[mythtv-users] Diskless

Rich West Rich.West at wesmo.com
Wed Jan 31 00:19:48 UTC 2007


Andrew Wilson wrote:
> I run a diskless frontend on an epia m10k with 512MB RAM. It works
> just fine. Root filesystem is on the network. The server is a low
> power Maxtor Shared Storage - similar in concept to Linksys NSLU2. It
> boots the frontend using the excellent dnsmasq server for dhcp and
> hpa-tftpd for tftpboot - took a while to get this going, but now it is
> flawless. The frontend power button is ACPI'd to suspend to RAM, so it
> 'boots' in about 5s unless I need to power off. Frontend draws about
> 3W when suspended - which is about the same as when it is OFF but
> still connected to the PSU... Shocking!
>
> The backend is a cheap (20!) compaq small form factor office pc which
> lives in a cupboard. It has 256MB RAM a pair of (cheap) DVB-T cards,
> and a small disk for OS and swap, though I've not needed the swap and
> I could probably boot this over network as well. Recordings are stored
> on a NFS mount on the MSS.
>
> The Maxtor box runs cool, draws about 7W and is on 24/7. It also has
> the task of waking the backend when a recording is imminent. The
> backend draws about 25W when on, and the frontend draws about 30W. I
> also have a belkin wireless adsl router which draws about 17W. In
> theory the MSS could do this job as well, but to be honest I've not
> tried, and I don't really have time.
>
> Everything works OK. The network is wired 100 base tx, not even close
> to being saturated. When HD-DVB comes along I'll probably need to
> upgrade the frontend, but hey I'll need to upgrade my TV first! The
> network should still be OK, and the backend should be fine as all it's
> doing is copying a still fairly low bitrate data stream from a PCI
> card to Ethernet.
>
> One problem I have is that it seems to be impossible to do wake on lan
> from suspended (S3) on the backend, probably due to 20th century
> hardware. So the backend does a normal shutdown when it's idle.Still
> it boots up mysqld and mythbackend in about 30s which isn't bad. It's
> just a shame that the frontend is ready before it.
>
> What would be REALLY nice is to run a kind of boss backend on the MSS
> which knows nothing about recording TV, but can serve mythweb and
> recordings to the frontend on demand. Then I would not have to wait
> for the real backend to wake up. This should surely be possible in
> 32MB RAM, though maybe a full MySQL database is too heavy for this
> task. Perhaps I could do some sort UPnP thing for this, and not bother
> with a myth frontend. I do all scheduling though Mythweb anyway, and
> the frontend is only used for viewing recodings.
>
> Hope this helps you see what's possible,.....

Wow, definitely.  I'm amazed at just how many people do this, and the 
varying methods in which they use it.  Actually, I shouldn't be so 
surprised with the flexibility of MythTV and Linux, but still... :)

I have taken a dump of the root filesystem of the only FE that I can 
tinker with without having my family lynch me and placed it in an 
NFS-exported area on my main file server.  I've also tweaked the tftp 
config so as to have a file for this particular MAC address.

I haven't begun to test anything yet, but a couple of questions come to 
mind:
How accurate is the wiki on this topic?
What, if anything, needs to be done to the NFS root volume's /etc/fstab?

Thanks!
-Rich


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