trouble adding spare

trouble adding spare

[Max Waterman]

Hi,

I have a RAID5 array using 6 disks and 2 spares. I took one spare away 
for a few months for another purpose (OS X) and am having trouble adding 
it back in as a spare.

I can add it manually :

sudo /sbin/mdadm /dev/md2 -a /dev/sdi

but it doesn't want to add itself in after rebooting (the other spare is 
added ok).

I'm sure this is simple for someone...

Max.

/dev/md2:
        Version : 00.90
  Creation Time : Sat Aug  6 05:18:41 2005
     Raid Level : raid5
     Array Size : 976804480 (931.55 GiB 1000.25 GB)
  Used Dev Size : 195360896 (186.31 GiB 200.05 GB)
   Raid Devices : 6
  Total Devices : 8
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Wed Jan 14 11:27:11 2009
          State : clean
 Active Devices : 6
Working Devices : 8
 Failed Devices : 0
  Spare Devices : 2

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 15bfec75:595ac793:0914f8ee:862effd8
         Events : 0.9341278

    Number   Major   Minor   RaidDevice State
       0       8       80        0      active sync   /dev/sdf
       1       8       96        1      active sync   /dev/sdg
       2       8       16        2      active sync   /dev/sdb
       3       8       48        3      active sync   /dev/sdd
       4       8       32        4      active sync   /dev/sdc
       5       8       64        5      active sync   /dev/sde

       6       8      128        -      spare   /dev/sdi
       7       8      112        -      spare   /dev/sdh

..../etc/mdadm/mdadm.conf
DEVICE /dev/sd[bcdefghi]

# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR davidmaxwaterman@fastmail.co.uk

# definitions of existing MD arrays
ARRAY /dev/md2 level=raid5 num-devices=6 
UUID=15bfec75:595ac793:0914f8ee:862effd8 spares=2

Re: trouble adding spare

[Justin Piszcz]

On Wed, 14 Jan 2009, Max Waterman wrote:

> Hi,
>
> I have a RAID5 array using 6 disks and 2 spares. I took one spare away for a 
> few months for another purpose (OS X) and am having trouble adding it back in 
> as a spare.
>
> I can add it manually :
>
> sudo /sbin/mdadm /dev/md2 -a /dev/sdi
>
> but it doesn't want to add itself in after rebooting (the other spare is 
> added ok).
After reboot, show dmesg/logs, what is the error?  I would try:

1. mdadm --examine --scan
2. Put that info into mdadm.conf.
3. Reboot, see if its good.
4. Otherwise, remove the spare from the array, zero the mdadm superblock.
5. Re-add it to the array.
6. Worst case, zero out the drive and then re-add it and re-run step 1 and
    add the new information to mdadm.conf.

>
> I'm sure this is simple for someone...
>
> Max.
>
> /dev/md2:
>       Version : 00.90
> Creation Time : Sat Aug  6 05:18:41 2005
>    Raid Level : raid5
>    Array Size : 976804480 (931.55 GiB 1000.25 GB)
> Used Dev Size : 195360896 (186.31 GiB 200.05 GB)
>  Raid Devices : 6
> Total Devices : 8
> Preferred Minor : 2
>   Persistence : Superblock is persistent
>
>   Update Time : Wed Jan 14 11:27:11 2009
>         State : clean
> Active Devices : 6
> Working Devices : 8
> Failed Devices : 0
> Spare Devices : 2
>
>        Layout : left-symmetric
>    Chunk Size : 64K
>
>          UUID : 15bfec75:595ac793:0914f8ee:862effd8
>        Events : 0.9341278
>
>   Number   Major   Minor   RaidDevice State
>      0       8       80        0      active sync   /dev/sdf
>      1       8       96        1      active sync   /dev/sdg
>      2       8       16        2      active sync   /dev/sdb
>      3       8       48        3      active sync   /dev/sdd
>      4       8       32        4      active sync   /dev/sdc
>      5       8       64        5      active sync   /dev/sde
>
>      6       8      128        -      spare   /dev/sdi
>      7       8      112        -      spare   /dev/sdh
>
> ..../etc/mdadm/mdadm.conf
> DEVICE /dev/sd[bcdefghi]
>
> # auto-create devices with Debian standard permissions
> CREATE owner=root group=disk mode=0660 auto=yes
>
> # automatically tag new arrays as belonging to the local system
> HOMEHOST <system>
>
> # instruct the monitoring daemon where to send mail alerts
> MAILADDR davidmaxwaterman@fastmail.co.uk
>
> # definitions of existing MD arrays
> ARRAY /dev/md2 level=raid5 num-devices=6 
> UUID=15bfec75:595ac793:0914f8ee:862effd8 spares=2

