Why do I get different results for "mdadm --detail" & "mdadm --examine"for the same array?

Hi,

I'm working on setting up my 1st Linux production server with RAID for
our office.

I have four drives, across which I created two arrays.

mdadm --create /dev/md0 --verbose --bitmap=interal --metadata=0.90
--raid-devices=4 --homehost=jeffadm --name=jeffadm0 --level=raid1
/dev/sd[abcd]1

mdadm --create /dev/md1 --verbose --bitmap=interal --metadata=1.2
--raid-devices=4 --homehost=jeffadm --name=jeffadm1 --level=raid10
--layout=f2 --chunk=512 /dev/sd[abcd]2

After letting the arrays build an so on, I check to see:

fdisk -l | grep -i /dev/md | grep bytes
Disk /dev/md127 doesn't contain a valid partition table
Disk /dev/md126 doesn't contain a valid partition table
Disk /dev/md127: 1998.2 GB, 1998231437312 bytes
Disk /dev/md126: 1085 MB, 1085603840 bytes

cat /proc/mdstat
-----------------------------------
Personalities : [raid10] [raid0] [raid1] [raid6] [raid5] [raid4]
[linear]
md126 : active raid1 sda1[0] sdd1[3] sdc1[2] sdb1[1]
1060160 blocks [4/4] [UUUU]
bitmap: 0/130 pages [0KB], 4KB chunk

md127 : active raid10 sda2[0] sdd2[3] sdc2[2] sdb2[1]
1951397888 blocks super 1.2 512K chunks 2 far-copies [4/4] [UUUU]
bitmap: 11/466 pages [44KB], 2048KB chunk

unused devices:
-----------------------------------

For assembly at boot-up I created by hand,

cat /etc/mdadm.conf
-----------------------------------
DEVICE /dev/disk/by-id/ata-ST31000528AS_9VP37KJF-part1
/dev/disk/by-id/ata-ST31000528AS_9VP18C2L-part1
/dev/disk/by-id/ata-ST31000528AS_9VP18JXF-part1
/dev/disk/by-id/ata-ST31000528AS_6FD23G3U-part1

DEVICE /dev/disk/by-id/ata-ST31000528AS_9VP37KJF-part2
/dev/disk/by-id/ata-ST31000528AS_9VP18C2L-part2
/dev/disk/by-id/ata-ST31000528AS_9VP18JXF-part2
/dev/disk/by-id/ata-ST31000528AS_6FD23G3U-part2

ARRAY /dev/md/0_0 level=raid1 num-devices=4 metadata=0.90
UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e

ARRAY /dev/md/jeffadm:jeffadm1 level=raid10 num-devices=4 metadata=1.02
UUID=d84afb64:e6fa2b64:ff21c975:f9765431 name=name=jeffadm:jeffadm1
-----------------------------------

I installed a Linux system, across the RAID arrays. It boots up like I
expect. As far as I can tell, everything seems to work ok.



In case it's helpful,

dmesg | grep md
[ 5.312800] md: raid10 personality registered for level 10
[ 5.364552] md: raid0 personality registered for level 0
[ 5.379499] md: raid1 personality registered for level 1
[ 5.649211] md: raid6 personality registered for level 6
[ 5.649213] md: raid5 personality registered for level 5
[ 5.649214] md: raid4 personality registered for level 4
[ 8.450420] md: md127 stopped.
[ 8.461620] md: bind
[ 8.470479] md: bind
[ 8.479231] md: bind
[ 8.487931] md: bind
[ 8.512436] md/raid10:md127: active with 4 out of 4 devices
[ 8.529191] created bitmap (466 pages) for device md127
[ 8.554742] md127: bitmap initialized from disk: read 30/30 pages,
set 3952 bits
[ 8.599314] md127: detected capacity change from 0 to 1998231437312
[ 8.621493] md127: unknown partition table
[ 9.645318] md: linear personality registered for level -1
[ 12.397689] ata5: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xff00
irq 14
[ 12.397690] ata6: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xff08
irq 15
[ 18.127526] md: md126 stopped.
[ 18.138594] md: bind
[ 18.147113] md: bind
[ 18.155444] md: bind
[ 18.163804] md: bind
[ 18.172913] md/raid1:md126: active with 4 out of 4 mirrors
[ 18.186626] created bitmap (130 pages) for device md126
[ 18.201996] md126: bitmap initialized from disk: read 9/9 pages, set
0 bits
[ 18.225079] md126: detected capacity change from 0 to 1085603840
[ 18.240775] md126: unknown partition table
[ 20.429304] EXT4-fs (md126): mounted filesystem with ordered data
mode. Opts: acl,user_xattr,barrier=1
[ 84.109701] EXT4-fs (md126): re-mounted. Opts:
acl,user_xattr,barrier=1,commit=0


