Need to expand my NAS. What's faster?

[Ezekiel]

I have a RAID 5 that I'm expanding from three 12 TB drives to four 12 TB drives. As I wait for the new hard drive, I am copying all the data to some external drives, in case something goes wrong. I remember that when I set up the array, it took about twenty hours. So, which is faster?

Expanding the RAID through the normal process.

Wiping the RAID, starting it over from scratch with four drives instead of three and moving all the data back.

 

[Gordon_4]

I have a RAID 5 that I'm expanding from three 12 TB drives to four 12 TB drives. As I wait for the new hard drive, I am copying all the data to some external drives, in case something goes wrong. I remember that when I set up the array, it took about twenty hours. So, which is faster?

Expanding the RAID through the normal process.

Wiping the RAID, starting it over from scratch with four drives instead of three and moving all the data back.

I would think that simply adding a new volume to the array would be faster than a full rebuild.

 

[Ezekiel]

I would think that simply adding a new volume to the array would be faster than a full rebuild.

The reason it might take very long is because it has to redistribute all the bits of data and parity over the four drives. Somebody told months back when I asked about expanding the array that it might take longer than starting over and copying everything but not to quote him on that.

Turns out, though, that between my external drives and what's available on my internal drives, I don't even have enough storage to back up everything on the NAS. I hope the hard drive and RAID controller get here soon. I can rip all my movies and TV shows again again, but having to delete the backups to almost all my digital only files to make room for these time-consuming rips (in case something goes wrong with the expansion) stresses me out.

 

[Ezekiel]

I started at 2:45 PM on Thursday and finished at 7:14 PM on Sunday. Three days and four and a half hours to redistribute 21 TB of data. Yeah, starting over and copying everything would have been much faster, if I had the storage.