Quote:
Originally Posted by gregbradley
I do keep copies on external HDD but they can be unreliable (especially if you leave them in a car and get a 40C day).
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I think external hard disks have become significantly less reliable in the last few years. They seem to me to be more susceptible to heat and knocks and bad electrical connections (less gold on the USB connection cables ?? )
All my business customers have at least two alternating offsite USB backups in addition to other backups / archiving (e.g. NAS devices & internet-based storage) - and they are replaced every three years maximum. I still believe portable USB disks are an essential part of any backup strategy despite what the online backup vendors might say. Three of my bigger clients have recovered from large scale ransomware attacks thanks to physically disconnected USB disks !
One thing to be aware of with old disk archives is the concept of "bitrot" where data on hard disks gets silently corrupted and you have no idea its happened. That corrupt data can then be propagated to new disks, or to something like dropbox, and unless you are viewing the photo or video you may not know its corrupted.
For this reason I have my main data repository of "everything" on a small windows server and I run a cheap software application called Fastsum on a regular basis. It initially creates checksums of all the data files on the server, one checksum file per folder.
Then at regular intervals I re-run the software, it recalculates the checksums and compares them to the previous values (creating new checksums for added files). This methodology will highlight any corrupted / changed / deleted data files for you to review. if any files are genuinely corrupted you can restore them from other 'known good' backups such as NAS / USB / internet storage.
Some newer operating systems have this checksum capability built in to the operating system but this manual method using Fastsum is sufficient for my business and personal data and client documentation.