≡ Menu

Troubleshooting Unix / Linux Servers

Troubleshooting tips about Linux, *BSD, UNIX, Apple OS X, programming and MS-Windows servers and desktop systems ( rss feed ).

HowTo: Check Swap Usage in Linux

How do I check swap (paging) usage under Linux operating systems using command bash/ksh line options?
[click to continue…]

One of my php script called setoptions.php is hosted on my new vps server. However, it is not working so I setup php error log as described here and, and I see the following warning repeated in my log file:

PHP Warning: fread(): Length parameter must be greater than 0 in /var/www/html/scripts/setoptions.php on line 311

The line no # 311 is as follows in my php script:
$fname = 'myappconfig.php';
$content = fread($fhandle,filesize($fname));

How do I fix this problem under Unix/Apache/php5 server?
[click to continue…]

How do I find out my SATA link speed? How do I make sure my sata hard disk is working at 6Gbps speed and how do I verify this on a Linux server running on HP or IBM amd64 hardware?
[click to continue…]

How do I list or display all processes, executables, and shared libraries that are using up all virtual memory under Debian or Ubuntu Linux server for troubleshooting purpose?
[click to continue…]

I'm running PHP version 5.3.3 on CentOS / RHEL 6.x with APC php-pecl-apc-3.1.9. However, I'm getting the following warnings in my php server log file:

[01-Jul-2012 10:50:49] PHP Warning: require_once(): Unable to allocate memory for pool. in /var/www/html/includes/admin.php on line 57
[18-Jul-2012 17:00:08] PHP Warning: include_once(): Unable to allocate memory for pool. in //var/www/html/includes/xmlrpc.php on line 55
[18-Jul-2012 17:00:40] PHP Warning: require(): Unable to allocate memory for pool. in /var/www/html/includes/geshi.php on line 2307

How do I fix these php warnings?
[click to continue…]

When I ssh into my server and login as t root user and I'm getting the following error on screen:

Could not chdir to home directory /root: No such file or directory

How do I fix this error under CentOS or Debian Linux server?
[click to continue…]

I'm trying to run an application and getting the following error on screen:

error while loading shared libraries: libgobject-2.0.so.0

How do I fix this problem under Debian or Ubuntu 64 bit (amd64) Linux?
[click to continue…]

I'm using NVIDIA UNIX x86_64 Kernel Module version (driver) 280.13 under Debian 64 bit Linux with Linux kernel 2.6.32-5-amd64 x86_64. However, I'm getting the following errors in my /var/log/messages file

Feb 13 05:53:39 wks01 kernel: [26652.425207] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 14 03:59:14 wks01 kernel: [39846.244283] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 17 04:47:32 wks01 kernel: [35237.485871] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 18 06:53:19 wks01 kernel: [49298.937949] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Feb 19 06:14:01 wks01 kernel: [28508.567838] NVRM: GPU at 0000:01:00.0 has fallen off the bus.

This error occurs randomly and my laptop goes in hard freez mode. The hard reboot is the only way to recover from complete freeze of my Dell M6500 Debian Linux based laptop. How do I fix this problem?
[click to continue…]

I'm running the Mediawiki software under Apache web server running on the Unix operating systems. I'm getting the following in my php error log:

PHP Fatal error: Cannot redeclare wfProfileIn() (previously declared in /var/www/html/wiki/includes/profiler/Profiler.php:14) in /var/www/html/wiki/includes/ProfilerStub.php on line 25.

How do I fix this problem under Mediawiki version 1.18.0?
[click to continue…]

Linux: Neighbour Table Overflow Error and Solution

I setup a CentOS Linux based Linux server running as a gateway and firewall server. However, I'm getting the following messages in the /var/log/messages log file:

Dec 20 00:41:01 fw01 kernel: Neighbour table overflow.
Dec 20 00:41:01 fw01 last message repeated 20 times

OR


Dec 20 00:41:01 fw03 kernel: [ 8987.821184] Neighbour table overflow.
Dec 20 00:41:01 fw03 kernel: [ 8987.860465] printk: 100 messages suppressed.

Why does kernel throw "Neighbour table overflow" messages in syslog? How do I fix this problem under Debian / CentOS / RHEL / Fedora / Ubuntu Linux?
[click to continue…]