I’m wondering what backup strategies people are using. Mostly related to backup retention.
I am backing up up four computers - two Linux, two Windows, one of those Windows is remote (but since it’s VPN connected 100% of the time, UrBackup sees it as a local). If have a 4Tb drive hooked up to a Raspberry Pi3 that runs the UrBackup server. The only significant thing on that 4Tb drive is the Pi’s OS (small) and the UrBackup server and data.
My UrBackup settings are (settings are the same for all four client computers):
Incremental file: every 24 hours, min 31, max 366
Full file: every 30 days, min 2, max 12
Incremental image: every 30 days, min 2, max 12 (Windows only)
Full image: every 90 days, min 2, max 5 (Windows only)
Soft filesystem quota: 95%
No archiving
No per-client limits
I just kind of pulled those above settings out of thin air, not really knowing what would be best.
After using the above UrBackup settings for four months, I have consumed just under 1Tb of my 4Tb drive, so right at 25% of the disk. My backup space usage is very linear, you could draw the UrBackup graph line with a straight ruler, except for the small bumps for the image backups. So projection of future space needs is pretty easy. I figure I’ll hit the “max 366 incremental (daily) file backups” limit before I hit the “95% filesystem quota” limit. So I should easily fit “one years worth of daily backups” onto this 4Tb drive.
What would people recommend for settings considering that I plan to just keep UrBackup running and running and running, probably for years? Less frequent backups? Smaller max settings? Start using archiving? Based on my usage and how much I’d be willing to lose in a disaster, I could back off to once-per-week file backups. But I wouldn’t want to go less frequent than that. I am most comfortable with daily backups. And I would prefer around 3 months of available backups (not necessarily daily) to give my family time to recognize that they might have accidentally deleted a file and need to recover it from backup. I’ve got this level of comfort with my current settings, but keeping 366 daily backups for each computer seems a tad excessive and possibly wasteful. What “better” settings would people recommend?
Since UrBackup uses hard links (as opposed to symlinks) to connect unchanged files in backup storage, I would think I could even run an external script to pick and choose individual backups to delete. Possibly keeping one month of dailys, then three months of weeklies, then a couple of years of monthlies. Just target the specific daily backups that I no long need to keep and delete them, the remaining hard links would be unaffected. This may be ill-advised though. Preferably, UrBackup should handle all file “roll ups” IMHO.