[mythtv-users] Switching backend IDE drives to libata with 2.6.28 kernel

[Tom Dexter]

On Mon, Jun 1, 2009 at 2:05 PM, Tom Dexter <digitalaudiorock at gmail.com> wrote:
> <delete>
> The one that has be a little concerned is the multiple sector I/O
> hdparm setting (-m) which isn't supported either.  From what I've seen
> so far, libata seems to default this to 8 when the drives max is 16.
> Except for WD drives, I don't see anything in the hdparm man page that
> would lead me to believe that 8 would be better than 16.  As a matter
> of fact, I never even used the -m option in hdparm, as the old driver
> defaulted to 16.
>
> My backend has two 500GB Seagate IDE drives.  I haven't had a good
> opportunity to get rid of my lvm partition in favor of storage groups.
>  The lvm spans the drive that also has the / partition and the MySQL
> databases.  I know that's not an ideal setup, but adding a drive would
> be nightmarish, and in any case, it currently works fine the way it
> is.  I can record three HD shows at once while watching another
> previously recorded program with no problems at all.
>
> I really don't think I can afford to loose even a hint of disk
> performance on that setup, which is why I started looking so carefully
> at this one.  Any advise would be appreciated.
>
> Tom
>

I decided to just make the plunge and try the switch, since it's
certainly not irreversible.  My drives are at all the default settings
chosen by libata, including the multiple sector I/O of 8 that
concerned me.

Wow...obviously my concerns for unfounded.  I'm pretty much torture
testing is as I write this.  It's unquestionably more reliable that it
was with 2.6.27 and the old IDE drivers.  Right now I have three shows
recording (1 at 720p and 2 at 1080i), while the frontend is playing
yet another 1080i recording.  After that worked without any issues I
added two commflagging jobs on the backend and it's humming right
along flawlessly.  I know this would have given me IOBOUND errors
before.

Very very cool.

Tom