Re: trouble adding spare

[Max Waterman]

Justin Piszcz wrote:
> After reboot, show dmesg/logs, what is the error?
There's no error specific to md - it seems to just ignore sdi. There are 
errors from 'sd' saying sdi has an unknown partition table - but I don't 
care about partition tables since I'm using the whole devices (ie 
/dev/sdi not /dev/sdi1 or whatever). /dev/sdh is the other spare.

Here's some bits from dmesg :

[    9.720380] sd 11:0:0:0: [sdi] 390721968 512-byte hardware sectors 
(200050 MB
)
[    9.720392] sd 11:0:0:0: [sdi] Write Protect is off
[    9.720395] sd 11:0:0:0: [sdi] Mode Sense: 00 3a 00 00
[    9.720413] sd 11:0:0:0: [sdi] Write cache: enabled, read cache: 
enabled, doe
sn't support DPO or FUA
[    9.720460] sd 11:0:0:0: [sdi] 390721968 512-byte hardware sectors 
(200050 MB
)
[    9.720471] sd 11:0:0:0: [sdi] Write Protect is off
[    9.720473] sd 11:0:0:0: [sdi] Mode Sense: 00 3a 00 00
[    9.720490] sd 11:0:0:0: [sdi] Write cache: enabled, read cache: 
enabled, doe
sn't support DPO or FUA
[    9.720493]  sdi: unknown partition table
[    9.725328] sd 11:0:0:0: [sdi] Attached SCSI disk
...
[   13.735948] md: md2 stopped.
[   13.755547] md: md2 stopped.
[   13.757496] md: bind<sdh>
[   13.757657] md: bind<sdg>
[   13.763358] Driver 'sr' needs updating - please use bus_type methods
[   13.767589] sr0: scsi3-mmc drive: 40x/40x cd/rw xa/form2 cdda tray
[   13.767594] Uniform CD-ROM driver Revision: 3.20
[   13.767692] sr 8:0:1:0: Attached scsi CD-ROM sr0
[   13.770178] md: md2 stopped.
[   13.770201] md: unbind<sdg>
[   13.803686] md: export_rdev(sdg)
[   13.803704] md: unbind<sdh>
[   13.806345] md: export_rdev(sdh)
[   13.809153] md: bind<sdg>
[   13.809290] md: bind<sdd>
[   13.809430] md: bind<sdh>
[   13.809577] md: bind<sdf>
[   13.812235] md: md2 stopped.
[   13.812250] md: unbind<sdf>
[   13.818201] md: export_rdev(sdf)
[   13.818217] md: unbind<sdh>
[   13.830018] md: export_rdev(sdh)
[   13.830024] md: unbind<sdd>
[   13.834004] md: export_rdev(sdd)
[   13.834011] md: unbind<sdg>
[   13.834262] md: export_rdev(sdg)
[   13.837616] md: bind<sdg>
[   13.837748] md: bind<sdb>
[   13.837870] md: bind<sdd>
[   13.837992] md: bind<sde>
[   13.838133] md: bind<sdh>
[   13.838280] md: bind<sdf>
[   13.847605] md: md2 stopped.
[   13.847620] md: unbind<sdf>
[   13.860054] md: export_rdev(sdf)
[   13.860063] md: unbind<sdh>
[   13.860091] md: export_rdev(sdh)
[   13.860096] md: unbind<sde>
[   13.860120] md: export_rdev(sde)
[   13.860126] md: unbind<sdd>
[   13.860149] md: export_rdev(sdd)
[   13.860154] md: unbind<sdb>
[   13.860176] md: export_rdev(sdb)
[   13.860182] md: unbind<sdg>
[   13.860204] md: export_rdev(sdg)
[   13.863504] md: bind<sdg>
[   13.863636] md: bind<sdb>
[   13.863759] md: bind<sdd>
[   13.863877] md: bind<sdc>
[   13.863999] md: bind<sde>
[   13.864139] md: bind<sdh>
[   13.864285] md: bind<sdf>
[   13.873381] raid5: device sdf operational as raid disk 0
[   13.873383] raid5: device sde operational as raid disk 5
[   13.873385] raid5: device sdc operational as raid disk 4
[   13.873387] raid5: device sdd operational as raid disk 3
[   13.873389] raid5: device sdb operational as raid disk 2
[   13.873391] raid5: device sdg operational as raid disk 1
[   13.873941] raid5: allocated 6312kB for md2
[   13.873944] raid5: raid level 5 set md2 active with 6 out of 6 
devices, algorithm 2
[   13.873947] RAID5 conf printout:
[   13.873948]  --- rd:6 wd:6
[   13.873950]  disk 0, o:1, dev:sdf
[   13.873952]  disk 1, o:1, dev:sdg
[   13.873953]  disk 2, o:1, dev:sdb
[   13.873955]  disk 3, o:1, dev:sdd
[   13.873957]  disk 4, o:1, dev:sdc
[   13.873958]  disk 5, o:1, dev:sde

