Hey guys,

 

  My (homemade) linux NAS currently uses linux software raid5 for storage. My question is pretty simple (or is it?); does unRAID support software raid arrays out of the box?

 

  If it does, I could put in a couple of new drives which total size is greater than the space used by my current data on the linux raid, boot my current box with unRAID, configure the new drives in unRAID, move the files from the old /dev/md0 to the new unRAID drives, and then destroy then raid array and add the old drives to the unRAID array... Hope you didn't get lost in that procedure

 

  So, what do you think? Thanks!

Hey guys,

 

   My (homemade) linux NAS currently uses linux software raid5 for storage. My question is pretty simple (or is it?); does unRAID support software raid arrays out of the box?

Sorry, but the answer is "no" It does not.

 

However, you could do something like you described, but in reverse.

 

You could install the new drives in your existing server, boot it up with unRAID, but do not initally assign any drives to the unRAID array.  Instead, download and use the "preclear_disk.sh script to clear the new drives (and format them).  This will also give you some confidence in the new drives.      Then, you can assign each of the new drives to the unRAID array and press the "Format" button on the new drives, This will create a reiserfs file-system on each of them.  You do not need to assign a parity drive for this initial formatting of the new drives.

 

As long as you do not assign any of your existing "software raid" drives to the unRAID array, it will not touch them or affect their contents in any way. So... be absolutely certain which devices you preclear, making certain by their model/serial number they are the ones you intend to clear.   Or, if you want to be absolutely certain, unplug your existing "software array"  drives while you perform these first steps of preparing the new drives with their file-systems under unRAID.  Or, do them on another box.. It can be done on another, then after the new drives are formatted and have unRAID compatible file-systems, they can be moved to your old server.

 

The reason I am asking you to partition and format the drives using unRAID is they will subsequently be recognized as compatible when assigned to an unRAID array.  The data on them will not be erased, and they will only need the parity calc step performed.

 

Assuming you followed this, booting back on your old OS, you will now have your old software array intact in your old server and you will have the new disk drives in it as well, each new disk formatted with their new reiserfs file-systems.   Odds are very high your existing server will be able to mount those outside of its array.  (You do not want the new drives as part of your old "software raid")

 

OK, getting close.... copy your data from the existing array to the new data drives using your old OS.  These new data drives will each have their own file system, so you can mount them anywhere you like for this step.  Each top level directory on the new drives will become a user-share on the LAN, so you can organize your files as needed.  If you have two data drive you can make a "movies" folder on both, put half of your movies on each, and when under unRAID their combined contents will be present as a single "user-share"

 

Create a few top-level folders on the new data drives, as you will eventually want to see as shared "folders" on the LAN, and copy the data as needed.

 

OK, now you can shut down, boot up on unRAID, and assign the new data drives to its array.  You can also assign a new parity drive and start the unRAID array by pressing "Start"   (during all this I've been saying "drives." You need one or more new "data" drives, and a new "parity" drive.  It could be as little as one data drive and a single parity drive, or, as many as 15 new data drives and a parity drive)

 

Because the data drives are already partitioned as unRAID expects it will not show them as "unformatted" when you start the unRAID OS and assign them to its array. It will not clear them, or format them.  They will just be added, with their data, to the array. The data will now be in unRAID.   Now that you have assigned a parity drive, the process of initially calculating parity will begin.  This will take a number of hours, but you can use the array while this is occurring...  Once done, your data will be protected under unRAID's software "raid"  (it uses RAID4, but without striping).

 

At that point, you still have your old software raid drives in the server, but un-assigned.  If you wish to re-use these in unRIAD, they can be assigned to the unRAID array.  As each is assigned, it will be treated as a new drive and cleared and formatted, so anything  on them will be erased.

 

Hope you did not get lost in that procedure 

 

Joe L.

Wow, thanks a lot for the writeup, that'll work! I guess I'll be ordering the Plus version pretty soon then

 

Thanks again!

Above procedure has been done successfully. My NAS is now running unRAID and all my data has been transferred.

 

Now onto restoring my vmware and lighttpd setup... 

 

Thanks again for you help.