RAID 1

RAID 1

[Dean Carrera]

Is there a command I can use to check the health of the software RAID 1
that I am running. Any command to check the health of the individual
disks?


Thanks... 

Dean C
(770)-857-4703 
  
  
  
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Re: RAID 1

[Marshall Lake]

> Is there a command I can use to check the health of the software RAID 1
> that I am running. Any command to check the health of the individual
> disks?

I'm not sure what to recommend but I know what NOT to recommend.  An
article concerning the software package named "S.M.A.R.T. Monitoring
Tools" appeared in Linux Journal a few months back.  (Actually I'm not
sure if S.M.A.R.T. works with RAID disks.)  This package purported to
analyze and monitor the health of hard drives.  I ran S.M.A.R.T. on the
hard drive of one of my systems.  Afterwards I had to reformat the hard
drive and reinstall the system in order to get it running again.  I
contacted the author and it was his opinion that I did something wrong.
Even if I did do something wrong the software should not corrupt my hard
drive the way it did.

-- 
Marshall Lake -- mlake@mlake.net -- http://mlake.net

Re: RAID 1

[Matt Howard]

Marshall Lake wrote:
> I'm not sure what to recommend but I know what NOT to recommend.  An
> article concerning the software package named "S.M.A.R.T. Monitoring
> Tools" appeared in Linux Journal a few months back.  (Actually I'm not
> sure if S.M.A.R.T. works with RAID disks.)  This package purported to
> analyze and monitor the health of hard drives.  I ran S.M.A.R.T. on
> the
> hard drive of one of my systems.  Afterwards I had to reformat the
> hard
> drive and reinstall the system in order to get it running again.  I
> contacted the author and it was his opinion that I did something
> wrong. Even if I did do something wrong the software should not
> corrupt my hard drive the way it did.

Yes, SMART is something that can cause problems -- when it was new, many
systems couldn't boot the disks with it on.  For new drives, OTOH, it
can warn you of impending doom.  SMART is very iffy though.

Back to the OP's question:  you can "cat /proc/mdstat" for a quick
overview of raid health.  Also, you can use the "mdadm" tool to monitor
your arrays, and email you if one goes faulty.  (Also, the md driver
will send kernel log messages if an array's state changes.)

I would recommend testing the smart tool on a similar drive.  Do a
"sync" before trying, I have seen old drives that stop when they
receive the SMART commands.  DO NOT USE ANY OF THE SMART TEST
OPTIONS!!! Some disks will read-test, while others will
read/write-test.

A good plan would be to have mdadm monitor your raid, and smartd monitor
your disks.  Are you forwarding syslog to a central logging server? 
Grep the logs for warnings from md.

-- 
Matt Howard <mhoward@sigins.com>
Superior Insurance - Technical Services

Re: RAID 1

[Matt Howard]

On Friday 14 May 2004 03:25 am, you wrote:
> Hello,
>
>  I didnt know about this mdadm tool instead of using raidtools. I
> already have a production system using raidtools. Can I just remove
> raidtools and install mdadm instead with no harm in my system? I
> would like to receive an email in the case the raid state changes...
>
>  Thanks in advance and sorry for my english
>
>  Miguel
>

They'll even work fine together.  They're both different takes on 
managing the md system -- raidtools being many separate tools, mdadm 
being one single tool.  They both use the same system calls to manage 
the raid (but different config files!).  If you simply install mdadm, 
you don't necessarily have to use it for *all* raid management;  I add 
it to Slackware boxes simply for the monitoring.  Getting monitoring 
for all arrays is as simple as adding these two lines to your rc.local 
(or equivalent boot script):

echo "Enabling RAID Monitor."
/sbin/mdadm -F --scan -m foo@barco.net -f

-- 
Matt Howard <mhoward@sigins.com> 317-259-6472
Technical Services - Superior Insurance

Re: RAID 1

[Pau Montero Pares]

Dean Carrera wrote:

> Is there a command I can use to check the health of the software RAID 1
> that I am running. Any command to check the health of the individual
> disks?

	Look at http://www.samag.com/documents/s=9102/sam0404a/0404a.htm

   if ( open( F, "/proc/mdstat" ) ) {
     print "RAID detected: ";
     @file = <F>;
     if ( / \[(\d)\/(\d)\] / && $2 ne $1 ) {
       print "NOT OK\n";
     } else {
       print "OK\n";
     }
   }

	You can use a bit of perl to detect mdstat errors. Hope it helps.

-- 
Pau Montero Parés
http://www.imente.com
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Re: RAID 1

[Luca Ferrari]

On Thursday 13 May 2004 20:28 Dean Carrera's cat walking on the keyboard  
wrote:

> Is there a command I can use to check the health of the software RAID 1
> that I am running. Any command to check the health of the individual
> disks?
>
 

Have a look to /proc/mdstat and search for _

Luca

-- 
Luca Ferrari,
fluca1978@virgilio.it
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