Backup your backup

hard driveHaving managed a network, backup of data is not something I have to think about very much. You just do it, end of story.

On a corporate network it’s easy, and automated software will do the job. All you have to do is remember to change the tapes in the right order, and it will even tell you which tape to use. If you’re big enough, you can even have that automated as well.

Personal backup needs a bit more discipline, and the dangers are more likely to arise from an actual attack on your PC/disc by something deliberately malicious, or more likely, finger trouble on YOUR part leading to deletion or overwriting of an important file or directory. Failure of a hard drive is fairly unlikely, I’ve only seen one genuine case while handling dozens of PCs in a corporate system. I also recall one chap visit me for something else causing his laptop a problem. When he went to show me his problem, I was amused to see him thump the laptop whenever he opened a file – apparently he was so used to doing this he didn’t notice. The drive wouldn’t spin up when accessed (I dismantled and refitted the casing which was twisted, and jamming the drive spindle). The only other case of drive failure was a server, which we were obliged to run 24/7. This held a database that everyone used all during the working day, and we couldn’t run any routines to move its position on the hard drive. After about two years, the network software reported data errors – just a few a day, but every day – when we investigated, sure enough, it was the main database. Our guess was that the disk surface was beginning to break up and fragment, with pieces of the coating becoming detached. Even though this carried on, the server software was able to cope, moving copies of suspect data to ‘safe’ areas of the drive, and this carried on for over a year (when we could afford a new server) without any actual corruption of the data being detected by the users.

I use an ancient PDA, tiny and weak by modern standards, BUT, it does what I need, and stores critical data remote from my main PCs (or is encrypted where it is copied to them). One reason I like it the fact that it has a clip in module that allows memory cards to be used with it, and the module has automated backup firmware built in, so the card backs up the PDA content with no intervention needed once scheduled. This has run fine for years, until last week.

The backup uses the most battery power (it uses cheap NiMh AAA batteries, not LiIon that cost more than the PDA to replace), and if I’m not about to watch the power level, can kill the PDA if it flattens them. Not normally a problem, the PDA operating system is stored in ROM, and contents are backed up to the memory card. Fit freshly charged AAAs, reboot the PDA, restore the backup, and off we go.

Well…not this time.

When the batteries died, the took the memory card with them, and it was as dead as the proverbial dodo, and unreadable too, being unrecognised by any car reader I own. A quick flit around the web showed that all the ‘Card Data Recovery’ programmes only worked for image files, and any decent ones want money – no shareware (unless to prove they could recover the data, but won’t unless unlocked after you pay for them). I did recover some pics I’d transferred to the card, but the data just didn’t appear in any of these so-called data recovery programmes.

Then I remembered one of my card readers had been supplied with a CD-ROM claiming to have loads of useful software on board for free. With nothing to ‘lose’ I thought it was worth a try. The downside was that everything was in German, with no other language options, so I was flying blind. I took a ‘best guess’ at the options, and let it go to work on the card – unlike the other recovery programmes, it appeared to work on the card itself, rather than recover data and copy it to another location, leaving the card unaltered. When it was done, the card appeared to have a number of files restored, so it was out of the reader and into the PDA. Remarkably, even though I hadn’t been able to follow what it had done, the free software had indeed restores SOME of the data. Oddly, it had not restored any of the image files that the others had found (and there were around 1,000 images on the card), but had caught the data that they couldn’t see.

Once I’d had a chance to look closer, I saw that the recovered data was from last October – not really a problem, as the info changes very slowly on the PDA, and most of the important stuff is archive material anyway – so very little went adrift.

Ironically, I had started to use it more frequently in recent weeks, and had planned to install its manager software on my laptop as a result, but hadn’t got round to it. If I had, then it would have been mirrored on the laptop, and even the loss of the backup would have been a non-event. Well,it’s done now. I also knocked the automated backup schedule from daily to weekly, and alternate cards (I’ve got plenty) each week, so even if does blitz one if the batteries die, I’ll only be one backup behind.

Live and learn – even when things are being done ‘right’, you can probably still do them ‘better’.

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