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robustness

robustness

From:
Date:
2014-10-14 @ 04:30
Hello,

On the website I read:
   "The main goal of Attic is to provide an efficient and secure way to 
backup data."

But how safe is it?
Can I trust it not to break the repository during power lost, if the 
filesystem survives? 

Re: [attic] robustness

From:
Jonas Borgström
Date:
2014-10-14 @ 19:30
On 2014-10-14 06:30, brankush@hushmail.com wrote:
> Hello,
> 
> On the website I read:
>    "The main goal of Attic is to provide an efficient and secure way to 
backup data."
> 
> But how safe is it?
> Can I trust it not to break the repository during power lost, if the 
filesystem survives? 

The repository is designed to be very robust. All repository operations
(create and delete archive) are atomic. The underlying repository file
IO is strictly append only (no random access).

So as long as the filesystem survives in a consistent state without any
data loss the repository should be fine and any pending partial
transaction will be rolled back.

That said, it's never a good idea to only have one copy of data you care
about. So I would recommend that you use rsync to periodically make an
off-site copy of your repository.
To make sure your good off-site copy is never overwritten by a corrupted
local repository it's a good idea to run "attic check --repository-only"
before the rsync.

/ Jonas

smart prune

From:
Date:
2014-10-14 @ 20:16
Hello,

Shameless is back with another feature request :)

The prune should be based on files. If I have a file (a) changed daily, 
and another one (b) changed monthly, and I have to keep only one arhive 
per month (as a target/objective), I whould not delete the archive which 
holds the b's changes.

So, during a smart-prune, if you have to clean-up one month, you have a 
list of archives and want to keep only one arhive (user's advice, not a 
command, because he doesn't know what is doing), you do this: if some file
is changed only in one arhive, keep that archive. If a different file is 
changed only in another archive from the list, keep that archive too. You 
may end up with more archives in a month, but I say this is what the user 
wants from a smart-prune.

mount / fuse / refresh

From:
Date:
2014-10-14 @ 19:51
I've nothiced that mount is not refreshed (or at least the archives 
created after the attic mount doesn't show up).

I'd like to have a read-only history exported with samba. But, currently I
have to remount it with "fusermount -u ..; attic mount ...". Which is not 
a good ideea, because files can be accessed right at that moment.

So, without shame, a feature request:

It will be nice if the repository (archive list) is read:
   a) from time to time (1-10minutes)
   b) when path doesn't exists (/repository/new-arhive/); a cache for 
'non-existing' will be needed to avoid reading 
/repository/non-existing/pathN too often. 
   c) on some signal (HUP, USR1)

I think (a) is the best. Default 1 min, if the archive list modifications 
can be detected fast, like mtime&stuff, or 3-10 minutes if not.

Thank you for this program.

Re: [attic] robustness

From:
Date:
2014-10-14 @ 19:38
On 10/14/2014 at 10:30 PM, "Jonas Borgström" <jonas@borgstrom.se> wrote:
>That said, it's never a good idea to only have one copy of data 
>you care about. So I would recommend that you use rsync to periodically 
>make an off-site copy of your repository.
>To make sure your good off-site copy is never overwritten by a corrupted
>local repository it's a good idea to run "attic check --repository-only"
>before the rsync.

Yes! Thank you! This is a must.