[mythtv-users] Opinions on Solid State Drives for Myth ???

Brian Wood beww at beww.org
Tue Jul 27 18:08:36 UTC 2010

On Tuesday, July 27, 2010 11:49:59 am Travis Tabbal wrote:

> For the OP, I don't see any reason to fuss with SSDs for Myth. They are
> faster for seek times, but if you're not trying to share spindles you don't
> need to worry about seeks so much. I can't think of anything that a Myth
> BE/FE does that would really make a big difference with. Faster DB
> transactions certainly, but enough to make a difference that you would even
> notice? I don't know. Worth a try I guess if you want to, you could always
> move the SSD to another box later if you don't see a worthwhile difference
> in Myth.

Thanks, that's essentially what I figured, but of course I might be missing something obvious (again).

I wondered if there might be cases where an SSD would actually be *worse* than a spinning drive.

Looking into that, I ran into this interesting quote from Linus Torvalds:

"And the sad part is that other SSD's generally absolutely suck when it comes to especially random write performance. And 
small random writes is what you get when you update various filesystem meta-data on any normal filesystem, so it really does 
matter. For example, a vendor who shall remain nameless has an SSD disk out there that they were also hawking at the 
Kernel Summit, and while they get fine throughput (something like 50+MB/s on big contiguous writes), they benchmark a 
pitiful 10 (yes, that's ten, as in "how many fingers do you have) small random writes per second. That is slower than a 
rotational disk.

In contrast, the Intel SSD does about 8,500 4kB random writes per second. Yeah, that's over eight thousand IOps on random 
write accesses with a relevant block size, rather than some silly and unrealistic contiguous write test. That's what I 
call solid-state media.

The whole thing just rocks. Everything performs well. You can put that disk in a machine, and suddenly you almost don't 
even need to care whether things were in your page cache or not. Firefox starts up pretty much as snappily in the cold-
cache case as it does hot-cache. You can do package installation and big untars, and you don't even notice it, because 
your desktop doesn't get laggy or anything.

So here's the deal: right now, don't buy any other SSD than the Intel ones, because as far as I can tell, all the other 
ones are pretty much inferior to the much cheaper traditional disks, unless you never do any writes at all (and turn off 
'atime', for that matter)."

I've never known Linus to push hardware, at least not since the 90s when he recommended the Alpha CPU, and we all know how 
that turned out in the end.

More information about the mythtv-users mailing list