Mark Knecht, mused, then expounded:

> Hi all,
>    I'm wondering what folks who understand Linux configuration better
> than I do about a problem like this. I run media all day while working
> on my Gentoo/KDE box. The machine is generally over powered for 99% of
> the work I do. It works _very_ hard when I kick off big numeric runs
> (i.e. 100% usage for 2-30 minutes) but most of the time CPU usage is
> running at <1-2% while I'm doing things like editing code and watching
> a movie at the same time/
>
>    What I do notice however is that whether I'm watching NetFlix in a
> VM or a movie on disk using VLC, when I insert a DVD I almost always
> get a glitch of 1-2 seconds while the system figures out what to do
> with the DVD. I see some CPU usage, but it's not like 12 processors go
> to 100%.
>

As no one has stepped in here...Pretty much everything I;m suggesting,
you are going to hate.

   - Turn off that system sucking automount daemon.

Hopefully, that fixes the issue for you.  The rest are more drastic.

Here are the important things for a VM host, in order of decreasing
importance -

   1) Storage - needs twice as much, must be fast.  7200 RPM SATA drives
   are acceptable for read only NFS stores.

   2) Memory - all DIMM slots filled, 8GB 1600 PC3-DDR DIMMS minimum.
   Faster, lower latency, DIMMs preferred, but motherboard/bios may
   down clock them.

   3) Network - Wide bandwidth (Probably not an issue for you).  10GigE
   minimum.  Or bond at least 4 GigE ports to act as a single pipe.

   4) CPU - Lower core count, 8-cores/socket max.  More eats up I/O
   Bandwidth, adds latency, generates wait states.  Better to
   oversubscribe the cpu than anything else.

On an even more micro level -

   Storage - Make sure you have seperate drives for the OS - mostly read
   only), /var - mostly write, and /home - mostly read, light write.
   Typical setup would be a single SSD for the OS, RAID 1 for /var and
   whatever RAID you like for /home using 10K RPM SAS drives preferred.

   Use the proper file system - large sequential files: media, VM
   images, etc. need XFS.  Small r/w files need - EXT3.

   Use a proper hardware RAID card - not a software raid.  Proper
   hardware raid cards will require a x8 PCIe slot and cost a few
   hundred dollars.

   Reduce the cpu core count to 4 and offload your numeric compute
   requirements to a stack of RasberryPI compute engines, using your
   main system as a head node for the cluster.

Bob
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