read error it is also possible to lose all
> data on multiple failures (read errors on more than one drives, or
> read-errors when sparing), that could have been recovered.
But if we assume that modern drives behave like this, we should also
assume that radid 5, 4, 10 and 1 with < 3 devices, are intrinsically
vulnerable, and someway 'deprecated', because a read error on
recostruction after a disk failure can likely occur.
Personally I just reshaped the failed array as a 6-disk raid-6.
I'll also reshape another machine which has 3 disks to have 2 arrays, a
raid-1 with 3 devices and a raid-5, the first to be used for most
valuable data.
>> The new one must at least clearly alert the user that a drive is
>> getting read errors on raid 1,4,5,10.
> Agreed, now let's define 'clearly alert', besides syslog.
I would use the same mechanism of events used now my mdadm, defining new
CorrectedReadError event ... for raid-6 it can be info (or warning when
errors becamo too many,configurable); for other raid levels (the
'vulnerable' ones) the severity should be warning or critical.
--
Cordiali saluti.
Yours faithfully.
Giovanni Tessore
next prev parent reply other threads:[~2010-02-01 15:51 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-26 22:28 Read errors on raid5 ignored, array still clean .. then disaster !! Giovanni Tessore
2010-01-27 7:41 ` Luca Berra
2010-01-27 9:01 ` Goswin von Brederlow
2010-01-29 10:48 ` Neil Brown
2010-01-29 11:58 ` Goswin von Brederlow
2010-01-29 19:14 ` Giovanni Tessore
2010-01-30 7:58 ` Luca Berra
2010-01-30 15:52 ` Giovanni Tessore
2010-01-30 7:54 ` Luca Berra
2010-01-30 10:55 ` Giovanni Tessore
2010-01-30 18:44 ` Giovanni Tessore
2010-01-30 21:41 ` Asdo
2010-01-30 22:20 ` Giovanni Tessore
2010-01-31 1:23 ` Roger Heflin
2010-01-31 10:45 ` Giovanni Tessore
2010-01-31 14:08 ` Roger Heflin
2010-01-31 14:31 ` Asdo
2010-02-01 10:56 ` Giovanni Tessore
2010-02-01 12:45 ` Asdo
2010-02-01 15:11 ` Giovanni Tessore
2010-02-01 13:27 ` Luca Berra
2010-02-01 15:51 ` Giovanni Tessore [this message]
2010-01-27 9:01 ` Asdo
2010-01-27 10:09 ` Giovanni Tessore
2010-01-27 10:50 ` Asdo
2010-01-27 15:06 ` Goswin von Brederlow
2010-01-27 16:15 ` Giovanni Tessore
2010-01-27 19:33 ` Richard Scobie
-- strict thread matches above, loose matches on Subject: below --
2010-01-27 9:56 Giovanni Tessore
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