Topic: RAID help

[smeusr]

Hi, I just checked the health of my mirrored drives from the console and I got the following read out.

-----------------------------------------
Personalities : [raid1]
md2 : active raid1 sdb2[1]
      312464128 blocks [2/1] [_U]

md1 : active raid1 sda1[0] sdb1[1]
      104320 blocks [2/2] [UU]

unused devices: <none>

Only some of the RAID devices are unclean.

Manual intervention may be required.
----------------------------------------------------
I've also just checked my admin system emails and found the following message.

"A DegradedArray event has been detected on md device /dev/md2"

How can I find out which drive this is?  How do I know when I'm in trouble?  Besides a catastrophic failure? 

--------------------------------------------------------


I'm noob when it gets this technical.  Please help.

Thank you.

p.s. I've searched for all combinations of key words and have not found a similar problem reported by someone else.

[Stefano]

Hi, I just checked the health of my mirrored drives from the console and I got the following read out.

-----------------------------------------
Personalities : [raid1]
md2 : active raid1 sdb2[1]
      312464128 blocks [2/1] [_U]

md1 : active raid1 sda1[0] sdb1[1]
      104320 blocks [2/2] [UU]

unused devices: <none>

ok..

try to re-add sda2 to the array with

Code: [Select]

mdadm -a /dev/md2 /dev/sda2

and monitor the array with

Code: [Select]

cat /proc/mdstat

if something goes wrong you'll see the reconstruction restart again; in this case, buy another hd

Ciao
Stefano

[smeusr]

Thanks Stephano for the quick response.

I did as you said.  The drive is now going through recovery so I'm guessing that is the same as reconstruction as you noted above.  Is there a quick way to figure out which drive is sda2 as attached to which cable?  I've also had this setup for a couple of years so I might not be able to get the exact drive to replace the faulty one.  Is there a way to rebuild onto a new set of drives short of rebuilding a new set from scratch?

Thanks very much again and much appreciate it.

[Stefano]

I did as you said.  The drive is now going through recovery so I'm guessing that is the same as reconstruction as you noted above. 

yes

Is there a quick way to figure out which drive is sda2 as attached to which cable? 

you'd have sata port1 and port2.. sda should be on port1

I've also had this setup for a couple of years so I might not be able to get the exact drive to replace the faulty one.

you need a new disk at least of the same dimension.. if it's bigger, no problem

  Is there a way to rebuild onto a new set of drives short of rebuilding a new set from scratch?

yes, reading the documentation in the wiki

Ciao
Stefano

[janet]

smeusr

There is a lot of useful information on the wiki pages.
Please read the
FAQ at
http://wiki.contribs.org/SME_Server:Documentation:FAQ
& quite a few of the Howtos at
http://wiki.contribs.org/Category:Howto
etc before asking, as your questions may have already been answered.

Is there a way to rebuild onto a new set of drives short of rebuilding a new set from scratch?

You can fit a larger capacity drive, and the system will resync the new drive  based on the smaller drive size.
Alternatively upgrade the RAID array to fully utilise newer larger hard drives:
http://wiki.contribs.org/Raid#Upgrading_the_Hard_Drive_Size

Is there a quick way to figure out which drive is sda2 as attached to which cable?

The first physical SATA port will be sda, the second sdb & so on. Your motherboard should be labelled accordingly.
Alternatively the drive serial numbers and sata ports can be correlated using commands in
http://wiki.contribs.org/Monitor_Disk_Health
ie
smartctl -a /dev/sda
smartctl -a /dev/sdb

[smeusr]

Mary, Stephano,

You guys are fantastic.  Thanks so much for all your guidance.

I just checked my drive after the rebuild and it is reading as follows.

--------------------
root@smesvr ~]# cat /proc/mdstat
Personalities : [raid1]
md2 : active raid1 sda2[0] sdb2[1]
      312464128 blocks [2/2] [UU]

md1 : active raid1 sda1[0] sdb1[1]
      104320 blocks [2/2] [UU]

unused devices: <none>

--------------------

They both have two [UU].  Does that mean that the drive is 'ok'?  I just checked the server console and it says that all the drives are in a clean state.  Should I still consider replacing drives? 

I will definite study the links and references to prepare myself further.

Thank you again.

[smeusr]

I haven't been back to the Contribs.org site recently and never knew the FAQ is so packed full of information.   

FANTASTIC...

[janet]

smeusr

the FAQ is so packed full of information....FANTASTIC...

Yes, a lot of people have done a lot of good work, and we should all be thankfull to them.
They know who they are, and anyway you can check the History pages to see who authored various articles.