[mythtv-users] Software RAID5 no improvement to transferspeed...

Steve Adeff adeffs at gmail.com
Thu Jan 12 16:21:53 UTC 2006


On Thursday 12 January 2006 10:15, Johnathon Meichtry wrote:
> Using top check your load averages.  On my server where is it constantly
> recording 3-4 PAL DTT programs my load averages are:  load average: 0.24,
> 0.54, 0.71
>
> If yours show >1.0 then I would imagine you have a problem.  Software RAID
> in my opinion should take up no more than 3-5% if the server is busy.
>
> Also check "0.0% wa" as this is IO waits and would be greater than 30% or
> more if your SATA controller/disks is the bottleneck rather than the CPU.
>
> Johnathon
>
>
> ----- Original Message -----
> From: "Brian Wood" <beww at beww.org>
> To: "Discussion about mythtv" <mythtv-users at mythtv.org>
> Sent: Thursday, January 12, 2006 3:05 PM
> Subject: Re: [mythtv-users] Software RAID5 no improvement to
> transferspeed...
>
> On Jan 12, 2006, at 7:39 AM, Steve Adeff wrote:
> > well I got my software RAID5 up and running. 3 drives, no spares.
> > but I still get playback stuttering while recording 2 HD channels
> > and playing
> > 1 prerecorded HD show. The cpu usage hasn't gone higher than 96% so
> > I don't
> > think its a cpu usage problem.
> > I do have all three drives connected to the same onboard SATA150
> > controller
> > though I don't know if this could be a problem?
>
> It sure might be, whatever tool you are using to measure CPU load
> (top?) is averaging over some period of time, if the average is 96%
> then you are almost certainly hitting peaks of 100%+.

Just to let you guys know, it was an SQL issue, I sent a new email, but 
changed the subject announcing it... I had my other machine (over 100bT) 
running the SQL db, once I moved it back to the local machine it plays back 
fine.

thanks for the info though, some good info.

Johnathon: I don't even notice 3% use by the RAID, I've seen %wa as high as 
6%. I get load averges around 4 while watching HD and recording 2 shows.

Ramses: great command! I need to store that to my repertoire.

-- 
Steve


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