[mythtv-users] Wake up disks on events

James Crow james at ultratans.com
Thu Sep 11 17:25:43 UTC 2008

On Thu, 2008-09-11 at 08:35 -0700, Brad DerManouelian wrote:
> On Sep 11, 2008, at 8:22 AM, John Drescher wrote:
> >>> You could also install a flash card reader and put the database  
> >>> files
> >>> on a flash drive. Granted, it might tend to slow things down, given
> >>> how slow these things are at writes, but it would definitely consume
> >>> less power.
> >>
> >> That's a terrible idea. Flash drives can't keep up with the read/ 
> >> write
> >> demands of a database application in terms of speed or longevity.
> >> Don't do that.
> >>
> > I think it would be perfectly fine if you get an 8GB or 16GB flash
> > drive for the os that has wear leveling ( how many flash drives do not
> > have that) and tune your kernel so it writes less frequently. In this
> > case the flash drive will last longer than the average hard drive.
> Yeah. I take that back. Please install a flash drive for your database  
> and let me know how that works out for you.
Some flash devices do not die immediately. I used a 1G CompactFlash
device as my boot OS for my car computer for about 2 years. (I
originally got it for a steal at $160) The system ran fine from it
albeit much slower boot time than with traditional rotating HD. With
that said, how much does an 8GB flash drive cost? $20 maybe half that on
sale. I would worry about data speeds more than the flash wearing out.
>From the reviews I have read I happen to own one of the fastest flash
based USB drives and it tops out under 20MB/sec write speed. My internal
SATA devices can easily approach 40MB/sec and they are basic 8MB cache
7200 RPM.

I would not worry about wearing out a flash drive, but I would worry
about the speed hit the entire system would take from the slower flash
speed. On this list it is often stated that moving the OS and MySql to a
different spindle than recordings will improve speed. I saw my own
system become more responsive, especially while looking at the guide, by
adding a dedicated recording drive.

So I agree with Brad, try out a flash drive for your DB files and let us
know what that does to overall responsiveness of the system. :)

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