Hi I have a mythbackend with the following configuration:
Asus P3CLS server motherboard
1ghz Pentium 3 processor
Integrated Intel 10/100 network card
4 IDE Maxtor 7200 udma 66 drives
256 rdram memory
No soundcard
agp graphics card for troubleshooting not used for frontend
3 pcHDTV cards
2 Happaugge PVR 250

Running knoppmyth RD51 (it is supposed to be the leanest mythtv installation and is myth .19)

I have multiple frontends, connected via a cisco switch.

For example one is the following:

MSI RS480mil
AMD 64 3200 Venice
Nvidia 5300 pcx
80 gig UDMA 100 IDE drive
1gig ddr667 dual channel memory
10/100/1000 integrated networking
Knoppmyth RD51

I have a lot of issues with the frontends crashing. Locking up to the point I cannot SSH in or kill gdm. I have to physically reboot the machine. The Backend doesnt seem to crash.

In the logs I get alot of errors, that appear to be memory related. The backend has only 256 megs of memory but that is RDRAM.. I have read that Isaac uses 256 as the reference platform. I really don't want to get more memory for the backend because RDRAM is expensive and its a $250 guess to do that.

Here is top with no shows running. I am using swap and alot.

top - 21:09:32 up 3 days, 4:20, 2 users, load average: 0.16, 0.12, 0.09
Tasks: 102 total, 3 running, 99 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0% us, 0.7% sy, 0.0% ni, 99.0% id, 0.0% wa, 0.0% hi, 0.3% si
Mem: 253272k total, 244500k used, 8772k free, 31616k buffers
Swap: 385552k total, 200600k used, 184952k free, 121792k cached

DMESG output:

BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000000fffc000 (usable)
BIOS-e820: 000000000fffc000 - 000000000ffff000 (ACPI data)
BIOS-e820: 000000000ffff000 - 0000000010000000 (ACPI NVS)
BIOS-e820: 00000000ffff0000 - 0000000100000000 (reserved)
0MB HIGHMEM available.
255MB LOWMEM available.
On node 0 totalpages: 65532
DMA zone: 4096 pages, LIFO batch:0
Normal zone: 61436 pages, LIFO batch:15



mythbackend logs
2006-12-31 09:51:46.186 MainServer::HandleAnnounce Playback
2006-12-31 09:51:46.188 adding: mythtvfamilyfrontend as a client (events: 0)
2006-12-31 09:51:46.253 TVRec(5): Changing from None to WatchingLiveTV
2006-12-31 09:51:47.381 MainServer::HandleAnnounce Playback
2006-12-31 09:51:47.388 adding: mythtvfamilyfrontend as a client (events: 0)
2006-12-31 09:51:47.395 MainServer::HandleAnnounce FileTransfer
2006-12-31 09:51:47.400 adding: mythtvfamilyfrontend as a remote file transfer
2006-12-31 09:51:47.800 TFW, Error: Write() -- IOBOUND begin cnt(188) free(111)
2006-12-31 09:51:47.815 TFW, Error: Write() -- IOBOUND end
2006-12-31 09:51:48.037 TFW, Error: Write() -- IOBOUND begin cnt(188) free(111)
2006-12-31 09:51:48.043 TFW, Error: Write() -- IOBOUND end
2006-12-31 09:51:48.075 TFW, Error: Write() -- IOBOUND begin cnt(188) free(67)
2006-12-31 09:51:48.080 TFW, Error: Write() -- IOBOUND end
2006-12-31 09:51:48.089 TFW, Error: Write() -- IOBOUND begin cnt(188) free(23)
2006-12-31 09:51:48.095 TFW, Error: Write() -- IOBOUND end
2006-12-31 09:51:48.118 DVB#2 DVB SI Table Parser Started
2006-12-31 09:51:48.222 Finished recording Today: channel 1041
2006-12-31 09:51:48.490 scheduler: Last message repeated 2 times: Finished recor
ding: MAD TV: channel 1051

and some more

2006-12-31 11:00:02.851 TVRec(5): RingBufferChanged()
2006-12-31 11:00:02.869 Finished recording The Littles "The Rats Are Coming": ch
annel 1111
2006-12-31 11:00:02.859 AFD: Opened codec 0x81c6220, id(AC3) type(Audio)
2006-12-31 11:00:02.976 AFD: Opened codec 0x821df00, id(AC3) type(Audio)
2006-12-31 11:00:03.090 NVP: Recording does not have position map.
Run 'mythcommflag --file 1111_20061231104553.mpg --rebui
ld' to fix
2006-12-31 11:00:03.311 MainServer::HandleAnnounce Playback
2006-12-31 11:00:03.314 adding: mythtvfamilyfrontend as a client (events: 0)
2006-12-31 11:00:03.322 MainServer::HandleAnnounce FileTransfer
2006-12-31 11:00:03.329 adding: mythtvfamilyfrontend as a remote file transfer
2006-12-31 11:03:44.063 TVRec(5): Changing from WatchingLiveTV to None
2006-12-31 11:03:44.704 Finished recording Liberty's Kids "Common Sense": channe
l 1111
2006-12-31 11:03:44.825 scheduler: Last message repeated 3 times: Finished recor
ding: The Littles "The Rats Are Coming": channel 1111
2006-12-31 11:03:44.834 scheduler: Finished recording: Liberty's Kids "Common Se
nse": channel 1111
(END)


root@mythtvmasterbackend:~# free -m
total used free shared buffers cached
Mem: 247 238 8 0 31 118
-/+ buffers/cache: 88 158
Swap: 376 195 180

I upgraded to RE50 and it is using alot less memory. I will report back if I am still experiencing errors.

Does anyone run a backend only with 256megs of memory with no issues?