Migrating from FreeNAS to UnRAID Question

[manifest3r]

So I have a zpool of 4 disks containing the following:

2x 1TB WD Red

1x 1.5TB WD Green

1x 2TB WD Green

 

My UnRAID currently contains:

1x 120GB SSD Cache

1x 500GB Data

 

UnRAID hardware:

Intel Xeon X5670

22GB DDR3 RAM

AMD 7950 Boost

 

I have a 3TB drive I plan to use for UnRAID, currently not installed.

 

I plan on installing the 3TB drive, preclear, and make it part of the array, then migrate all my data over. After the migration, my biggest risk would be all the data being consolidated on a single drive.

 

I would then move my drives over to the UnRAID box, preclear, and make it part of the data array, and make the 3TB drive a parity drive - is this possible?

 

After Migration - Unraid:

Cache

1x 120GB SSD

 

Data

2x 1TB WD Red

1x 1.5TB WD Green

1x 2TB WD Green

 

Parity

1x 3TB Seagate

Edited April 25, 2017 by manifest3r

[JonathanM]

1 hour ago, manifest3r said:

I would then move my drives over to the UnRAID box, preclear, and make it part of the data array, and make the 3TB drive a parity drive - is this possible?

Possible, but rather risky. It would be a much better idea to source enough drive space to leave the original drives intact as a backup.

[manifest3r]

None of the data is absolutely critical, that's all backed up to Amazon Drive or Dropbox or Google Drive.

 

I don't mind the window of failure I might have - it would just be an inconvenience if something were to happen to the drive.

[JonathanM]

You would need to copy the data twice. Once from your operating FreeNAS box to your operating unraid box with the 3TB as a data drive, then again from the 3TB to the other unraid data drives after you scavenge them from the FreeNAS box. There is no need to clear or preclear the drives to use them in unraid, as you will not have a valid parity drive at any point of the copy process. Clearing is only necessary to maintain parity protection when adding new drives to additional data slots in a parity protected array.

 

Healthy drives are a necessity in a parity protected array though, as all bits from start to finish of all drives must be read perfectly, regardless of whether they actually contain any sensible data. Do not add any drives to unraid that you do not know to be in perfect health. If that is what you were referring to when mentioning preclear, go right ahead, preclear is a very good way of testing a drive.

[Frank1940]

Personally, I would buy a second 3TB drive and start out with a parity protected array.  Those drives are right in the $100 range presently.  Then copy the data from the FreeNAS box DIRECTLY to the array.  (That 120Gb cache is too small to be of much use.)  If you use The reconstruct write (aka, Turbo write), it will be almost as fast as copying to a cache drive. 

 

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