Hello,

Just looking for some advice and feedback. Have been running the wonderful DiskSpeed plugin from jbartlett777 and noticed that my Parity 1 disk doesn't have a smooth speed curve and is a little slower than the other parity drive and one of the data drives meaning it's a slight bottleneck to the array write speed.

It's not critical, but given that I have two parity drives and Disk 4 will at some point fail and be swapped with a larger faster drive, I'm thinking to swap Parity 1 and Disk 3 now.

Would love if someone more experienced than me with such things could sanity check this thought and confirm if they would do the same in this situation?

If it is reasonable to do this, would an efficient (and safe) method be the following:

1. Drop Parity 1 as a Parity drive and then add it back as a Data drive (would Parity 2 become Parity 1 automatically or could this be explicitly configured in some way that means there's always parity coverage?)

2. Allow parity to fully rebuild

3. Use Unbalanced to move (or copy?) all data on Disk 3 to the new data drive

4. Remove Disk 3 as a data drive and re-add it as a Parity drive (either Parity 1 or Parity 2 depending on step 1)

5. Allow parity to fully rebuild

I'm not super experienced with this stuff, so any warning or insights appreciated.

10 hours ago, havet24069 said:

would Parity 2 become Parity 1 automatically or could this be explicitly configured in some way that means there's always parity coverage?)

It would remain as parity2, but still protect the array.

10 hours ago, havet24069 said:

Allow parity to fully rebuild

Parity doesn't build when you add a new disk, the disk is cleared.

10 hours ago, havet24069 said:

Remove Disk 3 as a data drive and re-add it as a Parity drive (either Parity 1 or Parity 2 depending on step 1)

To remove disk3, you would need to do a new config, then re-sync both parity drives, i.e., the array would be unprotected during that part, just to be clear.

Hi Jorge, thanks for taking a look at this.

1 hour ago, JorgeB said:

To remove disk3, you would need to do a new config, then re-sync both parity drives, i.e., the array would be unprotected during that part, just to be clear.

Ah thanks, that's the kind of thing I was concerned about. It's not the end of the world but given it takes over two days to rebuild parity with this array I'm keen to avoid it if possible.

There is just enough space to temporarily place the content from Disk 3 on the other disks in the array if I split it up. Does this open the possibility to do it without any period of being unprotected?

If in the end you want to remove that disk, it would still require a re-sync.

The only way to shrink the array and keep parity is using this:

https://forums.lime-technology.com/topic/61614-shrink-array-question/?tab=comments#comment-606335

23 hours ago, JorgeB said:

If in the end you want to remove that disk, it would still require a re-sync.

The only way to shrink the array and keep parity is using this:

https://forums.lime-technology.com/topic/61614-shrink-array-question/?tab=comments#comment-606335

Ah, interesting - I hadn't really thought about it as a shrink operation but yes I guess that's technically one of the steps. Need to look into that a bit more and see if I want to go ahead - possibly a bit of pain now to sort it out may well be better than trying to do it later.

Thank you for taking the time to answer on this.