Detailed example of rsync-incr operation
Posted on :: rsync-incr

Let's say we have a source directory, dir that we are going to backup into backup with default options and backup--snap with --snap. We will have in it the files:

- On Day 1
  - B
  - C
  - D
- On Day 2
  - A is Added
  - B stay the same in Both days
  - C is Changed
  - D is Deleted and not there anymore

So, on Day 1:

We set up the source

# mkdir dir; echo bbb >dir/B;echo ccc >dir/C;echo ddd >dir/D
# ls -l dir
total 12
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 C
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 D

We backup normally

# rsync-incr 5 dir backups/dir
# ls -lR backups
backups:
total 8
drwxrwxr-x 2 colas local 4096 Jan 10 23:40 dir
drwxrwxr-x 2 colas local 4096 Jan 10 23:42 dir.past

backups/dir:
total 12
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 C
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 D

backups/dir.past:
total 4
-rw-rw-r-- 1 colas local 17 Jan 10 23:42 LAST_DATE

We backup with --snap

# rsync-incr --snap 5 dir backups--snap/dir
# ls -lR backups--snap
backups--snap:
total 8
drwxrwxr-x 2 colas local 4096 Jan 10 23:40 dir
drwxrwxr-x 3 colas local 4096 Jan 10 23:44 dir.past

backups--snap/dir:
total 12
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 C
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 D

backups--snap/dir.past:
total 8
drwxrwxr-x 2 colas local 4096 Jan 10 23:44 2009-01-10.23h44-0m
-rw-rw-r-- 1 colas local 17 Jan 10 23:44 LAST_DATE

backups--snap/dir.past/2009-01-10.23h44-0m:
total 0

On day 2

We set up the source

# rm dir/D; echo aaa>dir/A; echo CCC>dir/C
# ls -l dir/
total 12
-rw-rw-r-- 1 colas local 4 Jan 10 23:48 A
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:48 C

We backup normally

# rsync-incr 5 dir backups/dir
# ls -lR backups
backups:
total 8
drwxrwxr-x 2 colas local 4096 Jan 10 23:48 dir
drwxrwxr-x 3 colas local 4096 Jan 10 23:50 dir.past
 backups/dir:
total 12
-rw-rw-r-- 1 colas local 4 Jan 10 23:48 A
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:48 C
 backups/dir.past:
total 8
drwxrwxr-x 2 colas local 4096 Jan 10 23:50 2009-01-10.23h42-1m
-rw-rw-r-- 1 colas local 17 Jan 10 23:50 LAST_DATE
 backups/dir.past/2009-01-10.23h42-1m:
total 8
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 C
-rw-rw-r-- 1 colas local 4 Jan 10 23:40 D

There, you can see that the "past" backup dir contains an image of the whole of dir the "day" before. But you see that B has a link count of 2 so is shared between the 2 backup dirs, whereas C is not, the 2 C files have different contents

We backup with --snap

# rsync-incr --snap 5 dir backups/dir
# ls -lR backups--snap/:
total 8
drwxrwxr-x 2 colas local 4096 Jan 10 23:30 dir
drwxrwxr-x 4 colas local 4096 Jan 10 23:30 dir.past

backups--snap/dir:
total 12
-rw-rw-r-- 1 colas local 4 Jan 10 23:30 A
-rw-rw-r-- 2 colas local 4 Jan 10 23:27 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:30 C

backups--snap/dir.past:
total 12
drwxrwxr-x 2 colas local 4096 Jan 10 23:30 2009-01-10.23h30-0m
drwxrwxr-x 2 colas local 4096 Jan 10 23:27 2009-01-10.23h30-1m
-rw-rw-r-- 1 colas local 17 Jan 10 23:30 LAST_DATE

backups--snap/dir.past/2009-01-10.23h30-0m:
total 0

backups--snap/dir.past/2009-01-10.23h30-1m:
total 12
-rw-rw-r-- 2 colas local 4 Jan 10 23:27 B
-rw-rw-r-- 1 colas local 4 Jan 10 23:27 C
-rw-rw-r-- 1 colas local 4 Jan 10 23:27 D

There, you can see that the "past" backup dir contains an image of the whole of dir the "day" before. But you see that B has a link count of 2 so is shared between the 2 backup dirs, whereas C is not, the 2 C files have different contents

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