Following a glowing recommendation we are looking at using a de-commissioned DELL server with Unraid as a NAS alternative to a Synology upgrade.  

 

The Dell box has 192gb of memory and 18tb of storage.  We have used the DELL hardware BIOS to build the raid set up as a single Raid 5 configuration.  

 

I am confused on how I should apply this in the UNRAID configuration.  

 

I effectively do not have parity drives but technically should not need them as if a drive fails the DELL BIOS / RAID will handle this.  

 

Should I unraid the drives on Dell box or should I just allocate them as a single drive in Unraid ?  

 

Edited February 6, 20215 yr by Gigglepot
clarification of heading

5 minutes ago, Gigglepot said:

We have used the DELL hardware BIOS to build the raid set up as a single Raid 5 configuration.

unRAID is not RAID (therefore, the "un") and does not work with RAID configurations in the array.  It wants to see all of the drives as individual drives and not as a RAID array.

 

unRAID offers disk failure protection much like a RAID does, but with some distinct advantages:

• Each disk in unRAID has its own file system and can be read individually outside the array if need be
• Losing more drives than you have parity drives (either 1 or 2) results only in the loss of data on those "extra" drives.  You do not lose EVERYTHING as you do with a RAID array
• 1 Parity drive can protect a lot of data drives against hardware failure.  You can have 2 parity drives if you wish to protect against the simultaneous failure of two drives instead of just one.  There is no hard and fast rule, but many opt for dual parity with 8 or more data drives.  Some (because they have good data backup) will protect a dozen or more data drives with single parity.  You should always have a good data backup plan as parity only protects against hardware failure and not data loss
• No striping of data across disks means that a particular file will live on only one disk
• You can add disks of varying sizes, makes and models to increase storage space as needed.  RAID requires same size and usually same make/model.

There are a couple of disadvantages as well, but obviously, we accept those for the advantages unRAID offers:

• Read speed is limited to the speed of a single disk (see no striping above)
• Write speed to the array is slower than with RAID.  There are ways to speed that up via caching first to SSD and turbo write

The bottom line is that, if you want to use unRAID, you should break the RAID on the Dell, add the disks individually to the unRAID array and designate at least one disk as parity and the rest as data/array drives.

Thanks for the clarification Hoopster.  I will remove the Raid 5 configuration and use the separate disks as you recommended.  👍