Now, I'm going about characterizing the arrays, and the Volumes on them,
so I can deal with recovery if & when it's necessary.

When I "look" at the array with these two commands,

mdadm --examine --scan
ARRAY /dev/md/jeffadm1 metadata=1.2
UUID=d84afb64:e6fa2b64:ff21c975:f9765431 name=jeffadm:jeffadm1
ARRAY /dev/md126 UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e

mdadm --detail --scan
ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
UUID=d84afb64:e6fa2b64:ff21c975:f9765431
ARRAY /dev/md/0_0 metadata=0.90
UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e


I get different results for each one.

From my reading about naming in mdadm.conf, I was expecting to see:

/dev/md/0_0
/dev/jeffadm:jeffadm1


Why do I get this mix of different results,

/dev/md/jeffadm1
/dev/md126

from the "--detail" output, and

/dev/md127 metadata=1.2 name=jeffadm:jeffadm1
/dev/md/0_0

according to the "--examine" output?

Is my mdadm.conf OK? What really should I expect to see for the names
of my arrays?

Jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Sat, 11 Jun 2011 18:01 -0700, jeffs_linux@123mail.org wrote:
> I'm working on setting up my 1st Linux production server with RAID for
> our office.

I was digging through my logs and found these 'failed' notices,

grep mdadm /var/log/*
/var/log/boot.msg:udevd[360]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[363]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[364]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[366]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[367]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[377]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[382]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[383]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[426]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[427]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[428]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:udevd[431]: exec of program '/bin/grep -qs '^AUTO
-all' /etc/mdadm.conf' failed
/var/log/boot.msg:mdadm: /dev/md127 has been started with 4 drives.
/var/log/boot.msg:Starting MD Raid mdadm: /dev/md/0_0 has been started
with 4 drives.
/var/log/boot.msg: mdadmd start
/var/log/boot.msg:Starting mdadmd
/var/log/boot.msg: startproc:
execve (/sbin/mdadm) [ /sbin/mdadm -F -d 60 -m root@localhost -s -c
/etc/mdadm.conf ], [ DO_FASTBOOT=no CONSOLE=/dev/console SELINUX_INIT=NO
ROOTFS_FSTYPE=ext4 SHELL=/bin/sh TERM=dumb ROOTFS_FSCK=0 LC_ALL=POSIX
INIT_VERSION=sysvinit-2.89 DO_BLOGD=yes REDIRECT=/dev/ttyS0 COLUMNS=80
PATH=/bin:/sbin:/usr/bin:/usr/sbin vga=0x31a DO_CONFIRM=no RUNLEVEL=5
PWD=/
SPLASHCFG=/etc/bootsplash/themes/openSUSE/config/bootsplash- 1280x1024.cfg
DO_QUIET=no PREVLEVEL=N LINES=24 HOME=/ SHLVL=2 DO_FORCEFSCK=no
SPLASH=yes ROOTFS_BLKDEV=/dev/VG0/ROOT0 _=/sbin/startproc
DAEMON=/sbin/mdadm ]
/var/log/boot.msg:'mdadmd start' exits with status 0

I also found this file,

cat /dev/.mdadm/map
------------------------------------------------------------ ---
md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
------------------------------------------------------------ ---

which I think is created maybe by udevd that's complaining about all
those failures above?

