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Re: Question about mitigating large storage costs in case of ransomware
- To: Rob Hoelz <firstname.lastname@example.org>
- Subject: Re: Question about mitigating large storage costs in case of ransomware
- From: Garance AE Drosehn <email@example.com>
- Date: Wed, 12 Jul 2017 16:03:30 -0400
- Cc: firstname.lastname@example.org
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- In-reply-to: <20170712093639.440f9300@pyxis>
- References: <20170712093639.440f9300@pyxis>
Here's a strategy I use, although I wasn't thinking of ransomware at the time.
I have a script which first does a 'tarsnap --dry-run', and parses the summary output from that. It checks the 'Total Size' and 'Compressed Size' of the new data, and will skip making a real-backup if that size seems unreasonable. Think about this for a second: If you are hit by ransomware, then you probably don't want to upload *any* of that encrypted data to tarsnap's servers.
If the update-size seems reasonable, then I go ahead and create a real update. Note that I also break up my backup into multiple separate tarsnap archives. So, for instance, it might be reasonable for my "Documents" backup to have a lot of new data in it, but it would be extremely suspicious if the backup of all my svn repositories had a huge amount of new data.
What I have is even more convoluted than what I've described, and I'm pretty sure that my scripts wouldn't be useful for others. But that's the direction I would consider if I were you.
Garance Alistair Drosehn = email@example.com
Senior Systems Programmer or gad@FreeBSD.org
> On Jul 12, 2017, at 9:36 AM, Rob Hoelz <firstname.lastname@example.org> wrote:
> Hello fellow tarsnap users!
> I just started using tarsnap, and I was wondering if there exists an
> option (or the potential interest in developing an option) to put a cap
> on an archive size. The reason I ask is on the off chance another
> tarsnap user or I gets bitten by ransomware and it encrypts their /home
> directory, I would expect the archive size for an automated backup to
> really balloon in size (seeing as it's kind of hard to deduplicate and
> compress random data!), and it would be nice to avoid burning through
> one's account balance to add insult to injury. Not that I intend on
> getting bitten by ransomware, but you never know!
> The closest thing I could find is the --maxbw option; is there a
> corresponding option for archive size that I'm not seeing on the