[mythtvnz] New list member - Hardware recommendations

[criggie]

On 13/01/12 11:42, Wade Maxfield wrote:
> On 12/01/2012, at 8:12 PM, criggie wrote:
>
>> Why?  The mysql output is a single record to the recordings table, a
>> single record in the recorded table, and maybe a few state updates that
>> the tuner is in use.
>
> Plus the 7200 entries in the recordedseek table per hour of each recording.  Multiply that by the number of simultaneous recordings you can do, plus the number of user jobs, plus number of playback streams and it can get to be a meaningful number.  Add in the scheduler as well.  That seems to be the biggest bottleneck in bigger systems.  People have had spluttering recordings when the scheduler kicks in, mainly on systems with large numbers of schedule rules, high number of channels, and high number of tuner inputs and where they share the same drive for recordings and mysql.
>
> Personally I have 2 recordings drive (2 x 1TB) and a separate OS drive.  With 2 DVB-S cards set to 3 virtual tuners each, plus the PVR150 for Sky that's 7 simultaneous recordings (which does happen quite regularly with post-roll overlap settings), 3 commflag jobs, plus up to 4 playback streams (only 4 people in the house at the moment) and at peak times there can be quite a high level of disk activity, not just in MB/s but in I/Os.
>
> I'm not saying everyone *HAS* to have a separate drive, but it can be useful as your system grows.

Yeah okay you're right and I was wrong.

My sql database is 335 MB, so it might be feasible to make a raid1 with 
a partition and a ramdisk.  In theory the writes complete when one disk 
is written, so that would be the ramdrive.  And the data on the hard 
drive would provide the permanent storage over a restart.

Opinion?


-- 
Criggie

http://criggie.org.nz/