nfsd open file limits

Recently I came across a user who requested an increase to the ulimit settings for nfsd kernel processes.

root      1122  0.0  0.0      0     0 ?        S    11:43   0:00 [nfsd]

# grep 'open file' /proc/1122/limits
Max open files            1024                 4096                 files

This appears to default to 1024/4096 soft/hard.

As you can see from the brackets surrounding nfsd, this is a kernel process spawned from kthreadd and thus won’t inherit limits from systemd (or limits.conf)

I decided to throw together a quick C++ program proving that these limits do not impact how many open files a client can utilize.

#include <iostream>
#include <fstream>
#include <dirent.h>
#include <chrono>
#include <thread>

using namespace std;
int main() {
        DIR *dir;
        struct dirent *entry;
        string filename;

        dir = opendir(path);
        std::fstream fs[8194];
        int count = 0;


        while ((entry = readdir(dir)) != NULL) {
          printf("  %s\n", entry->d_name);
        return 0;

On the NFS server in question, I created 8192 files.

[[email protected] export]# for x in {1..8192}; do touch $x; done

I also ensured that only 1 [nfsd] thread was running (to rule out the open files being split between multiple nfsd threads).

On the client I made sure the user had appropriate ulimit settings

# ulimit -n

Then I ran the above program to hold open all 8192 files. As you can see below, there was no problem doing so.

# lsof +D /export/ | wc -l

Tested with NFSv3 (with lockd) and NFSv4.

Conclusion: The [nfsd] limits shown in /proc has no impact on the nfs clients.

Bluetooth headset with Qubes

NOTE: This was done with a bluetooth USB adapter. If you use your wireless card’s built in bluetooth you should be able to do the same, you’ll just need to do it on sys-net instead of a seperate qube

First, create a fedora ‘bluetooth’ qube that we will attach the USB adapter to

Install required packages:

# dnf install blueman udev-x11 

Add the following to /etc/pulse/ where is your qube network (if different)

load-module module-bluetooth-discover
load-module module-native-protocol-tcp auth-ip-acl=, auth-anonymous=1

Add user to audio group

# usermod -a -G audio user

Create /etc/systemd/user/pulseaudio.service

 [Unit] avahi-daemon.service
 Description=PulseAudio Sound System

 ExecStart=/usr/bin/pulseaudio -vv
 ExecStop=/usr/bin/pulseaudio --kill


Reload systemd (or just reboot)

# systemctl daemon-reload 

As user, enable it so pulseaudio is running at startup

# systemctl --user enable pulseaudio.service 

Create a script to handle the blueman-applet in /root/

while [ true ]; do
   sudo -u user blueman-applet
   sleep 1

Make it executable

# chmod +x /root/

Add the following to /rw/config/rc.local

iptables -I INPUT -s <CLIENT IP> -j ACCEPT
/root/ &

Add firewall rule on sys-firewall qube in /rw/config/qubes-firewall-user-script


On each client, add the following to /etc/profile to ensure your applications use your bluetooth qube for audio


Now when you attach the USB bluetooth adapter to the bluetooth qube the applet should appear and you’re good to go.

Increase stripe_cache_size for mdadm/md devices permanently

Create /etc/udev/rules.d/60-md-stripe-cache.rules

SUBSYSTEM=="block", KERNEL=="md*", ACTION=="change", TEST=="md/stripe_cache_size", ATTR{md/stripe_cache_size}="16384"

Reload udev rules, will take effect immediately.

udevadm control --reload-rules

udevadm trigger

Confirm (where md0 is your md device in question)

cat /sys/devices/virtual/block/md0/md/stripe_cache_size

Cisco IOS Import UCC Certificate

This assumes you have already requested and received your UCC certificate (IIS/Apache/etc.)

crypto ca trustpoint godaddy
enrollment terminal
chain-validation stop
revocation-check none

crypto ca authenticate godaddy
Root Godaddy CA Cert (gd-class2-root.crt)

!Intermediate trustpoint
crypto ca trustpoint intermediate-primary
enrollment terminal
chain-validation continue godaddy
revocation-check none

crypto ca authenticate intermediate-primary
This is the first file inside the PFX container (gd-g2_iis_intermediates​)

crypto ca trustpoint intermediate-secondary
enrollment terminal
chain-validation continue intermediate-primary

crypto ca authenticate intermediate-secondary
This is the second file inside the PFX container (gd-g2_iis_intermediates)

crypto pki import godaddypriv pkcs12 tftp: password PASSWORDHERE
#pkcs12 you export from Windows

crypto pki trustpoint intermediate-secondary
rsakeypair godaddypriv

crypto ca import intermediate-secondary certificate
This should be the CRT godaddy gave you, the file you import into IIS

Vostro 1400 Issues Fixed in Ubuntu Hardy 8.04

I installed Alpha 5 of Ubuntu Hardy 8.04 and have had VERY possitive results.

Fixed issues are:


After some time my laptop’s fan would turn on and off (from i8k’s 1 setting to 2) whether i8k was loaded or not (i8k would not load without force=1). It did this constantly and was very loud.

This behavior started after many kernel upgrades of 7.10. 8.04 Alpha 4 also had this problem.

The issue seems resolved; my fan stays at setting 1 (fan on low speed). I have not heard it go to setting 2 (high speed) yet, but my laptop does not usually run hotter than 40oC.

Update: i8k does not allow you to turn the fan to the second setting; the hardware seems to control when the fan is turned on high. I notice that the fan seems to respond more to the GPU’s temperature than the CPUs temperature. CPU is usually less than 40oC however, so I’m not concerned.


This was a major issue with Ubuntu. 7.10 required an option in /etc/modprobe.d/alsa-base (model=3stack). 8.04 did not work at all (I filed a bug report in launchpad that solved this issue).

This latest Alpha fixed the issue.


I have a  GeForce 8400M GS. 7.10 had issues with my card (some kernels could not handle ‘nvidia’ and I had to settle for ‘nv’). Compiz had very strange bugs too (windows could glitch up, lots of twitching when maximizing windows).

8.04 has resolved these issues (for now). Compiz is working beautifully for the first time, and ‘nvidia’ is loaded without issue.

LCD Lid stays on when closed

I noticed recently that the LCD stays on after I close the lid of my laptop. This is a waste of power, and causes the laptop to run hotter than it should.

Edit /etc/acpi/ and add the following line after /usr/share/acpi-support/screenblank

xset dpms force off