[UU_] Won't go away

[UU_] Won't go away

[Michael Munger]

It's my understanding, that an array running with [UU_] is degraded and
there is a disk problem.

I have been trying to create a RAID array using this command:

mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdb1
/dev/sdc1 /dev/sdd1

However, once it create it, it get this in /proc/mdstat:

Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd1[3] sdc1[1] sdb1[0]
      3906764800 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2]
[UU_]
      [>....................]  recovery =  0.1% (2611780/1953382400)
finish=1737.7min speed=18709K/sec
      bitmap: 0/15 pages [0KB], 65536KB chunk

I have done the following to "fix" the drive:

1. Smartmontools smartctl long and short tests. All passed.
2. Zeroed the first 1GB of the drive (overkill, I know I could just do
the first 512) with dd if=/dev/zero of=/dev/sdb count=250000 bs=4k
3. Re-partitioned the drive.
4. Re-create.

No joy.

Then, I swapped this hard drive out for another drive.

I am still getting [UU_].

Thoughts?
-- 
Michael Munger, dCAP, MCPS, MCNPS, MBSS
High Powered Help, Inc.
Microsoft Certified Professional
Microsoft Certified Small Business Specialist
Digium Certified Asterisk Professional
michael@highpoweredhelp.com

-- 
Michael Munger, dCAP, MCPS, MCNPS, MBSS
High Powered Help, Inc.
Microsoft Certified Professional
Microsoft Certified Small Business Specialist
Digium Certified Asterisk Professional
michael@highpoweredhelp.com

Re: [UU_] Won't go away

[Phil Turmel]

On 10/27/2015 08:17 AM, Michael Munger wrote:
> It's my understanding, that an array running with [UU_] is degraded and
> there is a disk problem.
> 
> I have been trying to create a RAID array using this command:
> 
> mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdb1
> /dev/sdc1 /dev/sdd1
> 
> However, once it create it, it get this in /proc/mdstat:
> 
> Personalities : [raid6] [raid5] [raid4]
> md0 : active raid5 sdd1[3] sdc1[1] sdb1[0]
>       3906764800 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2]
> [UU_]
>       [>....................]  recovery =  0.1% (2611780/1953382400)
> finish=1737.7min speed=18709K/sec
>       bitmap: 0/15 pages [0KB], 65536KB chunk

What's to fix?  Did you try waiting for the recovery to finish?
Creating an array generally isn't instant -- the redundancy has to be
computed over the entire array.

Now, you might have speed limits that are making it slower than possible
(see man md), but multiple hours on big devices is perfectly normal.

Phil

Re: [UU_] Won't go away

[Robin Hill]

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On Tue Oct 27, 2015 at 08:17:26AM -0400, Michael Munger wrote:

> It's my understanding, that an array running with [UU_] is degraded and
> there is a disk problem.
> 
> I have been trying to create a RAID array using this command:
> 
> mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdb1
> /dev/sdc1 /dev/sdd1
> 
> However, once it create it, it get this in /proc/mdstat:
> 
> Personalities : [raid6] [raid5] [raid4]
> md0 : active raid5 sdd1[3] sdc1[1] sdb1[0]
>       3906764800 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2]
> [UU_]
>       [>....................]  recovery =  0.1% (2611780/1953382400)
> finish=1737.7min speed=18709K/sec
>       bitmap: 0/15 pages [0KB], 65536KB chunk
> 
> I have done the following to "fix" the drive:
> 
> 1. Smartmontools smartctl long and short tests. All passed.
> 2. Zeroed the first 1GB of the drive (overkill, I know I could just do
> the first 512) with dd if=/dev/zero of=/dev/sdb count=250000 bs=4k
> 3. Re-partitioned the drive.
> 4. Re-create.
> 
> No joy.
> 
> Then, I swapped this hard drive out for another drive.
> 
> I am still getting [UU_].
> 
> Thoughts?

This is perfectly normal. A RAID-5 array is created in degraded mode,
then the final disk is synchronised. This makes the array available
immediately, with the synchonisation happening in the background.

Just leave it to complete the recovery process.

Cheers,
    Robin
-- 
     ___        
    ( ' }     |       Robin Hill        <robin@robinhill.me.uk> |
   / / )      | Little Jim says ....                            |
  // !!       |      "He fallen in de water !!"                 |

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Re: [UU_] Won't go away

[Phil Turmel]

Hi Michael,

{Added the list back and fixed the top-posting.  Convention on
kernel.org is to reply-to-all, trim replies, and bottom post or interleave.}

On 10/27/2015 08:28 AM, Michael Munger wrote:
> On 10/27/2015 08:23 AM, Phil Turmel wrote:
>> On 10/27/2015 08:17 AM, Michael Munger wrote:

>>> Personalities : [raid6] [raid5] [raid4]
>>> md0 : active raid5 sdd1[3] sdc1[1] sdb1[0]
>>>       3906764800 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2]
>>> [UU_]
>>>       [>....................]  recovery =  0.1% (2611780/1953382400)
>>> finish=1737.7min speed=18709K/sec
>>>       bitmap: 0/15 pages [0KB], 65536KB chunk

>> What's to fix?  Did you try waiting for the recovery to finish?
>> Creating an array generally isn't instant -- the redundancy has to be
>> computed over the entire array.
>>
>> Now, you might have speed limits that are making it slower than possible
>> (see man md), but multiple hours on big devices is perfectly normal.

> I thought [UU_] indicated a physical drive problem, not logical array
> issue. I'll wait until 2pm when this is supposed to finish and re-check.

I mentioned the speed limits because 20MB/sec is kinda low for modern
drives.  You can probably speed that up.

> It will be GREAT if that's all it was... my being impatient!
>
> PS... lsdrv is a great utility. thanks for making it available on Github.

You're welcome :-)

Phil