Power lost during initial format

 

I lost power partway through the initial format before the parity sync/clear.  When I brought the machine up again it restarted the parity sync/clear from the begining.  Eventually that finished and the disk was available but was not writable.  I restarted the array, restarted the machine, etc. but the disk would not write.  It was my first disk to add to the array (and my first time using UnRaid).

 

Example log when trying to add a share:

 

Jan 24 09:51:19 Storage emhttp: shcmd (14): mkdir '/mnt/user/Movies'

Jan 24 09:51:19 Storage shfs: shfs_mkdir: mkdir: /mnt/disk1/Movies (30) Read-only file system

Jan 24 09:51:19 Storage emhttp: _shcmd: shcmd (14): exit status: 1

Jan 24 09:51:19 Storage emhttp: shcmd (15): chmod 700 '/mnt/user/Movies'

Jan 24 09:51:19 Storage emhttp: _shcmd: shcmd (15): exit status: 1

Jan 24 09:51:19 Storage emhttp: shcmd (16): rm /etc/samba/smb-shares.conf >/dev/null 2>&1

Jan 24 09:51:19 Storage emhttp: shcmd (17): cp /etc/exports- /etc/exports

Jan 24 09:51:19 Storage emhttp: shcmd (18): echo \"/mnt/disk1\" '-async,no_subtree_check,anongid=0,anonuid=0,all_squash' 'Disks' >>/etc/exports

Jan 24 09:51:19 Storage emhttp: shcmd (19): killall -HUP smbd

Jan 24 09:51:19 Storage emhttp: shcmd (20): /etc/rc.d/rc.nfsd restart | logger

Jan 24 09:51:19 Storage mountd[1313]: Caught signal 15, un-registering and exiting.

Jan 24 09:51:20 Storage kernel: nfsd: last server has exited, flushing export cache

 

 

I then logged in, with the array still running, and ran reiserfs to format the drive.  Both the data disk and the parity disk were written to.  I restarted the array.  The disk is now writable; I can create shares, etc.  Everything seems to be working properly.

 

My question - is the disk actually protected by the parity disk?  It seems to be writing to both disks when I write to it. 

That's how unraid works.  The data has to be available in two places if it is to be able to recover if a drive is lost.

Yes, I am hoping that the fact that both the data and parity disk are written is a good sign.  My concern is due to this thread:

 

http://lime-technology.com/forum/index.php?topic=2817

 

After doing the above, I found this comment in the above thread:

 

"Do NOT format the drive on your own using a reiserfs linux command, or using a button in unMENU, if you do, the pre-clear will be invalid, and you may even fool unRAID into thinking it is cleared when it is not."

 

This comment is in relation to pre-clear, so not exactly the same, but I'm still wondering if I did the right thing.

My concern is due to this thread:

 

http://lime-technology.com/forum/index.php?topic=2817

 

After doing the above, I found this comment in the above thread:

 

"Do NOT format the drive on your own using a reiserfs linux command

 

Normally, you should NOT format the drive on your own.

You assign it to the array, and let unRAID format it the way it likes it.

 

 

Agreed.  I ended up formatting it because I was not able to find another solution.  The drive was showing up but was not writable (and I had not read the link I posted above yet).  Once I formatted it started to work properly.

Normally, you should NOT format the drive on your own.

You assign it to the array, and let unRAID format it the way it likes it.

More accurately, you should use the "Format" button on the management console to format any newly added drive.  unRAID will not format any disk on its own unless you press that button.

 

Do not use a linux command line command to format a pre-cleared drive, as it does not set the file-system type in the MBR as unRAID expects it.       

 

The harm will come when you start the array it will not start calculating parity as it will still think the drive is completely zero (since it still has a pre-clear signature)

 

Joe L.

Thanks

 

The problem I had was that there was no format button.  For whatever reason, because the format had started (but was then interrupted by the power failure) the disk went through the parity sync and everything was showing green --- except that I could not write to the disk.  Once I did the format I was able to write to the disk.

 

So it all seems to be working now - but given the comments I found I wonder if it is actually working.

 

Is there a reliable way to check?

Should I start over?  If so, how?

One more clarification - this was not a precleared drive.  I put a fresh disk in, started the format - lost power - restarted - continued the process - got online ---- and then was unable to write to the disk.

To be sure, just press the "check" button to find/fix any parity that might not have been calculated. (Unless it went through a full parity check since you formatted the disk)

Great - I will do that.  Thank you!

 

So it all seems to be working now - but given the comments I found I wonder if it is actually working.

 

Is there a reliable way to check?

Should I start over?  If so, how?

 

 

It's up to you.  But here is what I would do if I were you:

Instead of wondering, run the new disk through the standard procedure.

-- Unassign it from your array.

-- Press the Restore button to let unRAID rebuild parity with the old disks.

-- Run one or two cycles of preclear on your new disk.  This will give you peace of mind.

-- Assign the newly precleared disk to the array. It will show as unformatted.

-- Press the format button on the web-management page.

Done.

 

This preclear_disk.sh script gives the new disk a really good workout,

and helps you catch bad disks that you should RMA right away.

 

That's my personal preference.