[mythtv-users] Reassemble RAID with mdadm

[John Drescher]

> On a modern CPU, there is a theoretical slowdown calculating parity, but
> my quad core runs about 5% of one core when I'm thrashing the drives hard.
> Frankly, any modern system has CPU to burn, and I don't believe parity
> calcs are a real-life impact on performance.
>

Agreed. Even on 5 year old systems the cput hits 7% max unless the you
are rebuilding or reshaping then it can hit 25% on 1 core..

> RAID5 is the most space/cost efficient.  You get n-1 space, so with a 5
> drive array, you get 4 disks worth of space.
>
Agreed again

>
> I had a lot of problems with RAID5 and consumer grade disks.  My disks are
> generally failing about 1 every 3-6 months, in a 6 disk array.  Which makes
> sense if you figure the life of a drive is 2-3 years.  My theory here is
> that consumer grade drives are made to a budget.  They give a 3 year
> warranty, but they're assuming you don't run it 24x7.

There is something very strange here. I have 100+ such disks in raid
and  I see 1 to 3 total failures per year running 24/7/365. And these
are systems that I guarantee are used more than your Mythtv box.

John