Skip to main content

Talking about backups

Who needs backups?

My parents went on a holiday to Europe last year. My father had a new Digital SLR and on the last day in Italy, just before they were about to return to Australia, it was stolen. If he had backed up his photos on to a laptop, for example, he would have them now. The camera is replaceable but the photos were not.

I am sure everyone has a story about lost data.

Everyone needs backups.

So how can you backup a file server when the amount of data far exceeds any backup media you can afford?

Get a second file server?

In my case I make sure the stuff I do not want to lose is backed up. Pictures, media that would be hard to replace or take a lot of effort and time to reproduce (I spent nearly a year converting LPs - vinyl - to digital form) and scanned documents are all backed up to external disks and onto DVDs.

I think my family have the message now. One of my sisters has bought a 1TB external drive and a 320GB portable disk for off site backups. My mother has a 500GB external drive. Now what they need is a backup strategy.

Several weeks ago one of the disks in my file server failed. It took several days to get a replacement and during that time the RAID-5 ran in degraded mode. I have now added a hot spare so if one drive fails it will automatically switch to using the spare. I also have a cold spare available. As long as there is no fire!

Comments

Popular posts from this blog

The Extended Attributes Are Inconsistent in Windows 8

I have upgraded my laptop to Windows 8 and all was fine for about three hours and then I started to get an error when trying to run any application that required Administrator privileges. Half an hour of Googling led me to this blog post   Case of the broken uac prompt This problem was caused by downloading themes. The final theme I had decided on included a new sound theme. Clearly at least one of the sounds did not play (the one for the UAC prompt!). Changing the sound theme (right click on desktop, choose "personalisation") to Windows Default sorted out the problem. Doing a clean install would also have fixed it but that would have been a drastic solution and as soon as I installed a new theme it may have happened again.

Beware vnc and upnp

My new linux box got hacked yesterday. I was careless. My ADSL router has upnp support and it is turned on by default. I enabled "Remote Desktop" in Linux - which is a version of vnc - and decided not to set a password as it would not be accessible from outside the local network. That was my first mistake. Last night I noticed a second connection to the linux box. Someone was using the browser and had connected to Western Union and was trying to install the flash plugin. They had not got very far as Fedora 14 does not install Flash on a 64bit system as it is still in beta so the install is not straightforward. I was able to disconnect this errant person before they got any further and I then disconnected the ADSL line from the modem to prevent another attempt and proceeded to diagnose what had happened. I checked the preferences for VNC and noticed the automatically configure the network check box had been selected and that it was reporting an external address could be

"No child processes" error on Linux

A problem was reported by a customer. They were getting a failure and in the logs it reported error → waitpid failed 'Reason: No child processes' The “No child processes” error came from waitpid() after using  fork/spawn to launch a utility to load data into a data base. Upon detailed investigation it appears it is possible that some other process that the user is running has changed the default handler for SIGCHLD - possibly the shell (e.g. bash!) used to launch our server processes. If the signal handler is set to SIG_IGN then when a process is started using fork()/exec() the return code from the process is NOT returned and waitpid() cannot retrieve the response code. The most likely reason for "No child processes" error from waitpid() is that the signal handler for child processes (SIGCHLD) is not set to SIG_DFL. This should not be possible however it seems that on Linux a process run in the shell (or maybe a shell process) can set it