I-Learnings

Unable to start MySQl

2011-04-06T17:38:00.000-07:00

We are not able to start MySQL because of the error below.

110407 00:32:13 mysqld started
110407 0:32:14 InnoDB: Error: cannot allocate 3221241856 bytes of
InnoDB: memory with malloc! Total allocated memory
InnoDB: by InnoDB 37679104 bytes. Operating system errno: 12
InnoDB: Check if you should increase the swap file or
InnoDB: ulimits of your operating system.
InnoDB: On FreeBSD check you have compiled the OS with
InnoDB: a big enough maximum process size.
InnoDB: Note that in most 32-bit computers the process
InnoDB: memory space is limited to 2 GB or 4 GB.
InnoDB: We keep retrying the allocation for 60 seconds...
InnoDB: Fatal error: cannot allocate the memory for the buffer pool
110407 0:33:17 [ERROR] /usr/sbin/mysqld: Can't find file: './mysql/host.frm' (errno: 13)
110407 0:33:17 [ERROR] /usr/sbin/mysqld: Can't find file: './mysql/host.frm' (errno: 13)
110407 0:33:17 [ERROR] Fatal error: Can't open and lock privilege tables: Can't find file: './mysql/host.frm' (errno: 13)

I tried to remove the /etc/my.cnf. Always remember to back up the file first :). When i tried to start again the MySQL service still getting the errors. I tried to find some solutions in the web but i cannot find any related problems. I tried to set again the mysql configuration file. And when i tried to start MySQL and kaboom it started. hehehe.. I don't know why but i am able to start the MySQL :)

When i was starting the server i am seeing some weird logs before the MySQl started.

[root@TESTING01 etc]# service mysql start
/usr/bin/my_print_defaults: unknown option '--use-mysqld_safe'
/usr/bin/my_print_defaults: unknown option '--use-mysqld_safe'
Starting MySQL...... [ OK ]
[root@TESTING01 etc]# tail -f /var/lib/mysql/

PHP Compilation Errors and Solutions.

2008-07-25T00:51:00.000-07:00

Additional solutions. Previously i posted some solutions regarding some errors in compiling PHP from source. Some errors below were posted in my previous postings.

---------------------------
checking for bison version... invalid
configure: warning: bison versions supported for regeneration of the Zend/PHP parsers: 1.28 1.35 1.75 1.875 2.0 2.1 2.2 2.3 (found: none).
checking for flex... lex
checking for yywrap in -ll... no
checking lex output file root... ./configure: line 3276: lex: command not found

solution: flex-2.5.4a-33.i386.rpm
---------------------------
checking whether to enable LIBXML support... yes
checking libxml2 install dir... no
checking for xml2-config path...
configure: error: xml2-config not found. Please check your libxml2 installation.

solution: libxml2-devel-2.6.16-6.i386.rpm
---------------------------
checking whether to enable JIS-mapped Japanese font support in GD... no
checking for fabsf... yes
checking for floorf... yes
configure: error: libjpeg.(a|so) not found.

solution:libjpeg-devel-6b-33.i386.rpm
---------------------------

checking for jpeg_read_header in -ljpeg... yes
configure: error: libpng.(a|so) not found.

libpng-devel-1.2.7-1.el4.2.i386.rpm
---------------------------
checking for png_write_image in -lpng... yes
If configure fails try --with-xpm-dir=
configure: error: freetype2 not found!

Solution: up2date freetype-devel
---------------------------

checking for LDAP support... yes, shared
checking for LDAP Cyrus SASL support... no
configure: error: Cannot find ldap.h

solution: up2date openldap-devel
---------------------------

Setting a UTC Timezone

2008-05-16T05:39:00.000-07:00

What timezone should you use for your server? Perhaps you should try Universal Co-ordinated Time (UTC).

vi /etc/sysconfig/clock and change the UTC line to: "UTC=true"

Set localtimezone to UTC: ln -sf /usr/share/zoneinfo/UTC /etc/localtime

If you want to set your timezone to something else, perhaps your personal timezone, then you find that timezone under /usr/share/zoneinfo and link that to /etc/localtime. For example: ln -sf /usr/share/zoneinfo/Australia/Brisbane /etc/localtime.

