[Discuss] Cloud-backup solutions for Linux?

Edward Ned Harvey (blu) blu at nedharvey.com
Tue Sep 29 10:34:17 EDT 2015


> From: Discuss [mailto:discuss-bounces+blu=nedharvey.com at blu.org] On
> Behalf Of John Abreau
> 
> When I backup Postgresql databases, I use pg_dumpall to dump the data into
> a text file; I don't try to backup the binary database files.
> 
> I'm not familiar with MongoDB, but I would be surprised if it didn't have a
> similar option to dump its data to a text file.

Databases, indeed, cannot be backed up by naively copying the database file while the daemon is alive. The daemons are, however, smart enough to leave the file(s) in a consistent state (or use something akin to journaling) so the daemon is able to recover after an interruption. I am confident saying that literally every database has these characteristics - even Mongo and Sqlite. I have specifically verified this is correct with Sqlite.

As for the filesystem being in an "inconsistent" state after interruption - That's what journaling is for. If you were in the middle of a "rm" or "mv" operation or something like that, journaling remembers it and correctly handles it after system restore - either by completing the operation or by backing it out as if it never happened. Automatically.



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