What's unexpected is that 'map' files /dev/md0_0 UUID matches the
"--detail" scan, but the UUID for the /dev/md127 device is different !?

mdadm --detail --scan
ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
UUID=d84afb64:e6fa2b64:ff21c975:f9765431
ARRAY /dev/md/0_0 metadata=0.90
UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e

I'm pretty confused about what IS versus what SHOULD BE happening, or
whether I should delete/modify something, so I'm going to hold-off any
changes and hope somebody can shed some light.

Jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

and, one more bit of information

ls -al /dev/md*
brw-rw---- 1 root disk 9, 126 Jun 11 16:52 /dev/md126
brw-rw---- 1 root disk 9, 127 Jun 11 16:51 /dev/md127

/dev/md:
total 0
drwxr-xr-x 2 root root 60 Jun 11 16:52 ./
drwxr-xr-x 22 root root 5560 Jun 11 17:15 ../
lrwxrwxrwx 1 root root 8 Jun 11 16:52 0_0 -> ../md126

Jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

anyone?

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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Sat, 11 Jun 2011 18:01:11 -0700 jeffs_linux@123mail.org wrote:

> Hi,
>
> I'm working on setting up my 1st Linux production server with RAID for
> our office.

---- cut lots of detail-----
It is very good to include lots of detail, but more effective you include it
after you have asked the question, otherwise one gets bored long before one
reaches the actual question....

>
>
> Now, I'm going about characterizing the arrays, and the Volumes on them,
> so I can deal with recovery if & when it's necessary.
>
> When I "look" at the array with these two commands,
>
> mdadm --examine --scan
> ARRAY /dev/md/jeffadm1 metadata=1.2
> UUID=d84afb64:e6fa2b64:ff21c975:f9765431 name=jeffadm:jeffadm1
> ARRAY /dev/md126 UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
>
> mdadm --detail --scan
> ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
> UUID=d84afb64:e6fa2b64:ff21c975:f9765431
> ARRAY /dev/md/0_0 metadata=0.90
> UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
>
>
> I get different results for each one.

It is just the different names that has you bothered - correct?

Names are messy things. We pretend that everything has just one name but
that isn't really true (reminds me of "The Traveller in Black" ... he had
many names but one nature. But I digress).

In the two different cases the 'name' of the array is found in different ways.
Both are correct, they are just different.

So unless there is some real confusion being caused, best just to move on and
not let it worry you..

NeilBrown



>
> >From my reading about naming in mdadm.conf, I was expecting to see:
>
> /dev/md/0_0
> /dev/jeffadm:jeffadm1
>
>
> Why do I get this mix of different results,
>
> /dev/md/jeffadm1
> /dev/md126
>
> from the "--detail" output, and
>
> /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
> /dev/md/0_0
>
> according to the "--examine" output?
>
> Is my mdadm.conf OK? What really should I expect to see for the names
> of my arrays?
>
> Jeff
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Thu, 16 Jun 2011 10:18 +1000, "NeilBrown" wrote:
> ---- cut lots of detail-----
> It is very good to include lots of detail, but more effective you include
> it
> after you have asked the question, otherwise one gets bored long before
> one
> reaches the actual question....

Ok. I got beaten up for top posting once, and was told to 'keep things
in order'. Next time, though -- question first, in BOTH the title and
the body.

> > I get different results for each one.
>
> It is just the different names that has you bothered - correct?

No, not just the names. I guess I don't know the PURPOSE of the names,
if the names we give things aren't necessarily the ones that get used.

But more a problem are the different UUID's:.

cat /dev/.mdadm/map
------------------------------------------------------------ ---
md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
------------------------------------------------------------ ---

mdadm --detail --scan
ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
UUID=d84afb64:e6fa2b64:ff21c975:f9765431
ARRAY /dev/md/0_0 metadata=0.90
UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e


Notice that the UUIDs for /dev/md/0_0 match, but for /dev/md127 the
don't.


jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Wed, 15 Jun 2011 17:39:14 -0700 jeffs_linux@123mail.org wrote:

>
>
> On Thu, 16 Jun 2011 10:18 +1000, "NeilBrown" wrote:
> > ---- cut lots of detail-----
> > It is very good to include lots of detail, but more effective you include
> > it
> > after you have asked the question, otherwise one gets bored long before
> > one
> > reaches the actual question....
>
> Ok. I got beaten up for top posting once, and was told to 'keep things
> in order'. Next time, though -- question first, in BOTH the title and
> the body.

