1virt-make-fs(1) Virtualization Support virt-make-fs(1)
2
6 virt-make-fs - Make a filesystem from a tar archive or files
7
9 virt-make-fs [--options] input.tar output.img
10 virt-make-fs [--options] input.tar.gz output.img
12 virt-make-fs [--options] directory output.img
14
16 Virt-make-fs is a command line tool for creating a filesystem from a
17 tar archive or some files in a directory. It is similar to tools like
18 mkisofs(1), genisoimage(1) and mksquashfs(1). Unlike those tools, it
19 can create common filesystem types like ext2/3 or NTFS, which can be
20 useful if you want to attach these filesystems to existing virtual
21 machines (eg. to import large amounts of read-only data to a VM).
22 To create blank disks, use virt-format(1). To create complex layouts,
24 use guestfish(1).
25 Basic usage is:
27 virt-make-fs input output.img
29 where "input" is either a directory containing files that you want to
31 add, or a tar archive (either uncompressed tar or gzip-compressed tar);
32 and output.img is a disk image. The input type is detected
33 automatically. The output disk image defaults to a raw ext2 sparse
34 image unless you specify extra flags (see "OPTIONS" below).
35 FILESYSTEM TYPE
37 The default filesystem type is "ext2". Just about any filesystem type
38 that libguestfs supports can be used (but not read-only formats like
39 ISO9660). Here are some of the more common choices:
40 ext3
42 Note that ext3 filesystems contain a journal, typically 1-32 MB in
43 size. If you are not going to use the filesystem in a way that
44 requires the journal, then this is just wasted overhead.
45 ntfs or vfat
47 Useful if exporting data to a Windows guest.
48 minix
50 Lower overhead than "ext2", but certain limitations on filename
51 length and total filesystem size.
52 EXAMPLE
54 virt-make-fs --type=minix input minixfs.img
56 TO PARTITION OR NOT TO PARTITION
58 Optionally virt-make-fs can add a partition table to the output disk.
59 Adding a partition can make the disk image more compatible with certain
61 virtualized operating systems which don't expect to see a filesystem
62 directly located on a block device (Linux doesn't care and will happily
63 handle both types).
64 On the other hand, if you have a partition table then the output image
66 is no longer a straight filesystem. For example you cannot run fsck(8)
67 directly on a partitioned disk image. (However libguestfs tools such
68 as guestfish(1) and virt-resize(1) can still be used).
69 EXAMPLE
71 Add an MBR partition:
73 virt-make-fs --partition -- input disk.img
75 If the output disk image could be terabyte-sized or larger, it's better
77 to use an EFI/GPT-compatible partition table:
78 virt-make-fs --partition=gpt --size=+4T --format=qcow2 input disk.img
80 EXTRA SPACE
82 Unlike formats such as tar and squashfs, a filesystem does not "just
83 fit" the files that it contains, but might have extra space. Depending
84 on how you are going to use the output, you might think this extra
85 space is wasted and want to minimize it, or you might want to leave
86 space so that more files can be added later. Virt-make-fs defaults to
87 minimizing the extra space, but you can use the --size flag to leave
88 space in the filesystem if you want it.
89 An alternative way to leave extra space but not make the output image
91 any bigger is to use an alternative disk image format (instead of the
92 default "raw" format). Using --format=qcow2 will use the native
93 qemu/KVM qcow2 image format (check your hypervisor supports this before
94 using it). This allows you to choose a large --size but the extra
95 space won't actually be allocated in the image until you try to store
96 something in it.
97 Don’t forget that you can also use local commands including
99 resize2fs(8) and virt-resize(1) to resize existing filesystems, or
100 rerun virt-make-fs to build another image from scratch.
101 EXAMPLE
103 virt-make-fs --format=qcow2 --size=+200M input output.img
105
107 --help
108 Display brief help.
109 --blocksize=512
111 --blocksize=4096
112 This parameter sets the sector size of the output disk image.
113 The default is 512 bytes.
115 See also "guestfs_add_drive_opts" in guestfs(3).
117 --floppy
119 Create a virtual floppy disk.
120 Currently this preselects the size (1440K), partition type (MBR)
122 and filesystem type (VFAT). In future it may also choose the
123 geometry.
124 --size=N
126 --size=+N
127 -s N
128 -s +N
129 Use the --size (or -s) option to choose the size of the output
130 image.
131 If this option is not given, then the output image will be just
133 large enough to contain all the files, with not much wasted space.
134 To choose a fixed size output disk, specify an absolute number
136 followed by b/K/M/G/T/P/E to mean bytes, Kilobytes, Megabytes,
137 Gigabytes, Terabytes, Petabytes or Exabytes. This must be large
138 enough to contain all the input files, else you will get an error.
139 To leave extra space, specify "+" (plus sign) and a number followed
141 by b/K/M/G/T/P/E to mean bytes, Kilobytes, Megabytes, Gigabytes,
142 Terabytes, Petabytes or Exabytes. For example: --size=+200M means
143 enough space for the input files, and (approximately) an extra 200
144 MB free space.
145 Note that virt-make-fs estimates free space, and therefore will not
147 produce filesystems containing precisely the free space requested.
148 (It is much more expensive and time-consuming to produce a
149 filesystem which has precisely the desired free space).
150 --format=FMT
152 -F FMT
153 Choose the output disk image format.
154 The default is "raw" (raw sparse disk image).
156 --type=FS
158 -t FS
159 Choose the output filesystem type.
160 The default is "ext2".
162 Any filesystem which is supported read-write by libguestfs can be
164 used here.
165 --label=LABEL
167 Set the filesystem label.
168 --partition
170 --partition=PARTTYPE
171 If specified, this flag adds an MBR partition table to the output
172 disk image.
173 You can change the partition table type, eg. --partition=gpt for
175 large disks.
176 For MBR, virt-make-fs sets the partition type byte automatically.
178 -v
180 --verbose
181 Enable debugging information.
182 -V
184 --version
185 Display version number and exit.
186 -x Enable libguestfs trace.
188
190 guestfish(1), virt-format(1), virt-resize(1), virt-tar-in(1),
191 mkisofs(1), genisoimage(1), mksquashfs(1), mke2fs(8), resize2fs(8),
192 guestfs(3), http://libguestfs.org/.
193
195 Richard W.M. Jones http://people.redhat.com/~rjones/
196
198 Copyright (C) 2010-2023 Red Hat Inc.
199
201 This program is free software; you can redistribute it and/or modify it
202 under the terms of the GNU General Public License as published by the
203 Free Software Foundation; either version 2 of the License, or (at your
204 option) any later version.
205 This program is distributed in the hope that it will be useful, but
207 WITHOUT ANY WARRANTY; without even the implied warranty of
208 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
209 General Public License for more details.
210 You should have received a copy of the GNU General Public License along
212 with this program; if not, write to the Free Software Foundation, Inc.,
213 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
214
216 To get a list of bugs against libguestfs, use this link:
217 https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
218 To report a new bug against libguestfs, use this link:
220 https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
221 When reporting a bug, please supply:
223 • The version of libguestfs.
225 • Where you got libguestfs (eg. which Linux distro, compiled from
227 source, etc)
228 • Describe the bug accurately and give a way to reproduce it.
230 • Run libguestfs-test-tool(1) and paste the complete, unedited output
232 into the bug report.
233guestfs-tools-1.50.1 2023-04-06 virt-make-fs(1)