Sometimes there can be so many frozen mails in the Exim mail queue. To know the number of frozen mails in the mail queue, you can use the following command exim -bpr | grep frozen | wc -l In order to remove all frozen mails from the Exim mail queue, use the following command exim -bpr | grep frozen | awk {‘print $3’} | xargs exim -Mrm You can also use the command given below to delete all frozen mails exiqgrep -z -i | xargs exim -Mrm If you want to only delete frozen messages older than a day, you can try the following exiqgrepRead More →

If you run a replicated MySQL setup and have a master failure, you may see the following error in your error log. [ERROR] Error reading packet from server: Client requested master to start replication from impossible position ( server_errno=1236) At this point your slave will not be replicating and you will need to recover from the situation. But why did it occur in the first place and what does it mean to your data integrity? Why it occurs This error will occur if the master stops unexpectedly. This could be as a result of a hardware failure (like a disk error) or a power loss.Read More →

How to fix MySql Replication Error 1236 We have some websites that use two database servers in master-master replication. Recently one of the servers died and had to be resurrected. (They are cloud based and SoftLayer doesn’t seem to have their cloud-based offering thing nailed down, yet. Every week one of them will go down and be unresponsive until tech support does some magic.) After one of the servers was brought back up the other server would not connect. It “Slave_IO_Running: No” and “Seconds_Behind_Master: null” which means it was not playing nicely. First, I went to the MySql log files, which for this server isRead More →

When you connect your IPAD/IPHONE to the computer, you used to be able to see photos under DCIM folder , now it’s blank. It’s because your iphone is locked , this is to prevent someone copying your data when they don’t know your ipad/iphone password. How to fix? If your ipad/iphone is connected to the PC already , disconnect it. Unlock the phone connect to the PC again – make sure that your iphone/ipad is in unlock status.Read More →

When you finish installing Ubuntu , you see that there is no network card when running “ifconfig” , or checking /etc/network/interfaces , but you see there is no info for your network card. lspci -nn | grep -i net The following command will show a list of ethernet card available in your Ubuntu box. The output may look like this 09:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5761e Gigabit Ethernet PCIe (rev 10) If you see the result, that means the network card has been recognized by your OS , then you just need to configure it you can add these line to bring that interfaceRead More →

if you have ConfigServer Security & Firewall enabled in WHM , only a certain ports are allowed to come in/out. By default mysql will be blocked, to unblock it you need to add 3306 as an allowed list Go to ConfigServer Security & Firewall – > Firewall Configuration -> Add 3306 into TCP_IN list ( separated by comma) like this: 20,21,22,25,53,80,110,143,443,465,587,993,995,2077,2078,2082,2083,2086,2087,2095,2096,3306Read More →

If this is an existing users Syntax: usermod -a -G groupname username For example: usermod -a -G sudo myadminaccount -> this will make myadminaccount belong to sudo group , this mean it can run sudo su – to becom a root. For new user ( you haven’t created it yet) Syntax: useradd -G groupname username This will add a new username to a group name groupnameRead More →