I'll give the below a try...

Thanks,

Max.
> I would try:
>
> 1. mdadm --examine --scan
> 2. Put that info into mdadm.conf.
> 3. Reboot, see if its good.
> 4. Otherwise, remove the spare from the array, zero the mdadm superblock.
> 5. Re-add it to the array.
> 6. Worst case, zero out the drive and then re-add it and re-run step 1 
> and
>    add the new information to mdadm.conf.
>

Re: trouble adding spare

[Max Waterman]

Max Waterman wrote:
>> I would try:
>>
>> 1. mdadm --examine --scan
>> 2. Put that info into mdadm.conf.
It's already there - I think that's how I got the line in the first place.
>> 4. Otherwise, remove the spare from the array, zero the mdadm 
>> superblock.
How would I do this? I tried :

$ sudo /sbin/mdadm /dev/sdi --zero-superblock --force
mdadm: /dev/sdi does not appear to be an md device

Max.

Re: trouble adding spare

[Justin Piszcz]

On Wed, 14 Jan 2009, Max Waterman wrote:

> Max Waterman wrote:
>>> I would try:
>>> 
>>> 1. mdadm --examine --scan
>>> 2. Put that info into mdadm.conf.
> It's already there - I think that's how I got the line in the first place.
>>> 4. Otherwise, remove the spare from the array, zero the mdadm superblock.
> How would I do this? I tried :
>
> $ sudo /sbin/mdadm /dev/sdi --zero-superblock --force
> mdadm: /dev/sdi does not appear to be an md device
>
> Max.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Output from when I have run this in the past:
p34:~# mdadm --zero-superblock /dev/hde1
p34:~#

If that does not work, clean the drive out manually after removing it as 
a spare from the array:
dd if=/dev/zero of=/dev/sdi bs=1M

Then try to re-add it.

If that still does not work you may need to modify some additional bits 
possibly with/in regards to the spare itself, I only have one spare in my 
array and I use a partition with type (fd) for the spare.

The only other thing I can think of is the events for that spare were 
0.123 (example) and then after you installed OSX onto the drive, it could 
have deleted the superblock for mdadm from when it was created as a spare.

I have not fixed this problem in any of my use-cases, but it may(?) be 
necessary to re-write that superblock onto the spare so it is identified 
as such, however, how to do this, is a good question, it would probably be 
assembly or if that does not work you would need to create the array, 
assume clean (as you originally created it before) so the superblock is 
written to the spare.  This all seems too complicated though, there should 
(and probably) is a simpler way.

Justin.

Re: trouble adding spare

[Max Waterman]

Justin Piszcz wrote:
> Output from when I have run this in the past:
> p34:~# mdadm --zero-superblock /dev/hde1
> p34:~#
Ok, shuffling the args (why is it that the args are sometimes one way, 
and sometimes another?) made it at least run, but it made no difference 
to the device being added at boot-time.
>
> If that does not work, clean the drive out manually after removing it 
> as a spare from the array:
> dd if=/dev/zero of=/dev/sdi bs=1M
This is taking forever. Isn't there a way to force mdadm to ignore the 
contents and just add it? How about a specific 'dd' that targets 
whatever is on the disk that is causing the problem (partition table?)?
> Then try to re-add it.
>
> If that still does not work you may need to modify some additional 
> bits possibly with/in regards to the spare itself, I only have one 
> spare in my array and I use a partition with type (fd) for the spare.
>
> The only other thing I can think of is the events for that spare were 
> 0.123 (example) and then after you installed OSX onto the drive,
Well, I didn't install OSX on it...just formatted it on OSX - what's 
that? HFS+ or something? Anyway, it makes several different partitions 
for some reason. Do you think that's causing the problem?
> it could have deleted the superblock for mdadm from when it was 
> created as a spare.
I would expect it to have deleted everything on the drive.
>
> I have not fixed this problem in any of my use-cases, but it may(?) be 
> necessary to re-write that superblock onto the spare so it is 
> identified as such, however, how to do this, is a good question, it 
> would probably be assembly or if that does not work you would need to 
> create the array, assume clean (as you originally created it before) 
> so the superblock is written to the spare.  This all seems too 
> complicated though, there should (and probably) is a simpler way.
That's kind of that I was thinking...

