Turns out I've been pruning my #BorgBackup archives wrong. There's a second step involved that actually deletes the "removed" data rather than just (presumably) removing the refrences to that data from the index. While I knew about this second step, I assumed that it was like how it works when you delete a file: the data technically remains intact, but gets overwritten by subsequent writes. Apparently I was wrong about this. I've been pruning—but not compacting—my daily backups monthly for years.
Long story short: I just spent an entire day compacting my backups. My backup storage just went from 71% full to 38%.
![Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined. Is there a way of writing the expression<br>\[ \sum_{n=1}^m f(n) \]<br>in a way that omits the term where $n=a$?</p><p>I know it could be written as<br>\[ \left( \sum_{n=1}^m f(n) \right) - f(a) \]<br>but this doesn't work when $f(a)$ is undefined.](https://social.jlamothe.net/photo/13528377976a61653463c9a386467268-1.png)
tom grzybow
in reply to Jonathan Lamothe • • •