Hi,

 

I'm currently setting up my unRAID server for the 1st time. I built a computer and got a new 3TB HDD for Parity.

 

I am following this guide: http://lime-technology.com/wiki/index.php/Configuration_Tutorial#Add_Drives_to_the_Array

and I've gotten to the step of adding hard drives to the array.

 

My existing data sits on 3 HDDs. A single 1TB HDD and two 2TB HDDs, so I plan to start with a total of 5TB of space along with a parity drive of 3TB.

 

All of my existing HDDs are relatively full with only around 100-200GBs left on each. Because of this and the fact that these have proven to be reliable drives, I wanted to skip preclear on these 3 HDDs. I did run preclear on my brand new 3TB parity drive 2 times.

 

I then installed all of the drives and started following the steps on the guide. It said you can only add disks which already have data on the initial setup.

"Adding drives to the array is simply a matter of telling UnRAID which drive to place where during initial setup. Later as you add drives to the array after enabling a parity drive, each drive must have zeros written to every sector before the drive is accepted into the array."

So I followed the steps of adding a drive. I went to the main page of the web GUI and choose my 3 disks as Disk1, 2, & 3. I did not assign my parity drive yet. I then hit start and all of my HDDs showed their size, but also showed as unformatted. The guide doesn't mention any special requirements for these drives that I'm not preclearing, but they've come out of a windows machine and are formatted as NTFS.

 

Anything I'm reading about this talks about either copying the data and preclearing the drives or mounting as external NTFS with unMenu. Is there any other way I can make this work without copying all of my data? Without somehow copying it to my precleared parity drive, I don't have the capacity to do this. I can't believe this isn't something that is extremely common and spoken to in the guide or more easily found by searching the forums?

 

Just to be clear, I have not done any type of format of these drives with existing data. But just to be sure, is my data at risk from anything I've done? I can't imagine if it sees the disks as unformatted that it would do anything to my existing data without me prompting it.

 

Lastly, if I do need to copy data over somehow, what is the proper way for me to remove these drives safely from unRAID? If I stop the array it does not let me assign these disks as "unassigned" again.

 

Any help is much appreciated!

So as a follow-up to this, I took powered down the unRAID server, pulled one of the 2TB hard drives and put it back on a Windows machine and it's shwoing with no filesystem. it shows an NTFS partition, but windows Disk Management will only allow me to delete the volume. It won't let me assign a drive letter or read from the drive.

 

Any ideas why this would happen?

You cannot use disks in unRAID that already contain data without losing it unless they have previously been used by unRAID and formatted by unRAID.  If a disk has not already been used by unRAID, then adding it to unRAID re-writes the partition table and clears it down. 

 

The purpose of a pre-clear is two-fold:

- It provides a check that a sector has no bad sectors as if it does it is unsuitable for use in unRAID.

- It avoids the array being down for a long time when adding to an existing array.

 

You can avoid the pre-clear (although it is still a good idea) when first setting up an array as at that point unRAID is not trying to maintain parity so can simply reformat the disks for its own use.

 

So are you saying that simply by choosing these hard drives and starting unraid (no parity drive chosen though), that it re-wrote the partition table and cleared them even without me choosing the format option?

 

So are you saying that simply by choosing these hard drives and starting unraid (no parity drive chosen though), that it re-wrote the partition table and cleared them even without me choosing the format option?

Not sure.  You certainly did not reformat the disk, but I am not sure if the partition table was rewritten or not at that point.  Maybe someone else can chime in and confirm this?  You could also use fdisk from a telnet session in unRAID to see what the partition table (and partition type) is set to.

So are you saying that simply by choosing these hard drives and starting unraid (no parity drive chosen though), that it re-wrote the partition table and cleared them even without me choosing the format option?

Not sure.  You certainly did not reformat the disk, but I am not sure if the partition table was rewritten or not at that point.  Maybe someone else can chime in and confirm this?  You could also use fdisk from a telnet session in unRAID to see what the partition table (and partition type) is set to.

 

Thank you very much for your help. Your tip on the re-written partition table lead me to a solution!

 

I was able to use testdisk to re-write the partitions and have access to the hard drives. I guess I will now figure something out to transfer data and preclear all drives before I start.

 

I do really think the guide should be updated to mention the restrictions around the hard drives with already existing data.

 

Thank you for your help!

So are you saying that simply by choosing these hard drives and starting unraid (no parity drive chosen though), that it re-wrote the partition table and cleared them even without me choosing the format option?

No, it did not "format" them, but it did change the MBR to put into place the partition needed by the unRAID file-system.  (in other words, the first 512 bytes on the disk have been re-written)  In addition, the one byte on the MBR that indicates its first partition "type" has been changed from indicating an NTFS file system to a value indicating it is a LINUX file system.  That is why Windows no longer recognizes it.  Only way to get to the data now is with a windows data recovery tool, or to restore the MBR to how it was prior to assigning them to the array.

 

Anybody can edit the wiki (all but the official wiki section)

I just added this line to the section you were following:

Disks that do not have unRAID compatible partitions will be re-partitioned immediately

upon assignment to the array. (In other words, do not assign disks from other OS with data you wish to retain)

 

Joe L.

 

Fortunately you didn't format the drives -- and have apparently already reset the MBR so you can see the data okay.

 

What you should do here is add at least one additional data drive -- I'd get another 3TB drive and just add it as the only data drive along with your parity drive;  then copy all the data from one of your 2TB drives to the array;  then add that 2TB drive to the array;  and then copy all the data from your other 2 drives.    Then you can add them as well.    This will give your array a bit of "breathing room", since your current drives are already fairly full -- you'll have all of your data plus 3+TB of free space available.

 

If you REALLY don't want to buy another drive (NOT a good idea);  you could unassign the parity drive and assign it as a data drive -- so your array would have one drive and no parity;  then copy 3TB of data to it (from your 1TB and 2TB drives);  then add those drives to the array;  then copy all the data from your other 2TB drive to the 2TB drive in the array;  then add that last 2TB drive to the array;  then copy all of the data from the 3TB drive to the 1TB and 2nd 2TB drive (so the 3TB drive is now empty);  then remove the 3TB drive from the array and assign it as parity.    This involves a LOT of copying -- and you end up with array that's nearly full ... so adding an additional 3TB drive (as I suggested above) is a MUCH better idea.

 

Thanks for all of your help. I spent last weekend transferring files around after freeing up some space. I then ran preclear on all drives and was able to get everything up and running!

 

I ended up using testdisk to manually put the NTFS partition tables back on and all my data was still there thank God.

 

I appreciate you updating the wiki and your help!