Thanks for your continued help though :)

Max.

Re: trouble adding spare

[Max Waterman]

Max Waterman wrote:
>>
>> If that does not work, clean the drive out manually after removing it 
>> as a spare from the array:
>> dd if=/dev/zero of=/dev/sdi bs=1M
> This is taking forever
I stopped it after about half an hour, hoping that it had made garbage 
of whatever was the problem.

I then added it into the array and it worked as before.

However, it still wasn't added when I rebooted.

...but, there is something different. Now, when I --examine /dev/sdi, it 
gives output for the whole array including 2 spares, which is the end 
result I expect :

 Active Devices : 6
Working Devices : 8
 Failed Devices : 0
  Spare Devices : 2

However, --detail /dev/md2 still denies /dev/sdi exists :

 Active Devices : 6
Working Devices : 7
 Failed Devices : 0
  Spare Devices : 1

What's up?

Max.

Re: trouble adding spare

[Justin Piszcz]

On Wed, 14 Jan 2009, Max Waterman wrote:

> Max Waterman wrote:
>>> 
>>> If that does not work, clean the drive out manually after removing it as a 
>>> spare from the array:
>>> dd if=/dev/zero of=/dev/sdi bs=1M
>> This is taking forever
> I stopped it after about half an hour, hoping that it had made garbage of 
> whatever was the problem.
>
> I then added it into the array and it worked as before.
>
> However, it still wasn't added when I rebooted.
>
> ...but, there is something different. Now, when I --examine /dev/sdi, it 
> gives output for the whole array including 2 spares, which is the end result 
> I expect :
>
> Active Devices : 6
> Working Devices : 8
> Failed Devices : 0
> Spare Devices : 2
>
> However, --detail /dev/md2 still denies /dev/sdi exists :
>
> Active Devices : 6
> Working Devices : 7
> Failed Devices : 0
> Spare Devices : 1
>
> What's up?
>
> Max.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

The superblock is at the end of the disk for 0.90.00 superblocks, so you 
would need to write to end of the disk or just let dd clear out the entire 
disk.  Honestly though that may not fix the root cause of the problem, we 
may need to wait for others on the list and/or Neil to check this one out. 
It seems very strange, can you post the regular output that people ask 
for so once they see your mail, they will have (hopefully) most of what 
they need to diagnose the problem.

1. mdadm -D /dev/mdX
2. cat /proc/mdstat
3. mdadm -Esvvv
4. uname -a

Justin.

Re: trouble adding spare

[Max Waterman]

Justin Piszcz wrote:
>
>
> On Wed, 14 Jan 2009, Max Waterman wrote:
>
>> Max Waterman wrote:
>>>>
>>>> If that does not work, clean the drive out manually after removing 
>>>> it as a spare from the array:
>>>> dd if=/dev/zero of=/dev/sdi bs=1M
>>> This is taking forever
>> I stopped it after about half an hour, hoping that it had made 
>> garbage of whatever was the problem.
>>
>> I then added it into the array and it worked as before.
>>
>> However, it still wasn't added when I rebooted.
>>
>> ...but, there is something different. Now, when I --examine /dev/sdi, 
>> it gives output for the whole array including 2 spares, which is the 
>> end result I expect :
>>
>> Active Devices : 6
>> Working Devices : 8
>> Failed Devices : 0
>> Spare Devices : 2
>>
>> However, --detail /dev/md2 still denies /dev/sdi exists :
>>
>> Active Devices : 6
>> Working Devices : 7
>> Failed Devices : 0
>> Spare Devices : 1
>>
>> What's up?
>>
>> Max.
>>
>> -- 
>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
> The superblock is at the end of the disk for 0.90.00 superblocks, so 
> you would need to write to end of the disk or just let dd clear out 
> the entire disk.  Honestly though that may not fix the root cause of 
> the problem, we may need to wait for others on the list and/or Neil to 
> check this one out. It seems very strange, can you post the regular 
> output that people ask for so once they see your mail, they will have 
> (hopefully) most of what they need to diagnose the problem.
>
> 1. mdadm -D /dev/mdX
> 2. cat /proc/mdstat
> 3. mdadm -Esvvv
> 4. uname -a
5. mdadm -E /dev/sdi

