File Serving: Sheevaplug vs Pi vs WDTV vs Linkstation vs Home Hub 3

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

Mounting BT Home Hub 3 USB on WD TV Live

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

Resizing /tmp on Red Hat 5.3 (ext3, LVM)

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

How to disable LDAP Authentication in Linux

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

SSH Authentication and Directory Permissions

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

Connect to Sheevaplug USB from Red Hat Linux

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

Quick Script to Find Duplicate Files

Here’s a quick script to show duplicate files on Linux. It should cope with arbitrary spaces in file names, and to save time and CPU resources, it will checksum only files of the same size.

Usage: Save the script to dups.sh or whatever, then run it with no arguments. A list of duplicated files is output.

Continue reading

Recovering Data from a Corrupted SD Card

SD cards are used in digital cameras, phones and other devices, where their speed and large capacity makes them useful for storing pictures, video and other voluminous multi-media items. It is quite common these days for a mobile device to contain a 16 Gb or 32 Gb SD card.

With the devices being so mobile, backups are easily overlooked. And it is quite easy for an SD card to become corrupted, for example if the card is removed while the device is on, or the battery is taken out while a video is being shot.

I was given a corrupted 16 Gb card and asked to recover the files, if possible. The rest of this post explains how the data was safely restored using simple Linux tools. Continue reading