I recently had a motherboard go bad. I replaced it and as a result all my drives got plugged into a different sata socket (on the new MB). When I brought unraid back up it didn't automatically find my drives to be assigned, but it DID tell me the serial number of each drive for each slot. So I matched up the serial in say slot1 to the serial. All seemed good but with one caveat. ONE space didn't seem to recall what serial number should be there and had a "missing" listed. I also added a new hard drive so after assigning all the known drives to known slots I get slot2 as unassigned and two unused new drives.

 

I unplugged the drive that I am 80pct certain is the new drive to take that out of the mix. Apon a reboot, I assigned the remaining drive to the unassigned slot2. I then must either mount the array (clicking the Yes I am sure I want to do this check box) or I have an option to Restore (again clicking the yes I am sure check box).

 

Which do I do that will give me the most probability of keeping all my data... it would be REALLY bad to lose all my data.

I recently had a motherboard go bad. I replaced it and as a result all my drives got plugged into a different sata socket (on the new MB). When I brought unraid back up it didn't automatically find my drives to be assigned, but it DID tell me the serial number of each drive for each slot. So I matched up the serial in say slot1 to the serial. All seemed good but with one caveat. ONE space didn't seem to recall what serial number should be there and had a "missing" listed. I also added a new hard drive so after assigning all the known drives to known slots I get slot2 as unassigned and two unused new drives.

 

I unplugged the drive that I am 80pct certain is the new drive to take that out of the mix. Apon a reboot, I assigned the remaining drive to the unassigned slot2. I then must either mount the array (clicking the Yes I am sure I want to do this check box) or I have an option to Restore (again clicking the yes I am sure check box).

 

Which do I do that will give me the most probability of keeping all my data... it would be REALLY bad to lose all my data.

Easiest way to NOT lose data is to NOT accidentally assign a data drive as the parity drive.

Easiest way to do that is to initially NOT assign a parity drive at all. 

 

Since you've lost track of which drive is which, assign ONLY the data drives.  Do NOT assign any new drives that were not previously a part of the array unless you are absolutely certain that when it shows as "unformatted" you will not be surprised.

 

Since you are setting a new disk configuration (new motherboard, new disk controllers) you will want to use the button labeled as "restore"  It has NOTHING to do with recovering data, or restoring data, it just sets a new disk configuration and resets the status of your array to a point BEFORE and parity was calculated.  PRessing it immediately invalidates parity.

 

After assigning ONLY data drives, and pressing "restore" and starting the array you should be able to see all of your data drives online.  If any drive shows as "unformatted" and it is not a new drive (one you just decided to add since the box was all disassembled), and it is not one of your smaller drives, it is likely to be your old parity drive.

 

Just stop the array, re-asign the drive you originally was parity to the data slot, leave the parity disk un-assigned, and start the array once more.  When you get all the disks back mounted, and where they all have data shared on the lan, then you can stop the array once more and finally assign the parity drive.

 

After assigning the parity drive and subsequently starting the array a full parity calculation will begin.  Let it finish.

 

As long as you do not assign a data drive as parity you should not lose data.  So... like I said above, do not initially assign ANY parity drive until you see all the data drives and your data.  When leaving the parity drive un-assigned you must press the button labeled "restore" to set a new disk configuration.

 

Joe L

Joe's method is probably simpler and faster, but if worse comes to worse, this will also work:

 

You can take each drive and one-by-one hook it up to a Linux computer.  The computer should be able to read all of your data drives and display your files (since the data drives use the standard ReiserFS).  However, the computer will not be able to read/display your parity drive, since it has no file system.

 

I believe you can also accomplish this on a Windows computer if you first install a tool like YAReG, which allows Windows to read ReiserFS.

 

The lesson to take away from this is to not try to do two things at once - you should always make major changes to your server (such as replacing the mobo or adding a drive) one-at-a-time.

You can take each drive and one-by-one hook it up to a Linux computer.  The computer should be able to read all of your data drives and display your files (since the data drives use the standard ReiserFS).  However, the computer will not be able to read/display your parity drive, since it has no file system.

Well, your unRAID computer is a Linux computer, isn't it?  So why would you need to go to another Linux computer?

