Postings by James Pearson

Desktop lag with CentOS7/Mate and high CPU usage

We have noticed significant desktop/UI lag on CentOS7 workstations using
Mate when the CPU usage is high - i.e. the mouse pointer lags and moving
windows (e.g.

CentOS7/Mate Qt bugs/features?

We have recently migrated from CentOS6/Gnome to CentOS7/Mate - and have
noticed 'glitches' with some Qt applications that appears to be linked
to the 'org.mate.Marco.general' 'compositing-manager' setting - and
wondered how we 'fix' the issue ...

Below is a PyQT4 python script that shows the issues:


Next major version of Firefox on RHEL/CentOS ?

I know CentOS don't have inside info on what Redhat may or may not do in
the future - plus Redhat don't usually announce publicly what their
future plans are - but on the off-chance that someone on this list may know:

Does anyone know what Redhat are likely to do with the next major
release of Firefox on RHEL (and hence CentOS) ?

The reason I ask, is that RHEL has been supplying the 'ESR' (Extended
Support Release) version of Firefox - which Mozilla supports for about a
year - and RHEL moves to each new ESR version before Mozilla drops
support for the previous version.

Up until the cu

VirtualBox on CentOS 7 with bridged network not working

I've installed VirtualBox v5.2 on a CentOS 7.4 machine, but VMs set up
with bridged networking can not 'see' past the VirtualBox host machine


mate-terminal crash when using drag-n-drop tabs

We're using mate-terminal (1.16.3) from EPEL on CentOS 7.4 with the Mate
desktop, but mate-terminal crashes when we do the following:

Start mate-terminal, open a tab (File -> Open Tab) then with the left
mouse button drag a tab and drop it in the same terminal window - and
the terminal window crashes ...

I did a bit of Googling, and found this issue reported in earlier
releases of mate-terminal - which was fixed - but no mention of issues
with 1.16.x

However, if I rebuild and install the package from the mate-terminal
1.16.3 SRPM from EPEL, it doesn't crash ...

Which is rather bizarr

Adding new automount entries to a map served via sssd from AD

I've been experimenting with setting up a CentOS 7 client using
automount maps from Active Directory via sssd

I've followed the instructions given at:

<a href="" title=""></a>

and all works fine

However, I can't seem to make the client 'see' new map entries added to
the map on the AD server - I've tries reducing various timeout settings
in /etc/sssd/sssd.conf to see if that helps - e.g.

entry_cache_timeout = 60
entry_cache_autofs_timeout = 15

but map entries don't appear at all - unless I run 'sss_cache -A' to
invalidate the sssd autofs map caches


Error installing Nvidia driver on a 7.5 beta kernel

OK, I know CentOS has nothing to do with RHEL beta releases, but I
wanted to test if el7.5 has added support for a particular peripheral
(Wacom Pro 2 tablet) ...

XFS quota usage mismatch on CentOS 6 ?

We have a number of home directory servers running CentOS 6 exporting XFS file systems over NFSv3

We enable user quotas for all users - with a relatively small allocation to each user

Every now and then, we get a user that has a quota mismatch - where they are (usually) over their quota, but their actual usage (via du) is significantly less

This happens on any of the servers

I suspect that the mismatch is probably due to file space being allocated on the server, but somehow not referenced by a file - may be by deleted files?, but lsof on the client doesn't show any suitable deleted files

systemd services and Restart?

I've been trying out the Restart= option in some of my own systemd
service unit files - which appears to work fine

However, I notice that this option is only used in a few OS provided
service unit files - and was wondering about the wisdom of adding this
capability to other daemons/services? (e.g.

systemd order help?

I'm looking into 'porting' some custom init.d scripts that are in use on
CentOS 6 boxes for use on CentOS 7 using systemd

One particular init.d script needs to run after autofs has been started,
but before X11 is started

I'm guessing I could use something like:


Is this correct?

However, I would like to use the same systemd unit file on servers that
won't run X - will the above work?

Systemd and network startup/shutdown ?

I've just started to dip my toe in the water with CentOS 7 - and have
started looking at porting custom CentOS 6 init.d/xinetd/whatever
scripts and configs to systemd, but notice that CentOS 7 appears to use
/etc/rc.d/init.d/network as the method for starting/stopping the network

Is this correct - or am I missing something?


James Pearson

mod_clamav, apache and centos6?

I'm trying to get mod_clamav working with Apache on a CentOS 6.6 box -
without much luck ...

I'm using httpd 2.2.15-39.el6.centos.x86_64 with clamav
0.98.6-1.el6.x86_64 (from EPEL) and mod_clamav 0.23 compiled from source
via <a href="" title=""></a>

The mod_clamav source hasn't been updated in nearly 6 years - so may
well no longer work with more recent versions of Apache or Clamav ...

