[mythtv-users] Software RAID5 faster than RAID10?

[Raymond Wagner]

Ben Curtis wrote:
> <snip>
>   

You do know how striping works... right?  With raid10, you are striping 
two mirrors, so you have the combined sequential speed of two drives.  
With raid5, you are striping three disks, with a fourth for parity (not 
quite how it works), so you have the combined sequential speed of three 
drives.  Higher sequential speed on raid5 seems obvious.

Now the problem is that any read and any write on raid5 must access all 
the disks, so you end up with roughly the same IOop rate as with a 
single drive.  With raid10, you now have two independent sets of data.  
You must write to all disks at once, but you can read from either disk 
in the mirror, doubling concurrent IOops.

Of course this is all moot for storing recordings.  One independent disk 
for each tuner that could be recording simultaneously is the ideal setup.