BTRFS 3 copies vs parity

[PicoCreator]

Hey all,

 

I am planning to replace my existing off the shelf NAS (2x3TB Raid 1). With a new custom build (RPC-4224 with 6 drives salvaged from various computers). And is waiting for my thumb-drive of unraid, and the hardware parts to arrive.

 

While I am familiar with linux and LVM due to their heavy usage at work. I am currently exploring the usage of BTRFS for my new NAS replacement. And plans to fiddle around with it, once the parts arrive.

 

My questions are broken to the following 3 parts.

 

[*]Does the unraid btrfs UI allow me to setup with n-copies > 2 ?

[*]Can I rebalance btrfs n-copies from 2 to higher when I add in a new drives in future ?

[*]Since every file already includes a CRC checksum. If I setup with n-copies of 3 and larger. Is there a use for a parity drive ?

• Since CRC already detects bitrot
  
• And when n-copies >= 3, i can do a recovery of any one failure / rot, from the remainder.
  

 

[BRiT]

1. No.

2. No.

3. No.

 

There is no support in the UI for that. Its all manual reconfiguration and manually figuring out the commands and order to invoke them.

 

[gundamguy]

1. No.

2. No.

3. No.

 

There is no support in the UI for that. Its all manual reconfiguration and manually figuring out the commands and order to invoke them.

 

I'm not sure that's quite right, it doesn't let you do anything but raid 1 but I thought expansion and balance was handled by the unraid gui for Raid level 1.

[PicoCreator]

@gundamguy

 

How bout without the GUI? I would be fine with the command line. Specifically 3, because i am contemplating between n-copies >= 3 vs parity as well.

[gundamguy]

Yes you should be able to do that in command line... BTRFS pools only work for the cache slots so I'm not sure it's using unraid is worth it at that point.