Before I spend too much time on this - I was wondering if anyone has
this set up working, or should I give up and try something else?


James Pearson

Active Directory, sssd and pam_cracklib?

I'm in the process of testing out sssd on a CentOS 6 install using
Active Directory for user authentication via sssd

All appears to be working fine - however, when I change a user password
using 'passwd' (or at login when the account has expired etc), it
appears pam_cracklib is being over-zealous with the new password

Active Directory is set up with a password policy - but pam_cracklib
(and may be other PAM modules?) have stronger password policies

So, I would like passwd to use the AD password requirements - and ignore
any pam_cracklib requirements

The password settings

Understanding RPM trigger scripts?

I'm trying to get my head around RPM trigger scripts - but currently
getting very confused ...

I have a custom RPM which has in its spec file a '%triggerin' script for
the 'kernel' RPM - i.e. a script that I want to run when the kernel RPM
is upgraded/installed

This works OK - once my custom RPM is installed, if the kernel is
subsequently upgraded/installed, my trigger script is run

However, the same trigger script is also run when I upgrade my custom
RPM - which I don't want - and so far, I can't find a reliable way of
making sure it isn't run in this case.

Writing to a symlink on a read-only file system that land on a read-write file system

We've come across a problem with 6.4 kernels that we didn't have with
6.2 kernels - which involves writing to a symlink that is on a read-only
file system - but the symlink lands on a read-write file system

The following shows the issue:

mkdir -p /mnt/tmp
mount -t tmpfs -o size=1% none /mnt/tmp
rm -f /tmp/file
ln -s /tmp/file /mnt/tmp/file
mount -o remount,ro /mnt/tmp
echo "some text" > /mnt/tmp/file

On a machine with a 6.2 kernel, the above works fine - the target of the
symlink (/tmp/file) is created etc.

Mounting USB drives read-only by default?

Is it possible to configure the automounting of USB drives to mount

Is there some gconf/udev/udisks/hal/whatever setting to alter the
default mount options when USB disks are plugged in by users?


James Pearson

Pulseaudio pauses when switching virtual terminal?

When using CentOS6/Gnome any audio playback will pause if I switch to
other virtual terminals - and resume when I switch back to X

Does anyone know if it is possible to configure pulseaudio (or some
other means?) to allow audio to continue playing when switching virtual


James Pearson

Wacom hotplug Xorg crash

We're seeing a number of Xorg crashes with CentOS 6.2 when using a Wacom tablet shared between two machines (the other machine is running Windows) via a KVM

Xorg crashes after switching the KVM back to the CentOS box

I've tried googling for this issue - and have found:

<a href="" title=""></a>

Which has a similar backtrace (although not identical) to ones we are seeing (see below) - but no further info is given on that webpage - but appears to indicated that more info might (?) be available if I have a Red Hat Subscription login - which I don't ...

Would it be

Missing /usr/share/X11/fonts/encodings/encodings.dir on CentOS 6 ?

I'm trying to work out if this is a bug or a feature of CentOS 6 ...

gdm in 6.2 missing keyboard menu?

I have a box running 6.0 that gives a keyboard layout menu via gdm when
logging in.

I've just installed a 6.2 box, but there is no keyboard layout menu

I've found a bugzilla entry at:


which says that with gdm in 6.2, it now only shows keyboard layouts
listed in /etc/sysconfig/keyboard

However, I've added a list of keyboard layouts as suggested by that BZ,
but I still don't get a keyboard menu.

Is there anything else I've missed?


James Pearson

CentOS6: installing 32bit and 64bit RPMS via the installer?

Installing 64bit CentOS6 only installs x86_64 and noarch RPMS - however,
I have a number of legacy 32bit apps that require a number of 32bit RPMS
to be installed.

Does anyone know how to get the installer to install the 32bit versions
of 64bit RPMS? i.e. in the way it does for CentOS5.


James Pearson

How and when are the sound modules loaded at system boot time on CentOS 5?

I've been trying to work out how the various sound modules get loaded at
boot time on CentOS 5 - but I can't find anything obvious under /etc/rc.d/

CentOS 4 did this in /etc/rc.d/rc.sysinit - but there is nothing
equivalent in CentOS 5

Does anyone know how these modules get loaded?


James Pearson

MegaRAID Storage Manager on CentOS 5.5?

Does anyone have the 'MegaRAID Storage Manager' GUI working on CentOS 5.5?

I can run it, but it won't let me log in.

The docs state that it requires the local root username and password -
but it always rejects this with "Message = Login failed: Invalid
username or password!"


James Pearson