:-) You can't win, can you...

>
> > > I get different results for each one.
> >
> > It is just the different names that has you bothered - correct?
>
> No, not just the names. I guess I don't know the PURPOSE of the names,
> if the names we give things aren't necessarily the ones that get used.

Well there is the names that people like to use (/dev/md/jeffadm) and names
that the kernel likes to use (md1, md2, md127).

When you use --examine, it tries to use the name that people might like.
When you use --detail --scan it primarily has access to the names the kernel
likes, so it used those.

>
> But more a problem are the different UUID's:.
>
> cat /dev/.mdadm/map
> ------------------------------------------------------------ ---
> md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
> md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
> ------------------------------------------------------------ ---
>
> mdadm --detail --scan
> ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
> UUID=d84afb64:e6fa2b64:ff21c975:f9765431
> ARRAY /dev/md/0_0 metadata=0.90
> UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e

Yes, that it weird. I don't know how they came to be out of sync.

mdadm --incremental --rebuild-map

will fix it..

NeilBrown


>
>
> Notice that the UUIDs for /dev/md/0_0 match, but for /dev/md127 the
> don't.
>
>
> jeff

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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Thu, 16 Jun 2011 11:22 +1000, "NeilBrown" wrote:
> > Ok. I got beaten up for top posting once, and was told to 'keep things
> > in order'. Next time, though -- question first, in BOTH the title and
> > the body.
>
> :-) You can't win, can you...

Not even checkers with my son ;-)

> When you use --examine, it tries to use the name that people might like.
> When you use --detail --scan it primarily has access to the names the
> kernel
> likes, so it used those.

Thanks for that. Into my notes ...

> > cat /dev/.mdadm/map
> > ------------------------------------------------------------ ---
> > md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
> > md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
> > ------------------------------------------------------------ ---
> >
> > mdadm --detail --scan
> > ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
> > UUID=d84afb64:e6fa2b64:ff21c975:f9765431
> > ARRAY /dev/md/0_0 metadata=0.90
> > UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
>
> Yes, that it weird. I don't know how they came to be out of sync.
>
> mdadm --incremental --rebuild-map
>
> will fix it..

Ok. This is officially the first time that I'll actually try to fix
anything on my 'production' array.

I'm reading the manpage -- again! -- and see both the "--incremental"
and "--rebuild-map" sections. So I get what they do.

WHEN can/should I do it? On my live running array while at runlevel 5?
A lower runlevel? From a separate boot disk?

jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Wed, 15 Jun 2011 18:47:36 -0700 jeffs_linux@123mail.org wrote:

>> > > cat /dev/.mdadm/map
> > > ------------------------------------------------------------ ---
> > > md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
> > > md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
> > > ------------------------------------------------------------ ---
> > >
> > > mdadm --detail --scan
> > > ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
> > > UUID=d84afb64:e6fa2b64:ff21c975:f9765431
> > > ARRAY /dev/md/0_0 metadata=0.90
> > > UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
> >
> > Yes, that it weird. I don't know how they came to be out of sync.
> >
> > mdadm --incremental --rebuild-map
> >
> > will fix it..
>
> Ok. This is officially the first time that I'll actually try to fix
> anything on my 'production' array.
>
> I'm reading the manpage -- again! -- and see both the "--incremental"
> and "--rebuild-map" sections. So I get what they do.
>
> WHEN can/should I do it? On my live running array while at runlevel 5?
> A lower runlevel? From a separate boot disk?
>

Any time at all is fine. The 'map' file is used to help with incremental
assembly of arrays. When "mdadm -I" is given a device that looks like part of
an array it looks in the map file to find out if any of that array has already
been assembled.
So one everything is assembled it is not interesting any longer.

I think you can even just remove it. If mdadm needs it and finds it doesn't
exist, it perform the equivalent of "mdadm --incremental --rebuild", then
tries again.

So it really is safe to run it at any time that you aren't actively rebooting
or plugging in new devices.

