Speed of the Parity drive, important ?

[Pducharme]

Hi,

 

I currently have a 4TB 3.5in 5900RPM parity drive and it goes well.  But, I have a single drive.  I want to benefit from the new Dual Parity drive feature.

 

I came across a killer deal on a Seagate 4TB 2.5in, 5400Rpm.  It's an external, but I know it's a SATA3 inside. (ref: http://www.servethehome.com/seagate-4tb-2-5-drives-fall-105/).  I can have one for 63$ Tax-in, delivered, so at that price, I ordered one.

 

My question is, what would you Unraid community recommands between those option :

 

- Buy 2 of that Seagate 4TB 2.5in 5400rpm and use them as dual parity drive, then repurpose the current 3.5in 5900rpm 4TB parity drive to the array.

 

or

 

- Buy 1 of that  Seagate 4TB 2.5in 5400rpm  and add it as a 2nd Parity to my current 4TB 5900rpm 3.5in drive (my current parity).

 

or

 

- Stay way of that !!

 

 

My goal is to not slow down my file copying tasks and disk I/O when accessing data un my Array.  I have a SSD cache drive (Samsung EVO 840 512GB) and couple of share with "no Cache", but most of them are using the cache.  If using such disks as my Parity dual just mean that my monthly Parity check will take couple hours more, then I don't care !?

 

What would you guy do ?

 

 

 

[xanyx]

Where did you find that drive for $63?? It sounds like a killer deal if it ends up being suitable for an unRAID array...

[Pducharme]

some dude at my work know a guy that know a guy

[tdallen]

Do you have another 4TB 3.5in 5900RPM in the array?  I like to do things the hard way  so if I had another 5900 RPM disk in the array I'd buy the 5400rpm drive for the array and rearrange things.

 

I'd have a minor reservation about buying two of the same disk for parity at the same time- the possibility that disks from the same "batch" might have similar failure characteristics and fail around the same time.

[JonathanM]

I'd have a minor reservation about buying two of the same disk for parity at the same time- the possibility that disks from the same "batch" might have similar failure characteristics and fail around the same time.

I'd much rather have a parity drive fail than a data drive. No actual data loss. Second drive failure = data loss (assumes single parity), if both failures were data, you lost both, even with intact parity.