Wednesday, 7 October 2009

Scheduling backups

In Gina Trapani's excellent HowTo backup at she suggests 3 folders, one backing up (same files to different folders) nightly, another weekly and the third once a month.
I set mine up slightly differently, and prefer it.
One folder backs up every second night. As it happens, the first time was an even numbered date.
The second backs up the same files, but starts on an odd numbered date (7th Oct, for illustration) and repeats every 4 days
The third also backs up every 4 days, but starting on the 9th.
This way:-
  1. There's a backup every night
  2. There's never 2 backups on the same night. Given the size of some of my files and the time taken using ethernet over mains, I felt this desirable.
  3. If anything goes wrong with a backup I've got between 3 and 6 days before I have to solve it.
The principle could be extended to 4 or more folders - 3 seemed a good balance between backup drive and doc folder sizes.

PS. Ethernet over mains allows the backup drive to be at the other end of the house, just in case. The house is 200 years old, unaccountably built without ethernet.

Monday, 5 October 2009

Using the subconscious

At school there was one (and only one) maths problem I couldn't solve; I thought it was a distance problem when it was actually a time problem - I was looking at it the wrong way.
It must have laid buried in my subconscious for 7 years - I don't think I ever thought about it, or why I couldn't solve it. Then the answer popped into my head, catching me completely by surprise. It took a minute or so to recall what on earth the original question was!
Jenny Ireland (now Crebbin) and I were chasing a boat which had broken from its moorings; as well as wondering how far down the beach it would come ashore I wondered when. That insight, that a distance problem could equally be a time problem, proved the trigger.
To this day I rely more than most on the subconscious' ability to re-organise disparate snippets into some new and insightful order. I'll often go to sleep with the snippets whirling around, knowing there's a good chance the answer (or at least the key next question) will pop out in the morning.
Difficult decision? Tricky personal issue? Make a 'pretend' decision or draft the response late at night, then go to bed. In the morning the subconscious will tell me if it's right or wrong, and if wrong, where to look next.

I'm neither the first nor the last to do this. Einstein said "The intellect has little to do on the road to discovery. There comes a leap in consciousness, call it intuition or what you will, and the solution comes to you and you don't know how or why."

Thursday, 1 October 2009

Unjustified blind faith in technology

More by luck than anything, I found my automatic backups weren't working. And hadn't worked for 9 months...
Having spent perhaps a grand on backup kit over the years (including 440 quid to recover a crashed hard drive) this hurt. In the hope it helps at least one person to avoid similar problems, here's the tale:-

  • The backup drive (NAS, at the other end of the house, connected by ethernet-over-mains) needs restarting manually after any power cut. I'd forgotten to do this. (We get a lot of power cuts. I read somewhere that the airport takes priority when suppliers are low, and on balance I'd prefer them to keep the runway lights on. Even if I'm not flying!)
  • The backup software didn't tell me. I assume if it can't see the drive (which was still switched off) it assumes I know what I'd doing. And I assumed it would tell me.
  • As far as I can tell the NAS drive got full sometime along the way. On previous occasions I'm sure it warned me, but - perhaps coincidentally ...
    • The backup software broke.
Bit of a fright, and quite a time sponge to sort through all the causes and get back to some sort of stability. Along the way I found Gina Trapani's excellent HowTo at
When it's a new, strange or forgotten area, I need instructions to start from what I don't know, not what the author does. And she did. Written Jan 2006, the page has had over half a million hits. She deserves every one.