<br><font size=2 face="sans-serif">I've not had chance to read it all through
and will comment later when I have but one thought...</font>
<br>
<br><font size=2 face="sans-serif">I've had a lot of success sorting these
problems out by booting off a LiveCD and then imaging the disks with DD
etc and then trying to sort it allout in a virtual machine environment.
This obviously means of course you need a lot of spare disc in order to
do this. How much space are we talking about here?</font>
<br><font size=2 face="sans-serif"><br>
Chris Street MBCS<br>
Senior Server Engineer, European Datacentre.<br>
+44 (0)1423 580173; +44 (0)7717 366641</font>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td width=40%><font size=1 face="sans-serif"><b>Dave Fisher <wylug-discuss@davefisher.co.uk></b>
</font>
<br><font size=1 face="sans-serif">Sent by: wylug-discuss-bounces@wylug.org.uk</font>
<p><font size=1 face="sans-serif">29/05/2010 19:43</font>
<td width=59%>
<table width=100%>
<tr valign=top>
<td>
<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">wylug-discuss@wylug.org.uk</font>
<tr valign=top>
<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td>
<tr valign=top>
<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">[Wylug-discuss] Help needed with 'failed'
Linux software RAID 10</font></table>
<br>
<table>
<tr valign=top>
<td>
<td></table>
<br></table>
<br>
<br>
<br><tt><font size=2>Dear all,<br>
<br>
The other day, I posted a request to wylug-help concerning a serious<br>
(for me) RAID failure, but got no reply, so I'm trying again via<br>
wylug-discuss (with appologies).<br>
<br>
I know that many wylug members are RAID experts (at least in<br>
comparison with me), so I guess that either I didn't express myself<br>
properly, no-one uses wylug-help any more, or everyone hates me ;-)<br>
<br>
In the first instance, the only help I'm asking for is advice on how<br>
to carry out safe diagnostics and how to interpret the results.<br>
<br>
To give you some idea of the facts that I've already established, I've<br>
copied the output from some simple diagnostics in a text attachment.<br>
<br>
I might be completely missing the obvious, but some salient points seem
to be:<br>
<br>
a) LVM2 logical volumes sit on top of a RAID 10 array<br>
b) mdadm --examine shows partition names/IDs and statuses to be mixed<br>
up, like my last RAI failure<br>
c) That last failure was 'fixed' by finding the right incantation
to<br>
re-assemble and re-sync<br>
d) One problem, then as now, was to identify which pairs of<br>
partitions make up the each side of the mirror<br>
e) There seems to be no superblock detected for the whole device
(md1)<br>
f) The spare (sdj4) seems to be invisible in proc<br>
g) The report of md0 on sdi2 is a red herring - left over from the<br>
incomplete removal of md0<br>
<br>
<br>
Some questions<br>
-------------<br>
<br>
a) My, admittedly dodgy, understanding of RAID 10 is that if I can ID<br>
the two halves of a pair, I should be able to mount the pair like<br>
normal partitions or LVM volumes. Is this correct?<br>
<br>
b) Is it possible to readonly mount the md1 partitions in their<br>
current state - safely, without screwing-up further?<br>
<br>
Any interpretation of the attached data, or advice on further safe<br>
diagnostics would be appreciated.<br>
<br>
Dave<br>
_______________________________________________<br>
Wylug-discuss mailing list<br>
Wylug-discuss@wylug.org.uk<br>
https://mailman.lug.org.uk/mailman/listinfo/wylug-discuss<br>
</font></tt>
<br>
-----------------------------------------
The information contained in this communication (including any
attachments hereto) is confidential and is intended solely for the
personal and confidential use of the individual or entity to whom
it is addressed. If the reader of this message is not the intended
recipient or an agent responsible for delivering it to the intended
recipient, you are hereby notified that you have received this
communication in error and that any review, dissemination, copying,
or unauthorized use of this information, or the taking of any
action in reliance on the contents of this information is strictly
prohibited. If you have received this communication in error,
please notify us immediately by e-mail, and delete the original
message. Thank you