tinyramfs/docs/tinyramfs.cmdline.7.scd
2020-09-10 22:53:39 +03:00

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tinyramfs.cmdline(7)
# NAME
Tinyramfs - kernel command-line parameters
# DESCRIPTION
Tinyramfs provides a way to control configuration dynamically via
kernel parameters without needing to regenerate initramfs image.
## MAN PAGE SYNTAX
```
| - OR
... - can be repeated
```
# GENERAL PARAMETERS
*debug*=1
Enable debug mode.
*break*=breakpoint
Specify breakpoint where shell should be invoked. Useful for
debugging. List of builtin breakpoints:
- root
- boot
Hooks can provide their own breakpoints. See source code of hooks
for more information.
*root*=UUID|LABEL|/dev/\*|PARTUUID
Specify which way tinyramfs will use to look up root filesystem.
- UUID - lookup device by uuid
- LABEL - lookup device by label
- /dev/\* - lookup device by full path
- PARTUUID - lookup device by partition uuid
Initramfs must contain *blkid*(8) for ability to use UUID, LABEL,
PARTUUID. Note that PARTUUID only supported in util-linux *blkid*(8).
*root_type*|*rootfstype*=type
Explicitly set root filesystem type. Kernel must support specified type.
*rootdelay*=delay
Specify maximum number of seconds to wait for root device. Default is 30.
*root_opts*|*rootflags*=opts
See *fstab*(5) fourth field.
# HOOKS PARAMETERS
Initramfs must contain appropriate hooks for ability to use below parameters.
## LVM
*lvm_tag*=tag
Specify LVM tag which will be used to trigger LVM. This option will be
ignored if *lvm_name*/*lvm_group* was specified.
*lvm_name*=name
Specify LVM name which will be used to trigger LVM. *lvm_group* must be
specified.
*lvm_group*=group
Specify LVM group which will be used to trigger LVM.
*lvm_discard*=1
Pass issue_discards to lvm. Leave empty to disable. Useful for SSD's.
## LUKS
*luks_name*=name
Specify which name will be registered to mapping table after cryptsetup
unlocks LUKS root.
*luks_root*=UUID|LABEL|/dev/\*|PARTUUID
See *root* for details.
*luks_discard*=1
Pass --allow-discards to *cryptsetup*. Leave empty to disable. Useful for
SSD's, but you must know that security will be decreased.
# EXAMPLES
## ROOT
```
vmlinuz initrd=\initramfs root=/dev/sda1 ...
```
## DISABLE DISCARD
```
vmlinuz initrd=\\initramfs luks_discard= lvm_discard= ...
```
## PASS ARGUMENTS TO REAL INIT
```
vmlinuz initrd=\\initramfs ... -- args
```
# SEE ALSO
*tinyramfs*(8) *tinyramfs.config*(5) *tinyramfs.hooks*(7)