-
Notifications
You must be signed in to change notification settings - Fork 5
/
bigsync.1
91 lines (91 loc) · 3 KB
/
bigsync.1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
.TH BIGSYNC "1" "November 2020" "bigsync 0.4.1" "User Commands"
.SH NAME
bigsync \- backup large files to a slow media
.SH SYNOPSIS
.B bigsync
[\fIOPTION\fR]...
.SH DESCRIPTION
.B Bigsync
will read the source file in chunks calculating checksums for each one.
It will compare them with previously stored values for the destination file and
overwrite changed chunks in it if checksums differ.
.P
This is useful for backing up big files (think disk images) over a network link
to a remote location.
.B bigsync
will read source file thoroughly but will write only the changed chunks to a destination file.
This is very efficient.
.SH OPTIONS
.PP
.TP
\fB\-s\fR <path>, \fB\-\-source\fR <path>
source file name to be back up. Mandatory option.
.TP
\fB\-d\fR <path>, \fB\-\-dest\fR <path>
destination file name or directory.
If directory specified, then file will
have the same name in that directory.
Mandatory option.
.TP
\fB\-b\fR <MB>, \fB\-\-blocksize\fR <MB>
block size in MB. Defaults to 15.
.TP
\fB\-S\fR, \fB\-\-sparse\fR
make output file sparse. That means that all blocks of the original file that consists solely
of zeroes will be stored outside of filesystem. This is a safe option for almost any circumstances
and it is useful for backup of virtual machines, raw devices, etc. Note that not all file systems
support sparse files. It is still safe to use it if so.
.TP
\fB\-r\fR, \fB\-\-rebuild\fR
do not write destination file, only verify/rebuild the checksums file.
.TP
\fB\-t\fR, \fB\-\-notruncate\fR
do not truncate the destinatation file.
.TP
\fB\-c\fR <path>, \fB\-\-checksum\fR <path>
file name to use as checksum file
(defaults to destination file suffixed with .bigsync).
.TP
\fB\-q\fR, \fB\-\-quiet\fR
silence is gold.
.TP
\fB\-v\fR, \fB\-\-verbose\fR
display the checksum of each block and it's status.
.TP
\fB\-h\fR, \fB\-\-help\fR
display this help and exit
.TP
\fB\-V\fR, \fB\-\-version\fR
output version information and exit
.SH BIGSYNC vs RSYNC
rsync does kind of the same thing, too. But rsync does read both files to calculate checksums, which
slows down the whole process a lot when working with slow media. bigsync only reads source file, and
writes only changed blocks to destination, which minimizes load and access to the destination drive.
.SH EXAMPLES
Backup
.B Documents.dmg
into
.B documents.dmb.backup
using block size of 15 megabytes:
.PP
bigsync --source /home/egor/Documents.dmg --dest /media/backup/documents.dmg.backup
.PP
Backup operating system disk image to a folder with backups:
.PP
bigsync --source /home/egor/WinSucks.vdi --dest /media/backup/virtualmachines/
.PP
Backup raw device into a file:
.PP
bigsync --source /dev/hda1 --dest /media/backup/devices/hda1.backup
.PP
Backup raw device to raw device (block device):
.PP
bigsync --source /dev/hda1 --dest /dev/nbd0 --sparse --notruncate --checksum /tmp/checksum
.SH AUTHOR
Written by Egor Egorov.
.SH "REPORTING BUGS"
Report bugs to <[email protected]> or at https://github.com/egorFiNE/bigsync/issues/
.SH COPYRIGHT
Copyright \(co 2009-2020 Egor Egorov
.PP
License: MIT.