Re: Please Confirm I'm Solving Problem Correctly!

In a message dated 3/3/2004 11:11:54 PM Eastern Standard Time, 

bugzilla@watkins->home.com writes:

One failed drive should NOT cause data corruption!  The array should
continue just fine.  In most cases you may not know a disk has failed,
unless you notice a decrease in performance.

I am not an expert, so wait for someone like Neil Brown to respond before
you take any chances with your data.

Your "fail, remove and add" is correct, but only after you assemble the
array.  I would verify the data first, before doing the fail.

Corruption?  I have 2 guesses.
1. a bug in the RAID software.
2. somehow the bad disk was returning bad data instead of giving a read
error.  The RAID software did not detect a read error, so it did not fail
the drive.

Guy

I was looking back at some old comments from Neil Brown regarding another 
problem I once had.  I'm confused about whether I need to start the array with 
RUN before I "fail/remove" the bad drive? 

Right now, if I try to assemble the array with 

'mdadm -Av /dev/md6 --uuid=[uuid string] /dev/sd*' 

I get back a message: 
mdadm: /dev/md6 assembled from 4 drives - need all 5 to start it (use --run 
to insist)

If I 'cat /proc/mdstat' the array shows up but is "inactive". Which I guess 
means it isn't "started". But it seems to be "assembled". 

In the past, Neil told me to do just what it says, use "run".  Meaning, 
'mdadm -Av --run --uuid=[uuid string] /dev/sd*' 

Does the array in fact need to be "started" (with run, if necessary) before I 
can "fail" and "remove" the faulty drive? I guess that's my question? I 
thought it only needed to be "assembled".  

Hope I can get a good answer to this soon! Thanks. 

Andy Liebman