How to get and install Apache in Linux

2008-02-19T11:06:00.001-08:00

1. Get the latest Apache distribution at http://www.apache.org

2. Download and save it to /home/someuser/source/

3. Open terminal

4. # cd /home/someuser/source/

5. Unpack the distribution

· # tar xzvf httpd-x.x.x tar.gz

6. Go to the Apache source directory

· # cd httpd-x.x.x

7. Configure, compile and install Apache

· # ./configure --prefix=/usr/local/apache --enable-module=all --enable-shared=max

· # make

· # make install

How to use crontabs

2008-02-12T23:13:00.000-08:00

Crontab Commands
__________
export EDITOR=vi ;to specify a editor to open crontab file.

crontab -e Edit your crontab file, or create one if it doesn't already exist.
crontab -l Display your crontab file.
crontab -r Remove your crontab file.
crontab -v Display the last time you edited your crontab file. (This option is only available on a few systems.)

Crontab syntax :-
A crontab file has five fields for specifying day , date and time followed by the command to be run at that interval.

* in the value field above means all legal values as in braces for that column.
The value column can have a * or a list of elements separated by commas. An element is either a number in the ranges shown above or two numbers in the range separated by a hyphen (meaning an inclusive range).

Note: The specification of days can be made in two fields: month day and weekday. If both are specified in an entry, they are cumulative meaning both of the entries will get executed .

Crontab Example

A line in crontab file like below removes the tmp files from /home/someuser/tmp each day at 6:30 PM.

30 18 * * * rm /home/someuser/tmp/*

Below runs the script every 3 minutes.

*/3 * * * * /home/perl/update.pl

Disable Email

By default cron jobs sends a email to the user account executing the cronjob. If this is not needed put the following command At the end of the cron job line .

>/dev/null 2>&1

How to install JDK 6 Update 4 in RHEL 4/5

2008-02-08T01:31:00.000-08:00

STEP 1:DOWNLOADING FILE
Download Linux RPM in self-extracting file from http://java.sun.com/.

jdk-6u4-linux-i586-rpm.bin - for non 64 bit computer
jdk-6u4-linux-x64-rpm.bin - for 64 bit computer

STEP 2: HOW TO INSTALL

chmod a+x jdk-6u4-linux-xxxx.rpm.bin
./ jdk jdk-6u4-linux-xxxx.rpm.bin
Remove the existing java installation. you can identify the package by executing 'rpm -qa | grep java' you can remove the package by executing rpm -e 'java-1.x.x.'
rpm jdk-6u4-linux-xxxx.rpm
vi /root/.bash_profile and add this ..
PATH=$PATH:$HOME/bin:/usr/java/jdk1.6.0_04/bin

After doing the steps reboot your machine.

PHP Compilation Error: configure: error: Cannot find rfc822.h. Please check your c-client installation.

2008-02-08T01:08:00.000-08:00

If you are getting this error while compiling the PHP source, this is how to fix the problem.

Solution: If your machine is registered to redhat network just execute up2date -i libc-client-devel to install in your machine

If your machine is not registered download the libjpeg-devel.x.x.x.rpm then install it your machine.

rpm -ivh libc-client-devel.x.x.x.rpm

PHP Compilation Error: lib64/libc-client.a: could not read symbols: Bad value | make: *** [ext/imap/imap.la] Error 1

2008-02-08T00:59:00.000-08:00

/usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../../../lib64/libc-client.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
make: *** [ext/imap/imap.la] Error 1

If you are getting this error, you can fix this by installing an older version of the following rpm's below.

libc-client.x.x.x.rpm
libc-client-devel.x.x.x.rpm

Some older php-source is not compatible with the latest libc-client.

I don't know if this is the ultimate solution but it works when I tried to install the older version of libc-client. =-)

PHP Compilation Error: configure: error: libjpeg.(a|so) not found.

2008-02-08T00:07:00.000-08:00

If you are getting this error while compiling the PHP source, this is how to fix the problem.

Solution: If your machine is registered to redhat network just execute up2date -i libjpeg-devel to install in your machine

If your machine is not registered download the libjpeg-devel.x.x.x.rpm then install it your machine.

rpm -ivh libjpeg-devel.x.x.x.rpm

Sendmail error:unqualified host name (localhost) unknown; sleeping for retry

2007-07-19T15:36:00.000-07:00

Solution:Make sure the host's names (including localhost) are
defined in /etc/hosts, and that /etc/hosts is being used in
name resolution.

Possible Fixes:
The solution will fix in shortening waiting time execution
of mailq,sendmail -q, and restarting the service of sendmail.