[mythtv-users] Replace backend 3.5 system disk with 2 2.5 raid1?

[Eric Sharkey]

On Fri, Sep 26, 2014 at 10:08 AM, Mike Perkins
<mikep at randomtraveller.org.uk> wrote:
> On 26/09/14 14:09, Eric Sharkey wrote:
>>
>> On Fri, Sep 26, 2014 at 5:13 AM, Simon Hobson <linux at thehobsons.co.uk>
>> wrote:
>>
>>> It means that *every* write to the system filesystem has to contend with
>>> accesses to all the recording filesystems
>>
>>
>> The OS drive usage is dominated by reads.
>>
> Er, no. Every time that a recording is written to one of the storage
> directories a write is also issued to the database to update the seek table
> for that recording.

Which is pretty small compared to the size of the recording itself.

Dominated by reads doesn't mean exclusively reads.

> That is why it is recommended that the mysql database is not placed on the
> same spindle as any storage directory, because you're automatically doubling
> the head movements - at least.

The database should be on an SSD and the recordings should not.  With
current pricing, it's hard to justify any other configuration unless
it's a really small budget one disk set up.

Eric