Mounting NFS at fluksometer.

I'd like to mount a NFS export on the Fluksometer to overcome capacity limitations. But I've had no success doing so, anyone doing this already?

I've installed and loaded the NFS kernel module (kmod-fs-nfs if I remember correctly). But when I try to mount with 'mount.nfs' the Flukso becomes unreachable, and sometimes reboots. To bring it back I need to power-cycle the Fluksometer.

I do see the mount request coming in at my server in the syslog. Any ideas?

gonium's picture


on my Flukso I have about one Megabyte of RAM left when it is running. Have you monitored the memory consumption? Probably the Linux kernel runs out of memory and starts to kill processes :-)


yschaeff's picture

Hmm, not looked in to that actually. If that is the problem I might try to reduce the ramdisk, which is less important when I manage to set up NFS. Thanks.

icarus75's picture

Could you share the exact commands you've used to download/install the NFS kmod? I could try to replicate it at my side.

'Free' memory is memory that's not being wasted by the kernel on caches and memory buffers. Here's a dump of the free command on my Fluksometer right after startup:

  1. root@flukso:~# free
  2.               total         used         free       shared      buffers
  3.   Mem:        13764        11976         1788            0         1388
  4.  Swap:            0            0            0
  5. Total:        13764        11976         1788

I then ask the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free.

  1. root@flukso:~# echo 3 > /proc/sys/vm/drop_caches
  2. root@flukso:~# free
  3.               total         used         free       shared      buffers
  4.   Mem:        13764         7292         6472            0          124
  5.  Swap:            0            0            0
  6. Total:        13764         7292         6472

If I recall correctly from the load tests, the kernel needs a minimum of 500-700k RAM before it starts to kill processes. So we actually have about 5.5M of RAM memory available.

yschaeff's picture

This is an approximation of the commands:

  1. opkg update
  2. opkg install kmod-fs-nfs
  3. insmod nfs
  4. mount.nfs /mnt
  5. -crash-

When I drop the caches as you suggested I have about 5.8 MB available. The Flukso still becomes non responsive at a mount however.

Last night I tried to reduce the ramdisk size in /etc/preinit. It seems that my changes there are ignored, although saved between boots. I'm not familiar enough with OpenWRT to grasp the programflow at bootup, but it seems the file is also on a ROM. Would I need to reflash the device to make this change?

icarus75's picture

Kernel packages don't seem to be very portable, even when built for identical Linux versions. I've compiled the packages you require within my Flukso build environment. They're available here and here. They Just Work(TM).

If you want to compile other packages or even the entire image, you should have a look at this forum post.


yschaeff's picture

Hi thanks for your reply (message edited),

We got it working for wouter's flukso. Mine is currently in a undefined state but too far away to give it a reboot at the moment. We need to find out whether mine is b0rked or we just did something wrong.

Wouters Flukso works with both your precompiled packages and our own compiled packages.

update 20091124 My Flukso works as well with NFS now. :D