[mythtv-users] Planning Tuners and Disk I/O for a MythTVBackend System

Ben Kamen bkamen at benjammin.net
Mon Feb 8 16:27:14 UTC 2010

On 2/8/2010 1:37 AM, Raymond Wagner wrote:
> On 2/7/2010 22:37, MythTV wrote:
>> Recording speed with 12 tuners requires 12 concurrent streams to be
>> written to the disk. The
>> bottleneck becomes the seek times and rotational latency.
> On 2/7/2010 23:00, Ben Kamen wrote:
>> Could always start striping drives in a raid 0 kinda deal. :D
> No. Striping causes the same exact problem. You still have all the disks
> seeking in unison, you just end up with significantly higher throughput.
> If you've got proper hardware RAID with write-back cache, it may be able
> to re-order the writes to be more sequential. The whole purpose of
> Storage Groups added in 0.21 was to allow you to add multiple
> independent drives to MythTV, and allow it to properly load balance
> between them.

I wasn't saying in Software (although I didn't exactly except it) - it would most definitely be in hardware.
And that hardware would have to have a delayed-write caching mechanism.
I wonder how many modern MB with RAID capable SATA controllers support such a thing.

I'm using the Myth storage group option having added (2) 250GB drives making sure they were on different IDE busses.
It's fabulous.


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