Gentoo Archives: gentoo-user

From: Mick <michaelkintzios@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Backup questions
Date: Thu, 09 Aug 2018 15:04:14
Message-Id: 6343740.RVXyl9XVAd@dell_xps
In Reply to: Re: [gentoo-user] Backup questions by Bill Kenworthy
1 On Thursday, 9 August 2018 09:18:43 BST Bill Kenworthy wrote:
2 > On 08/08/18 11:43, Dale wrote:
3 > > Howdy,
4 > >
5 > > Long story short that leads up to my questions, I paid off some debt.
6 >
7 > Hi Dale,
8 >
9 > what you are talking about is not a real backup but a single copy of
10 > your data that may or may not be complete (the delete option you
11 > mention) at a single point in time - not quite as useful as a proper
12 > versioned backup. Whatever your choice, also look at the restore
13 > procedure - very important.
14
15 Well, a static mirror is a full backup at that point in time. If the backed
16 up data changes little over time, it is a valid backup, which can prove its
17 worth if/when the original drive dies, or files are deleted accidentally on
18 the original.
19
20 On the points Dale raised:
21
22 The --delete option will remove from the destination any files which no longer
23 exist on the source. So if you delete photo-1 on the source and then run
24 rsync, photo-1 *will* be deleted from the full back up, to mirror what is
25 currently available on the source directory.
26
27 Here is where incremental/differential backup strategies can be of use, in
28 case some time in the relatively near future you change your mind and wish you
29 never had deleted that old photo-1. The same may apply to user config files,
30 if you stop using an application, manually clean/delete its config files from
31 your home and rsync --delete thereafter. If in the near future you review
32 your position and decide you wanted that application after all and the 2 weeks
33 you had spent configuring it would be of use again, with the --delete option
34 your config files will be gone from the backup. So, use --delete judiciously.
35
36 rsync can on its own provide you with incremental and differential backups,
37 using hard links to the full backup directory, so as to avoid duplication and
38 minimise storage space usage. This means that incremental backups take only a
39 fraction of the space and additional disks or enclosures may be redundant.
40 Take a look at the --backup, --backup-dir, and --link-dest, options.
41
42 As others have posted there are a number of applications which use rsync as a
43 back end and have scripted with config files its options. There's also quite
44 a number of bash scripts on the interwebs offering a starting point if you
45 prefer to hack your own.
46
47 With regards to heat and humidity I suggest you take a look at the
48 manufacturer's specifications, both for the enclosure and for the drives.
49 Invariably environmental thresholds are printed on labels on the devices
50 themselves, or you could google using the part numbers off them.
51
52 HTH.
53 --
54 Regards,
55 Mick

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Subject Author
Re: [gentoo-user] Backup questions Dale <rdalek1967@×××××.com>