Re: [PLUG] Backups vs Copies: was Avoid Arvixe at all costs!

["Lee H. Marzke" <lee@marzke.net>]

And to be complete,  you essentially get much the same results with  ZFS snapshots
and replication.

The ZFS snapshots show up on the share as a time-stamped  .zfs/xxx directory at
the top level.   This is a full tree, but not using storage space above the delta.
This is all tracked by recording birth times in each block in the merkel tree, and
zfs snapshots just keep old trees around in addition to the current tree / subtree.

You need a script such as zrep on top of ZFS to manage the create/destroy of
these periodic snaps, or that feature is built into the GUI of FreeNAS, Nexenta etc.

The ZFS send replication does the same on the far end.  Some scripts allow you to
keep more or fewer snaps on the destination than the source.

Lee

----- Original Message -----
> From: "Rich Freeman" <r-plug@thefreemanclan.net>
> To: "Philadelphia Linux User's Group Discussion List" <plug@lists.phillylinux.org>
> Sent: Monday, March 27, 2017 11:25:27 AM
> Subject: Re: [PLUG] Backups vs Copies: was Avoid Arvixe at all costs!

> On Mon, Mar 27, 2017 at 11:07 AM, Fred Stluka <fred@bristle.com> wrote:
>> Rich,
>>
>> I get a full backup, plus daily incrementals out of a single rsync
>> command:
>> % rsync -rpogtlv --del --backup --backup-dir=sparse src/ full
>>
>> This updates my full backup tree, but instead of overwriting or
>> deleting files from that tree, it moves them to a new timestamped
>> incremental tree that is sparsely populated only with the files
>> that would have been changed or deleted.
>>
> 
> That essentially works, but you might seriously consider using
> rsnapshot instead in such a situation.  The only thing that changes is
> how the files are organized.
> 
> Instead of a bazillion timestamped files all over the place, you
> instead end up with timestamped parent directories that are populated
> with full backups, which are sparse in the sense that they're full of
> hard-links where files didn't change.
> 
> The advantage of rsnapshot is that you can just copy/rsync one of
> those directories back and you get your filesystem in the state as of
> the timestamp you used (presumably the latest), vs getting a
> filesystem full of timestamped incremental files all over the place
> that you then need to try to clean up.  Either way you can still go
> back in time for any particular file.
> 
> But, they both get the job done, and depending on how you prefer the
> format of your archive and the state after restoration, either could
> be the "better" solution.
> 
> --
> Rich
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-- 
"Between subtle shading and the absence of light lies the nuance of iqlusion..." - Kryptos 

Lee Marzke, lee@marzke.net http://marzke.net/lee/ 
IT Consultant, VMware, VCenter, SAN storage, infrastructure, SW CM 
+1 800-393-5217 office +1 484-348-2230 fax 
+1 252 627-9531 sms ( 252 MARZKE1 )
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