The Raspberry Pi is a small Linux computer designed to help children learn programming. Being a full Linux System, it can also be used as a server or as the basis for various projects.
Here are some adjustments you might want to make to a new Raspberry Pi. The examples refer to a Raspberry Pi Model “B” bought from UK distributors New IT in February 2013. But they are pretty universal. Continue reading
Joomla, Drupal and WordPress are the world’s most popular blogging platforms. Right now I’m staring at the WordPress “Add New Post” page, because this blog is built on WordPress. WordPress is great. And incredibly slow.
This post appeared quickly in your browser ? Great. You have been served a page that was built several hours ago. Without the pre-fabricataion, you would have had a 5 or 10 second wait while WordPress created the page from scratch. Who waits 10 seconds for a page to load these days ? Nobody, that’s who. This post compares two WordPress caching plugins and finds that WP-Super-Cache is the best because of its ability to cache compressed pages. Continue reading
Having problems logging into WordPress ? It’s a tricky area, with a seemingly endless list of problems, causes and recommendations. In my case, the “login” link would hang before even asking for a user name or password. The browser window would eventually give up saying “no response from server”. The blog was up and healthy, but logging in as admin (or any other user) was not possible. Continue reading
In need of some network storage in the home ? Well, you could go off and buy a proper NAS unit, offering RAID, several Tb of storage, fast access speeds and so on. On the other hand, you might have something lying round the house that will do. It won’t be as good as a proper NAS, but it might just be good enough. Continue reading
This post may be of interest to UK users who own both a BT Home Hub 3 router and a WD TV Live media streamer. Both are Linux based systems, but getting one to work with the other can be a bit of a challenge.
The USB port on the back of the Home Hub 3 can be used to share storage over the network. Plug in a disk or memory stick, and it is automatically shared out as a windows share. Using a large capacity memory stick offers the possibility of NAS like, always-on access to your media files from any connected device. Low power consumption too. This post explains how access the USB connected drive from the WD TV Live. Continue reading
This is how to do a simple file system increase in Logical Volume Manager. For example, increasing /tmp from 512 Mb to 1 Gb.
/tmp is a logical volume:
# df -h /tmp
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vg00-tmpvol
496M 19M 452M 4% /tmp
Running “vgdisplay /dev/vg00” showed that volume group vg00 contained 3.5 Gb of free space. Extended the logical volume with lvextend: Continue reading
After a customer had performed some bad edits on various LDAP configuration files, users were locked out and unable to access the system. Root could still login however.
I logged in as root, and rather than mess with various config files, eg under /etc/pam.d, ran this command to disable LDAP authentication and enable “normal” authentication using /etc/shadow: Continue reading
Running sshd in the foreground can be an effective way to debug ssh problems. In the following example, a user was unable to access a remote system using ssh keys. Running sshd in debug mode provided a quick resolution. Both source and target systems were Solaris, but the same method applies equally to Linux. Continue reading
The Sheevaplug is a small ARM based “plug computer” manufactured by GlobalScale. This post explains how to connect over the serial connection for out-of-band access. A bit like connecting to the server processor of a unix server, or the alom/ilom of a Sun/Oracle box, or the Vsphere console of a vmware system.
Connect a USB cable from your PC to the sheevaplug’s micro USB port (also called the “JTAG” port) and proceed as below. Continue reading
Working on a client site recently, I noticed their Apache error log had grown to 32 Gb in size. The file was being written to at a rate of a quarter of a million lines a day, propelled by various cron jobs set up to run every 5 minutes. A PHP reconfiguration fixed the problem.
The box was a Solaris 10 system running “License Watcher“, and those messages was all coming from the License Watcher php code. Not genuine errors, just repeated diagnostics. I edited /usr/local/php/lib/php.ini and changed this line Continue reading