OK, I uploaded the output of the above commands to here :

<http://reality.sgiweb.org/maxw/tmp/md2Details/>

I hope someone can shed some light on this.

Thanks,

Max.

Re: trouble adding spare

[Max Waterman]

Can no one provide any enlightenment on this issue?

Max.

Max Waterman wrote:
> Justin Piszcz wrote:
>>
>>
>> On Wed, 14 Jan 2009, Max Waterman wrote:
>>
>>> Max Waterman wrote:
>>>>>
>>>>> If that does not work, clean the drive out manually after removing 
>>>>> it as a spare from the array:
>>>>> dd if=/dev/zero of=/dev/sdi bs=1M
>>>> This is taking forever
>>> I stopped it after about half an hour, hoping that it had made 
>>> garbage of whatever was the problem.
>>>
>>> I then added it into the array and it worked as before.
>>>
>>> However, it still wasn't added when I rebooted.
>>>
>>> ...but, there is something different. Now, when I --examine 
>>> /dev/sdi, it gives output for the whole array including 2 spares, 
>>> which is the end result I expect :
>>>
>>> Active Devices : 6
>>> Working Devices : 8
>>> Failed Devices : 0
>>> Spare Devices : 2
>>>
>>> However, --detail /dev/md2 still denies /dev/sdi exists :
>>>
>>> Active Devices : 6
>>> Working Devices : 7
>>> Failed Devices : 0
>>> Spare Devices : 1
>>>
>>> What's up?
>>>
>>> Max.
>>>
>>> -- 
>>> To unsubscribe from this list: send the line "unsubscribe 
>>> linux-raid" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
>> The superblock is at the end of the disk for 0.90.00 superblocks, so 
>> you would need to write to end of the disk or just let dd clear out 
>> the entire disk.  Honestly though that may not fix the root cause of 
>> the problem, we may need to wait for others on the list and/or Neil 
>> to check this one out. It seems very strange, can you post the 
>> regular output that people ask for so once they see your mail, they 
>> will have (hopefully) most of what they need to diagnose the problem.
>>
>> 1. mdadm -D /dev/mdX
>> 2. cat /proc/mdstat
>> 3. mdadm -Esvvv
>> 4. uname -a
> 5. mdadm -E /dev/sdi
>
> OK, I uploaded the output of the above commands to here :
>
> <http://reality.sgiweb.org/maxw/tmp/md2Details/>
>
> I hope someone can shed some light on this.
>
> Thanks,
>
> Max.
> -- 
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: trouble adding spare

[Max Waterman]

Someone else's post prompted me to try :

$ sudo /sbin/mdadm --detail --scan
ARRAY /dev/md2 level=raid5 num-devices=6 metadata=00.90 spares=2 
UUID=15bfec75:595ac793:0914f8ee:862effd8

and use that in mdadm.conf instead of the output of :

~$ sudo /sbin/mdadm --examine --scan
ARRAY /dev/md2 level=raid5 num-devices=6 
UUID=15bfec75:595ac793:0914f8ee:862effd8
   spares=2

This fixes my problem of the second spare drive not being added. I'm not 
sure why.

However, mdadm now gives me a 'message' :

mdadm: metadata format 00.90 unknown, ignored.

What's this about? Anything to worry about?