On your unRAID computer you can mount your disks the same way, and display your files, right?

 

I believe you can also accomplish this on a Windows computer if you first install a tool like YAReG, which allows Windows to read ReiserFS.

Why would you want to trust your disks to a Windows computer?  That vicious OS can do nasty things to you without notice!

 

You can take each drive and one-by-one hook it up to a Linux computer.  The computer should be able to read all of your data drives and display your files (since the data drives use the standard ReiserFS).  However, the computer will not be able to read/display your parity drive, since it has no file system.

Well, your unRAID computer is a Linux computer, isn't it?  So why would you need to go to another Linux computer?

On your unRAID computer you can mount your disks the same way, and display your files, right?

True, and that's something I was thinking about when I posted that, but I wasn't sure about a few things.  To temporarily convert an unRAID server into a full-blown Linux computer for the purposes of data recovery, wouldn't you need to dedicate a hard drive to the Linux install?  Or flash drive, or something else.  Still, none of unRAID's drives could be used for this purpose, except maybe the cache drive, correct?  Doing so would cause further data loss.

 

I believe you can also accomplish this on a Windows computer if you first install a tool like YAReG, which allows Windows to read ReiserFS.

Why would you want to trust your disks to a Windows computer?  That vicious OS can do nasty things to you without notice!

Really?  Are you saying that hooking up an unRAID data disk to a Windows computer running YAReG or similar could lead to data loss?  I've never tried it, but I always thought it was an option in a worst-case scenario.

I believe you can also accomplish this on a Windows computer if you first install a tool like YAReG, which allows Windows to read ReiserFS.

Why would you want to trust your disks to a Windows computer?  That vicious OS can do nasty things to you without notice!

Really?

Really!

I don't trust windows for s*it.

You can take each drive and one-by-one hook it up to a Linux computer.  The computer should be able to read all of your data drives and display your files (since the data drives use the standard ReiserFS).  However, the computer will not be able to read/display your parity drive, since it has no file system.

Well, your unRAID computer is a Linux computer, isn't it?  So why would you need to go to another Linux computer?

On your unRAID computer you can mount your disks the same way, and display your files, right?

True, and that's something I was thinking about when I posted that, but I wasn't sure about a few things.  To temporarily convert an unRAID server into a full-blown Linux computer for the purposes of data recovery...

I am trying hard to imagine just what exactly data recovery you are talking about, that you would need a "full-blown" Linux.

 

... wouldn't you need to dedicate a hard drive to the Linux install?  Or flash drive, or something else.  Still, none of unRAID's drives could be used for this purpose...

Since you are a really nice guy, (though you always like to contradict me  ), let me show you a really cool trick:

1. Unzip the file memdisk which you'll see attached at the end of this post, and put it on your unRAID flash key.

2. Get the iso image of your favorite "full-blown" recovery Linux distro. (For example, take Parted Magic, it's only 70mb). Unzip it, and put the iso on your unRAID flash key.

3. Add the following three lines to your syslinux.cfg:

label Parted Magic (Live CD)
kernel memdisk
append iso initrd=pmagic-4.8.iso

Now reboot your server.  Notice that you'll have one additional item in your boot menu. Select it and see what happens. 

Notice also that we didn't burn the iso file to a CD, nor did we use any specially prepared USB flash key.

We didn't modify any Master Boot Records, we didn't touch any partitions in any way.

 

And for when you're done screaming and jumping with excitement, here's a little homework assignment for you:

Imagine you have an old windows 2k/xp computer which doesn't have any floppy drive, doesn't have a cdrom drive, and can't boot from usb. It has a network connection, but it doesn't have the proper equipment to do a network boot. Its only windows partition is almost full to the brink. You have lots of precious junk on it, accumulated over the years. You wish you could somehow boot that box into Linux, run a memtest, check the SMART status of that old hard disk, and maybe make an exact image of its windows partition to a safe place. You don't want to install any new ".exe" on it, nor modify the MBR. (you don't want to mess up the windows installation that's on it).  Can you think of a way of doing it without taking the box apart?

 

Yours,

Purko

memdisk.zip