RAID help?

RikuoAmero

Hey guys,
In a couple of weeks, I'm going to buy a 4 bay NAS device, I'm going to populate it with 4x 3TB Western Digital Red drives (unless I'm completely mistaken, Reds are supposed to be great for consumer level RAID).
The device I'm looking at says it supports RAID 0, 1, 5, 10.
http://www.dabs.ie/products/buffalo-linkstation-pro-quad-high-speed-4-bay-nas-enclosure-1-6ghz--diskless--1-x-gigabit-raid-0-1-5-10-8QP3.html

I want to have the usable space of 3 drives (so 3x3 = 9TB) with one drive as a backup/redundancy, but I'm not entirely sure which RAID level I should use.
https://en.wikipedia.org/wiki/RAID#Standard_levels
That page is a bit confusing. So...which RAID should I use?

Monotype

Sounds like you want RAID 5.
RAID 5 writes to all the disks except one and then writes parity (i.e., a checksum by adding the bits of the others or some equivalent) on the other one.
If one of the drives goes down, you can retrieve and rebuild the data.

However, if two drives go down, you've lost everything. Note that it's not a substitute for backup so unless this actually is backup itself, you wouldn't be extremely safe from situations which could cause the entire set to break (e.g., power surge frying your whole setup).

RAID 5 also takes a little extra processing power for writing. It can sometimes be a little slower, but CPUs have come a long way so I'd expect even a lower power CPU like this to be able to keep up. Reading should be faster than a single drive.


Yeah, the Reds are good. Frugal with power, quite fast (usually limited by the speed of the NAS though if the NAS is lower powered, so make sure you have a look at results of what speed the NAS itself offers aside from connection speeds) and has a reasonable warranty of 3 years.

RikuoAmero

Monotype wrote: »

Sounds like you want RAID 5.
RAID 5 writes to all the disks except one and then writes parity (i.e., a checksum by adding the bits of the others or some equivalent) on the other one.
If one of the drives goes down, you can retrieve and rebuild the data.

However, if two drives go down, you've lost everything. Note that it's not a substitute for backup so unless this actually is backup itself, you wouldn't be extremely safe from situations which could cause the entire set to break (e.g., power surge frying your whole setup).

RAID 5 also takes a little extra processing power for writing. It can sometimes be a little slower, but CPUs have come a long way so I'd expect even a lower power CPU like this to be able to keep up. Reading should be faster than a single drive.


Yeah, the Reds are good. Frugal with power, quite fast (usually limited by the speed of the NAS though if the NAS is lower powered, so make sure you have a look at results of what speed the NAS itself offers aside from connection speeds) and has a reasonable warranty of 3 years.

Thanks!