Can one remove a specific file from all snapshots?

[Rick Romero]

  Quoting Rainer Duffner <rainer at ultra-secure.de>:

>> Am 18.05.2018 um 22:17 schrieb Alex Aminoff <aminoff at nber.org>:
>>
>> The use case here is that we have data sets of sensitive data that  
>> we are contractually obligated to delete with no backups at a  
>> certain point in time. The datasets are stored on a ZFS filesystem  
>> (on a truenas from IxSystems as it happens). The snapshots are kept  
>> for 15 days, so at the moment we have to rm the files 15 days  
>> before the deadline to be compliant. Is there a way to delete a  
>> specific file from the live filesystem as well as all the snapshots?
>>
>> I did find a post to this list from 2014:
>>
>> https://lists.freebsd.org/pipermail/freebsd-fs/2014-October/020307.html
>>
>> but I don't think it is relevant, and in any case it does not  
>> appear that the feature that post describes was implemented.
>>
>> Thanks,
>
> AFAIK, snapshots are still read-only.
>
> BTRFS seems to have writable snapshots - but I’ve no idea how it  
> actually works.
>
> I would suggest to change your contracts - that will be much easier  
> than changing ZFS.

Create a dataset and mount it below the current file location, and put  
that file there.  Assuming SMB, it should still be shared out, just  
one folder below.  Then don't include that dataset in the snapshots  
(or do a different rotation).

Rick