I'm running out of space on my array and I purchased a new drive to make my array larger.  I decided to go with one of the new WD Red disks as it seemed like a good fit for my always on unRaid media server and it wasn't too much more expensive.

 

My array consists of 2tb and 1tb drives and the new drive is also a 2tb drive so it would seem that I have a choice to make.  The red drive just passed 3x preclear with flying colors so now I have to choose whether to simply add it to the array (easiest option) or replace my current parity drive (a 1 year old Seagate 7200 RPM drive).

 

I have several questions:

1) Is there a reliability benefit to adding my new NAS rated Red drive as the parity drive?  It has the longest warrantee of all of my drives (at the moment) and it's rated for 24/7 use, but I'm unsure as to whether the parity drive is the one that will get the most use, especially since most of my NEW media will be downloaded to and read off of the new drive (since the other ones are almost full).

2) Is there a cost benefit to adding my new NAS rated Red drive as the parity drive since it has a lower 5xxx RPM rating?  Or does the parity only really spin up once a day when the mover takes everything over from my cache drive at like 4am. 

 

As I'm writing these questions I think I'm convincing myself to just add it to the array, but I'd be interested in feedback from the community.

I'd just add it to the array as another data drive.

You've already outlined the reasons very well ...

 

The parity drive is really only used during writes to the protected array ... and since you have a cache drive that only occurs once/day when the mover script is updating everything.

 

Whether replacing the parity drive with a lower rpm unit would make any difference in array write speeds depends on the areal density of your current parity drive, and the rotation speed and areal density of the other drives in your array => but the simple fact is that doesn't really matter, since all of your writes happen when you're not using the system anyway.

 

You'll likely use the new drive much more than the parity drive anyway, as I assume you'll be streaming all of the new media files that you write on the array, and most of them will be on that new drive.  And that drive's sustained data rate is far better than any Gb network can sustain, so there would be NO advantage to using a faster drive in its place (and, of that matter, it would outperform a 7200rpm drive anyway unless the7200rpm unit was also a 1TB/platter drive).

 

 

 

Thanks. Appreciate the quick response