Max.
Max Waterman wrote:
> Can no one provide any enlightenment on this issue?
>
> Max.
>
> Max Waterman wrote:
>> Justin Piszcz wrote:
>>>
>>>
>>> On Wed, 14 Jan 2009, Max Waterman wrote:
>>>
>>>> Max Waterman wrote:
>>>>>>
>>>>>> If that does not work, clean the drive out manually after 
>>>>>> removing it as a spare from the array:
>>>>>> dd if=/dev/zero of=/dev/sdi bs=1M
>>>>> This is taking forever
>>>> I stopped it after about half an hour, hoping that it had made 
>>>> garbage of whatever was the problem.
>>>>
>>>> I then added it into the array and it worked as before.
>>>>
>>>> However, it still wasn't added when I rebooted.
>>>>
>>>> ...but, there is something different. Now, when I --examine 
>>>> /dev/sdi, it gives output for the whole array including 2 spares, 
>>>> which is the end result I expect :
>>>>
>>>> Active Devices : 6
>>>> Working Devices : 8
>>>> Failed Devices : 0
>>>> Spare Devices : 2
>>>>
>>>> However, --detail /dev/md2 still denies /dev/sdi exists :
>>>>
>>>> Active Devices : 6
>>>> Working Devices : 7
>>>> Failed Devices : 0
>>>> Spare Devices : 1
>>>>
>>>> What's up?
>>>>
>>>> Max.
>>>>
>>>> -- 
>>>> To unsubscribe from this list: send the line "unsubscribe 
>>>> linux-raid" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>>> The superblock is at the end of the disk for 0.90.00 superblocks, so 
>>> you would need to write to end of the disk or just let dd clear out 
>>> the entire disk.  Honestly though that may not fix the root cause of 
>>> the problem, we may need to wait for others on the list and/or Neil 
>>> to check this one out. It seems very strange, can you post the 
>>> regular output that people ask for so once they see your mail, they 
>>> will have (hopefully) most of what they need to diagnose the problem.
>>>
>>> 1. mdadm -D /dev/mdX
>>> 2. cat /proc/mdstat
>>> 3. mdadm -Esvvv
>>> 4. uname -a
>> 5. mdadm -E /dev/sdi
>>
>> OK, I uploaded the output of the above commands to here :
>>
>> <http://reality.sgiweb.org/maxw/tmp/md2Details/>
>>
>> I hope someone can shed some light on this.
>>
>> Thanks,
>>
>> Max.
>> -- 
>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
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Re: trouble adding spare

[Beolach]

On Wed, Jan 21, 2009 at 10:21 AM, Max Waterman
<davidmaxwaterman@fastmail.co.uk> wrote:
> Someone else's post prompted me to try :
>
> $ sudo /sbin/mdadm --detail --scan
> ARRAY /dev/md2 level=raid5 num-devices=6 metadata=00.90 spares=2
> UUID=15bfec75:595ac793:0914f8ee:862effd8
>
> and use that in mdadm.conf instead of the output of :
>
> ~$ sudo /sbin/mdadm --examine --scan
> ARRAY /dev/md2 level=raid5 num-devices=6
> UUID=15bfec75:595ac793:0914f8ee:862effd8
>  spares=2
>
> This fixes my problem of the second spare drive not being added. I'm not
> sure why.
>
> However, mdadm now gives me a 'message' :
>
> mdadm: metadata format 00.90 unknown, ignored.
>
> What's this about? Anything to worry about?
>

Change it to metadata=0.90 instead of metadata=00.90 & it should work
w/out the error message.  It would probably be good if mdadm.conf
and/or mdadm --detail --scan dropped leading zeros.


Conway S. Smith

Re: trouble adding spare

[Max Waterman]

Beolach wrote:
> On Wed, Jan 21, 2009 at 10:21 AM, Max Waterman
> <davidmaxwaterman@fastmail.co.uk> wrote:
>   
>> Someone else's post prompted me to try :
>>
>> $ sudo /sbin/mdadm --detail --scan
>> ARRAY /dev/md2 level=raid5 num-devices=6 metadata=00.90 spares=2
>> UUID=15bfec75:595ac793:0914f8ee:862effd8
>>
>> and use that in mdadm.conf instead of the output of :
>>
>> ~$ sudo /sbin/mdadm --examine --scan
>> ARRAY /dev/md2 level=raid5 num-devices=6
>> UUID=15bfec75:595ac793:0914f8ee:862effd8
>>  spares=2
>>
>> This fixes my problem of the second spare drive not being added. I'm not
>> sure why.
>>
>> However, mdadm now gives me a 'message' :
>>
>> mdadm: metadata format 00.90 unknown, ignored.
>>
>> What's this about? Anything to worry about?
>>
>>     
>
> Change it to metadata=0.90 instead of metadata=00.90 & it should work
> w/out the error message.  It would probably be good if mdadm.conf
> and/or mdadm --detail --scan dropped leading zeros.
>   
Yup, that fixed the error.

Any ideas why it didn't work with the output of --examine?

Max.