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37 .Nd initial ramdisk image as early userland
41 is a small initial ramdisk image that packs a minimal
45 scripts, and many other statically linked tools, such as various
51 as well as some networking tools.
54 is a nice early userland and is required to help mount the root
55 partition residing on an encrypted device or LVM.
57 The statically linked tools are known as the
61 The inclusion of such rescue tools makes
63 can provide with a powerful rescue environment to fix severe problems,
64 e.g., the root partition cannot be mounted.
65 Users can also choose to boot into the rescue mode from the bootloader
72 image formatted with the
79 framework, and is compressed and installed at
80 .Pa /boot/kernel/initrd.img.gz .
81 The following configurations should be added to
86 .Bd -literal -offset indent
88 initrd.img_type="md_image"
89 vfs.root.mountfrom="ufs:md0s0"
94 kernel environment variable can be configured to specify how to
95 mount the real root partition.
96 Its general syntax is:
97 .Bd -literal -offset indent
98 vfs.root.realroot="<type>:[arg1[:arg2[:...]]]"
101 Currently, the supported types of real root partition are:
108 type allows to mount any local filesystem that does not require any
109 special setup apart from the initial discovery and calling the
112 The general format is as follows:
113 .Bd -literal -offset indent
114 vfs.root.realroot="local:<FS-TYPE>:<DEVICE-PATH>[:<OPTIONS>]"
121 types allow to mount volumes supported by
126 The device will be set up after asking the user for the key,
127 and this volume will then be mounted as the root.
128 The general formats are as follows:
129 .Bd -literal -offset indent
130 vfs.root.realroot="crypt:<FS-TYPE>:<DEVICE-PATH>:<MAPPING-NAME>[:<OPTIONS>]"
132 vfs.root.realroot="tcplay:<FS-TYPE>:<DEVICE-PATH>:<MAPPING-NAME>[:<OPTIONS>]"
135 .Bl -tag -width "/boot/kernel/initrd.img.gz"
136 .It Pa /boot/kernel/initrd.img.gz
137 Location of the compressed
142 .Bd -literal -offset indent
143 vfs.root.realroot="local:ufs:/dev/vg00/lv0[:OPTIONS]"
145 vfs.root.realroot="crypt:ufs:/dev/ad0s0a:secvolume[:OPTIONS]"
147 vfs.root.realroot="crypt:hammer2:/dev/serno/XXXXXX.s1d:root[:OPTIONS]"
159 manual page first appeared in
164 manual page was written by
165 .An Aaron LI Aq Mt aly@aaronly.me .
169 image occupies about 10-15 MB wired memory and cannot be freed after
170 chrooting to the real root partition.