Posts Tagged ‘servers’

For a few years now I keep catching myself transferring files between Linux servers, in a silly way… What I mean is using somthing like ftp, or copying to my desktop and then up to the other server – all hassle (and in the case of ftp – inherently insecure).  Why do I do this? [...]

Had a problem earlier this week, webmail couldn’t always send e-mail. It was coming back with the following error:

SMTP Error: SMTP error: Connection failed: Failed to connect socket: Connection timed out.

Have you ever had a linux server or desktop which all of a sudden couldn’t create a file – running “df -h” shows you your disk partitions aren’t full?

You’ve logged in as root to check – and yup you still can’t write any files – even a “touch test.txt” fails with a message saying can’t write file – disk or partition full?

You can remount a linux system on the fly like this:-

umount tmpfs

The Cpanel system has a feature to migrate accounts from another server – be it Cpanel or another webhosting panel – this often works, recently though I’ve had a problem with using it for Cpanel to Cpanel where it would connect but fail to transfer the backup file.

Those of you with Exim will sometimes needs to do some work on it – here’s a list of the commands which I find most useful: If you want to see what exim is doing right now : “exiwhat” if you think you have queue problems then you can print a countof messages in the [...]

Another of the most useful tools in server administration is the Crontab – you use this to schedule jobs (programs) to run at regular intervals. These tasks can be  varied, from restarting servers, services – creating files, changing permissions, runing batch programs, deleting files etc… Of course sometimes crontab is not the best solution as [...]

Grep is a tool that is used often by system administrators – including myself, however I often have to double check the syntax online – as a result this post is to help me find out how and you of course. first I recommend to change to the directory that you think or know the [...]

I realised after my previous post I realised that it would be worthwhile talking about adding a new partitition.

The first thing you need – or I assume – is that you have a separate hard-drive which is not active (mounted) or can be unmounts using the standard umount command.

We assume the device is sdc (it could be sdb, sda, hda1 etc..).

We had a problem on one of the servers which I help administer. Every now and again RAM usage would max out and SWAP would then be used – this would sometimes max out and bye bye server, normally this happened for only a few seconds and all was fine – however if it lasted more then when SWAP ran out – the server ground to a halt and needed a manual restart.

The server in question is quite busy – but only had 512Meg of RAM (this has since been rectified) historically as it wasn’t that busy at first several years ago has slowly grown as websites on it have grown in popularity and databases have grown.

So an immediate fix was required