NeilBrown
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Thu, 16 Jun 2011 12:00 +1000, "NeilBrown" wrote:
> So it really is safe to run it at any time that you aren't actively
> rebooting or plugging in new devices.

gulp. i'll give it a try!

thanks,

jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On Thu, 16 Jun 2011 12:00 +1000, "NeilBrown" wrote:
> On Wed, 15 Jun 2011 18:47:36 -0700 jeffs_linux@123mail.org wrote:
>
> >> > > cat /dev/.mdadm/map
> > > > ------------------------------------------------------------ ---
> > > > md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
> > > > md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
> > > > ------------------------------------------------------------ ---
> > > >
> > > > mdadm --detail --scan
> > > > ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
> > > > UUID=d84afb64:e6fa2b64:ff21c975:f9765431
> > > > ARRAY /dev/md/0_0 metadata=0.90
> > > > UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
> > >
> > > Yes, that it weird. I don't know how they came to be out of sync.
> > > mdadm --incremental --rebuild-map
> > > will fix it..

cat /dev/.mdadm/map
md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0
md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2 /dev/md127
mdadm --incremental --rebuild-map
cat /dev/.mdadm/map
md127 1.2 79fb7ad4:289bfae5:86c535ff:202960f2
/dev/md/jeffadm:jeffadm1
md126 0.90 19f2b21c:e54f9e1a:be5ad16e:9754ab5e /dev/md/0_0

Notice that the UUIDs did NOT change, and are thus still out of sync.

BUT, the names did ...

Jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

repeating the process on another box, i just noticed that these two
results' UUIDs match exactly,

/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

what's happening here? that can't be a coincidence.

is this a bug? or maybe an artifact of the type of array?

jeff
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Re: Why do I get different results for "mdadm --detail" & "mdadm--examine" for the same array?

On the basis of this stunning review I have ordered a copy of 'The
Traveller in Black' from amazon :-)
You should be in sales ;-)
Simon

On 16 Jun 2011, at 01:18, NeilBrown wrote:

> On Sat, 11 Jun 2011 18:01:11 -0700 jeffs_linux@123mail.org wrote:
>
>> Hi,
>>
>> I'm working on setting up my 1st Linux production server with RAID for
>> our office.
>
> ---- cut lots of detail-----
> It is very good to include lots of detail, but more effective you include it
> after you have asked the question, otherwise one gets bored long before one
> reaches the actual question....
>
>>
>>
>> Now, I'm going about characterizing the arrays, and the Volumes on them,
>> so I can deal with recovery if & when it's necessary.
>>
>> When I "look" at the array with these two commands,
>>
>> mdadm --examine --scan
>> ARRAY /dev/md/jeffadm1 metadata=1.2
>> UUID=d84afb64:e6fa2b64:ff21c975:f9765431 name=jeffadm:jeffadm1
>> ARRAY /dev/md126 UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
>>
>> mdadm --detail --scan
>> ARRAY /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
>> UUID=d84afb64:e6fa2b64:ff21c975:f9765431
>> ARRAY /dev/md/0_0 metadata=0.90
>> UUID=19f2b21c:e54f9e1a:be5ad16e:9754ab5e
>>
>>
>> I get different results for each one.
>
> It is just the different names that has you bothered - correct?
>
> Names are messy things. We pretend that everything has just one name but
> that isn't really true (reminds me of "The Traveller in Black" ... he had
> many names but one nature. But I digress).
>
> In the two different cases the 'name' of the array is found in different ways.
> Both are correct, they are just different.
>
> So unless there is some real confusion being caused, best just to move on and
> not let it worry you..
>
> NeilBrown
>
>
>
>>
>>> From my reading about naming in mdadm.conf, I was expecting to see:
>>
>> /dev/md/0_0
>> /dev/jeffadm:jeffadm1
>>
>>
>> Why do I get this mix of different results,
>>
>> /dev/md/jeffadm1
>> /dev/md126
>>
>> from the "--detail" output, and
>>
>> /dev/md127 metadata=1.2 name=jeffadm:jeffadm1
>> /dev/md/0_0
>>
>> according to the "--examine" output?
>>
>> Is my mdadm.conf OK? What really should I expect to see for the names
>> of my arrays?
>>
>> Jeff
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