[mythtv-users] SSDs and Myth frontends ?

[Brian Wood]

On Friday, September 17, 2010 07:26:19 am Dave Richardson wrote:

> 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'm using a clone of a stock Kubuntu 10.04 system, EXT4 and the CFQ scheduler. Moving to the Deadline scheduler didn't 
seem to help much, if at all.

There are filesystems that are optimized for SSDs, but I'm not sure I want to try one with Myth at this point.

I have also found Firefox to be the only application to show any negative aspects. The fact that Chrome runs normally 
indicates the problem is not inherent with web browsing, but to the way FF does it.

BTW - cloning a drive to a smaller one is not as simple as moving to a larger drive. I suspect that as more people move to 
SSDs, which will tend to be smaller than the source drives, this problem will become more obvious. The simple DD approach 
causes problems with the partition table sizes, not a problem when moving to a larger drive, just resize them after the DD 
copy, but that won't work in the move to a smaller drive. It can be done, but is more complicated.

> 
> 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.

Anything involving reading from a DB should be fast, SSDs excel at reading, not so much at writing. This explains Eric's 
observation about MYSQL reading operations, which have always been slow on my HDD-based system.

Moving to a RAID0 array on my main BE did speed up MYSQL operations, which also makes sense, but that's only a 2X increase 
in read speed, while the SSD should be more like 3 or possibly 4 times faster at DB reads.

> 
> 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!

Yeah, sometimes I forget that Myth is for watching content, not tinkering around, though both are fun.

But it sounds from everyone's comments that either a Myth FE or BE should run OK, and some operations might actually be 
faster.

Much thanks for everyone's input.