11

The corporation I worked at some time ago had an awesome system of snapshots allowing for very easy recovery from any mistakes in case you broke something.

All software development was performed on a network drive, that had a special feature: in every single folder you could enter a hidden subfolder .snapshots and in it were subfolders for 1 hour, 2 hours, 3 hours, 4 hours and every of 7 days of the week prior, each of them containing a complete backup of said directory (including all subdirectories).

I doubt it was performed as actual copies on disk, as that would result in extreme redundancy:

  • /.snapshots/1_hour/devel/lib/project/extras/file.txt
  • /devel/.snapshots/1_hour/lib/project/extras/file.txt
  • /devel/lib/.snapshots/1_hour/project/extras/file.txt
  • /devel/lib/project/.snapshots/1_hour/extras/file.txt
  • /devel/lib/project/extras/.snapshots/1_hour/file.txt

all lead to the same file, and considering the sheer volume of all projects creating physical mirrors of the whole system every hour was unlikely. (the directory names could have been different, it was some time ago and my memory is rather sketchy

I have no clue what OS and hardware that worked on, and what underlying software provided that functionality - that was the wizardry of the network admins, and all us, code monkeys, would see was a samba share with these subdirectories, populating themselves magically if only created, so I can't give much more detail.

Can you tell me what kind of software provides that kind of functionality?

4

This sounds remarkably like rsnapshot

  • It creates hourly, daily and weekly snapshots if set up correctly (You basically create cronjobs)
  • it uses hardlinks to save on space
  • You can use this for both remote or local backups, since it uses rsync

If all this command line stuff seems too difficult, or you want some fancier features dejadup is a gui snapshot program thats a front end for duplicaity. It does incremental encrypted backups, on a schedule, and you can recover from any one of those backups. Its probably not what your sysadmins were using.

Both these options are clever wrappers around rsync, which is also worth checking out if you're rolling your own backup script

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