linux-raid.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: jeffs_linux@123mail.org
To: linux-raid@vger.kernel.org
Subject: Bug or not?  Same array reports different/transformed UUID depending on check-method used.
Date: Fri, 17 Jun 2011 09:29:49 -0700	[thread overview]
Message-ID: <1308328189.28028.1464311105@webmail.messagingengine.com> (raw)

I suppose I should split this into its own thread rather than burying it
in my other.

Question first:

  I have two arrays attached to my Linux box.  Two methods of checking
  for arrays UUIDs give different results.  Why, and can I reply on
  these arrays?

Details follow:

Checking with,

 mdadm --incremental --rebuild-map
 mdadm --detail --scan
  ARRAY /dev/md/0_0 metadata=0.90                      
  UUID=52f5b43c:e83f7e2a:be6ad32e:0536ab0e
  ARRAY /dev/md127  metadata=1.2  name=jeffadm:jeffadm1
  UUID=d47afb79:e5fa9b28:ff35c586:f2602920

and,

 cat /dev/.mdadm/map
  md126 0.90 52f5b43c:e83f7e2a:be6ad32e:0536ab0e /dev/md/0_0
  md127 1.2  79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127

Staring at those UUIDs, I notice that one array's UUIDs match exactly
for the two methods of checking,

 /dev/.mdadm/map       /dev/md/0_0  52f5b43c:e83f7e2a:be6ad32e:0536ab0e
 mdadm --detail --scan /dev/md/0_0  52f5b43c:e83f7e2a:be6ad32e:0536ab0e

but the OTHER array's two UUIDs

 /dev/.mdadm/map       /dev/md127   79fb7ad4:289bfae5:86c535ff:202960f2
 mdadm --detail --scan /dev/md127   d47afb79:e5fa9b28:ff35c586:f2602920

are 'transforms' of one another; e.g.,

 mdadm --detail --scan /dev/md127   d47afb79:e5fa9b28:ff35c586:f2602920

                                    d4       e5
                                      7a       fa
                                        fb       9b
                                          79:      28:...

                                        |
                                        |  couplet order transform
                                        |

                                          d4       e5
                                        7a       fa
                                      fb       9b
                                    79:      28:      ...

 /dev/.mdadm/map       /dev/md127   79fb7ad4:289bfae5:86c535ff:202960f2

Why are /dev/md127's UUIDs, unlike /dev/md/0_0's, reporting mis-matched
& 'transformed'?

jeff

             reply	other threads:[~2011-06-17 16:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-17 16:29 jeffs_linux [this message]
2011-06-21  5:42 ` Bug or not? Same array reports different/transformed UUID depending on check-method used Luca Berra
2011-06-21 12:50   ` jeffs_linux

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1308328189.28028.1464311105@webmail.messagingengine.com \
    --to=jeffs_linux@123mail.org \
    --cc=linux-raid@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).