[mythtv-users] My First MythTV Box

Don Jerman djerman at pobox.com
Tue Jan 1 00:02:03 UTC 2008

On 12/31/07, Mike Perkins <mikep at randomtraveller.org.uk> wrote:
> match at ece.utah.edu wrote:
> > On 30 Dec 2007 at 19:54, lists at benzo8.org wrote:
> >
> >>> On Dec 30, 2007 1:01 AM, John Sullivan <lists at benzo8.org> wrote:
> >>>> RAM             2 x DIMM 1 Gb DDR2 800 MHZ KINGSTON HYPER-X
> >>>> HD 1            HDD 80 Gb 7200 RPM SATA II
> >>>> HD 2            HDD 250 Gb 7200 RPM SATA II
> >>> I dont know much about DVB but if  I was you i would save some money on
> >>> RAM.  1 Gig is plenty.  I would go with 2 512mb sticks to get dual
> >>> channel.
> >>> With the extra money I would get some more storage!  Are you buying a
> >>> 80Gig
> >>> HDD?  Or is that a left over that you have?  500GB are only $100 USD  I
> >>> would get atleast one.
> >> Thanks for the advice - I'll shift some funds from memory to HDD - upgrade
> >> the 250GB to a 500GB... I'll be buying all the drives new, but I was
> >> thinking that the 80GB is just a systems/DB disc and so doesn't need large
> >> amounts of space - am I mistaken?
> >
> > You're not necessarily mistaken, but an 80GB drive just makes no sense at
> > all. Look at it this way:
> >
> > 1. You only have a few physical spaces in the box to mount HDD's, so if
> > you're going to have 2, then have 2 large ones. You'll never regret having the
> > additional storage space.
> >
> > 2. That 80GB drive will make about the same amount of noise and consume
> > about the same amount of power and hence generate about the same
> > amount of heat as the 500GB.
> >
> > 3. At this time I don't see much value in having the system/DB on a separate
> > disk, do you?
> >
> Wrong!
> It is an *extremely* sensible idea to separate your system files and your Mythtv
> files onto separate disks. *Especially* to put the Mysql database on a separate
> disk to the video storage. When recording there are many I/Os to the video disk
> at the same time as many I/Os to the Mysql database. You really don't want to be
> thrashing your heads from one file to another at the rate video comes in.
> For the system disk you don't even need 80Gb, but if that's what you got, go
> with it.
> Mike Perkins

I tend to value the bays more.  I would agree if they were IDE drives,
but this board supports SATA-II, and you should use it.  3Gbps = about
22GB/hr, HD streams are about 7GB/hr so you can play 1 and record 2
and have change left over for mysql and mythweb - on a single SATA
channel.  Of course if you plan to work it harder than that, you
probably need more drives and channels anyhow.

By the way, the business about mysql beating up a drive is probably
bogus - Google studied hard disk failure (they have a rather large
farm, and a good motivation to study this) and the bottom line is that
utilization and temperature have weak correlation to lifespan after 6
months: http://research.google.com/archive/disk_failures.pdf

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