[mythtv-users] SSDs and Myth frontends ?

Dave Richardson mythtv at derdev.com
Fri Sep 17 13:26:19 UTC 2010


On Fri, 17 Sep 2010 07:10:39 -0600, Brian Wood <beww at beww.org> wrote:
> On Friday, September 17, 2010 06:58:14 am Dave Richardson wrote:
>> On Thu, 16 Sep 2010 18:22:15 -0600, Brian Wood <beww at beww.org> wrote:
>> > Someone just gave me a 64GB SSD (probably buttering me up for some
>> > other
>> > favor in the future, like building him a Myth
>> > system).
>> > 
>> > I was thinking about replacing the 2.5" HDD that came with my Revo
with
>> 
>> it.
>> 
>> > I don't really see any advantage, other than power consumption, heat
>> > and
>> > reliability.
>> > 
>> > But I have read a few things about the net about SSDs causing long
>> 
>> pauses,
>> 
>> > but of course these were Windows users, and I
>> > know Windows is not optimized for SSDs, and there are some parameters
>> 
>> you
>> 
>> > can tweak in Linux to handle them better (like
>> > which scheduler, mounting with noatime, not swapping to it etc.).
>> > 
>> > Anybody see any reasons to not go with an SSD for a frontend? As I
>> > said,
>> > I'm not looking for any great improvement over a
>> > conventional SSD, but my other option is to netboot the frontend,
which
>> > would be even quieter, draw even less power and
>> > make even less heat than an SSD.
>> > 
>> > Hmmm, seems like I am talking myself into netbooting :-)
>> > 
>> > Although 64Gb is large enough to hold an OS and a Myth B/E, I don't
see
>> > any reason to try the SSD in my BE, it's already
>> > spinning many drives anyway, and is located in the garage so noise is
>> 
>> not
>> 
>> > a factor.
>> > 
>> > If it matters, it's a (relatively) cheap Kingston unit, I've seen
them
>> > around for $120. I know Linus says to not buy
>> > anything but an Intel SSD, but he probably has more money than I do,
>> > and
>> > may get hardware for free.
>> 
>> I've built a couple dedicated FEs using 32GB SSDs.  I've noticed some
>> lagginess when using Firefox, but apt updates seem to work very
quickly.
>> Not sure if there's correlation in the disk IO between those or not.  I
>> have been very pleased with Myth FE performance using SSD.
> 
> 
> 
> Funny you mention that, I'm testing the unit with a clone of my desktop
> system (Kubuntu, not Myth). Firefox seems to be 
> the main problem, stalling for long periods, and getting many "a script
> has stalled" messages, but hitting "stop the 
> script" doesn't seem to help, I still have to wait.
> 
> OTOH, OpenOffice opens MUCH faster than with a conventional HDD, but
that
> makes sense.
> 
> I have done everything  have found suggested, including moving to the
> deadline scheduler, having Firefox cache to RAM and 
> a couple of other tweaks. FF still stalls a lot. Interestingly Chrome
> seems to run fine.
> 
> Most of the "optimizations" I have found, other than changing the
> scheduler, seem to be mainly to minimize disk writes and 
> thus preserve the life of the SSD, such as mounting with "noatime".
> 
> This is why I am leery of using an SSD for Myth, I don't need something
> that often stalls the system for long periods.
> 
> 

Yeah, well, as I say, Firefox seems to be the only app from Mythbuntu
install that lurches - which might be attributed to how Mozilla elected to
reference the file system libs, or the nature of browsing (lots of little
files), or who knows.  I'm fairly sure my SDD was formatted as EXT3 or
EXT4, I didn't change the Mythbuntu 10.04 default OS format.

I can, again, vouch that Myth and playback of recordings & videos are very
speedy (meets expectations).  System boots are very fast, and I didn't have
to do a thing to declare any boot parameters or otherwise manage the
install/config of Mythbuntu to get the SSD to operate - it just worked. 
Managing/downloading packages via 'apt' moves along quite nicely as well.

I did at one point spend some time creating a 1GB RAM drive on one FE (I
had installed 4GB, way more than Myth needs) to see if that would work for
/tmp, /var/log and some other stuff that I assumed gets written to disk
during normal Myth operation on an FE.  It all worked, but I didn't bother
continuing to deploy that RAM drive onto subsequent FE builds.  I reasoned
that a) I'd gotten proficient enough with installing from scratch and b)
that SSD media would continue to decline in price such that if I "wore out"
an FE SSD from writes, I'd just replace it and rebuild in an hour. 
Basically I got it working, decided to be lazy and enjoy the system.  Maybe
I didn't do enough hobbyist tinkering, but I blew most of that energy on
the dedicated BE so it was time to actually watch some programming.

Good luck!







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