Are you receiving errors while editing the DNS Zone file in WHM ?

Error :
Editting zone domain.com
Unable to parse zone: Error while parsing zonedata for domain.com: expected valid serial, line 4 …propagated at /usr/local/cpanel/Cpanel/CPAN/Net/DNS/ZoneFile/Fast.pm line 142.

Solution :
Recreating the DNS zone file for the domain.com will fix this issue.

when some programs consume huge amount of virtual memory, make use of temporary SWAP space.
This can be achieved by mkswap  and swapon

* For EG: To have 64 MB extra swap space

dd if=/dev/zero of=/swapfile bs=1024 count=65535
mkswap /swapfile
swapon /swapfile

where “/swapfile” is the swap filename. The location of this file depends on the availabilty of File System’s Space and the write permission.

when you dont need this anymore, remove it using the following commands

swapoff /swapfile
rm /swapfile

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Error while sending mails from the Cpanel >> Squirrel Mail

Connection timed out
Server replied: 110 Can’t open SMTP stream.

Solution:
On shell, open this file
# vi /usr/local/cpanel/base/3rdparty/squirrelmail/config/config.php

CHANGE
$ useSendmail = false;

TO
$ useSendmail = true;

Save the file and the error is fixed.

MYSQLCHECK

The mysqlcheck client can be used to repair, check, optimize OR  analyze database tables. To perform these operations, mysqlcheck uses SQL statements REPAIR TABLE, CHECK TABLE, OPTIMIZE TABLE AND ANALYZE TABLE respectively.

AS MyISAM storage engine supports all these four statements, mysqlcheck can be used to perform these operations on MyISAM tables. This is not the case with the other storage Engines, hence may receive an  error like “The storage engine for the table doesn’t support check ”

The mysqlcheck performs the check or repair on the tables when the mysqld server is running ie you do not have to stop mysqld server to perform mysqlcheck.

Syntax :
mysqlcheck [options] [db_name [tbl_name, ..] ]

There are numerous options but the regular ones are:
Options :
•    –check, -c
Check the tables for errors. This is the default operation.

•    –analyze, -a
Analyze the tables.

•    –optimize, -o
Optimize the tables.

•    –repair, -r
Perform a repair that can fix almost anything except unique keys that are not unique.

mysqlcheck has a special feature compared to other client programs. The default behavior of checking
tables (–check) can be changed by renaming the binary. If you want to have a tool that repairs tables by
default, you should just make a copy of mysqlcheck named mysqlrepair, or make a symbolic link to
mysqlcheck named mysqlrepair. If you invoke mysqlrepair, it repairs tables.

The following names can be used to change mysqlcheck default behavior :

mysqlrepair   => The default option is –repair
mysqlanalyze  => The default option is –analyze
mysqloptimize => The default option is –optimize

Note : It is best to make a backup of a table before performing a table repair operation