48 ?÷o display for a block device. If multiple path names exist for a block device, and LVM needs to display a name for the device, the path names are matched against each item in this list of regular expressions. The first match is used. Try to avoid using undescriptive /dev/dm-N names, if present. If no preferred name matches, or if preferred_names are not defined, the following built-in preferences are applied in order until one produces a preferred name: Prefer names with path prefixes in the order of: /dev/mapper, /dev/disk, /dev/dm-*, /dev/block. Prefer the name with the least number of slashes. Prefer a name that is a symlink. Prefer the path with least value in lexicographical order. # Example preferred_names = [ "^/dev/mpath/", "^/dev/mapper/mpath", "^/dev/[hs]d" ] # Enable or disable the use of a devices file. When enabled, lvm will only use devices that are listed in the devices file. A devices file will be used, regardless of this setting, when the --devicesfile option is set to a specific file name. The name of the system devices file, listing devices that LVM should use. This should not be used to select a non-system devices file. The --devicesfile option is intended for alternative devices files. The max number of backup files to keep in /etc/lvm/devices/backup. LVM creates a backup of the devices file each time a new version is created, or each time a modification is detected. When the max number of backups is reached, the oldest are removed to remain at the limit. Set to 0 to disable backups. Only the system devices file is backed up. Look outside of the devices file for missing devname entries. A devname entry is used for a device that does not have a stable device id, e.g. wwid, so the unstable device name is used as the device id. After reboot, or if the device is reattached, the device name may change, in which case lvm will not find the expected PV on the device listed in the devices file. This setting controls whether lvm will search other devices, outside the devices file, to look for the missing PV on a renamed device. If "none", lvm will not look at other devices, and the PV may appear to be missing. If "auto", lvm will look at other devices, but only those that are likely to have the PV. If "all", lvm will look at all devices on the system. Find PVs on new devices and update the device IDs in the devices file. If PVs are restored or moved to a new system with new devices, but an old system.devices remains with old device IDs, then search for the PVIDs on new devices and update the device IDs in system.devices. The original device IDs must also not be found on the new system. See device_ids_refresh_check for conditions that trigger the refresh. Conditions that trigger device_ids_refresh to locate PVIDs on new devices. product_uuid: refresh if /sys/devices/virtual/dmi/id/product_uuid does not match the value saved in system.devices. hostname: refresh if hostname does not match the value saved in system.devices. (hostname is used if product_uuid is not available.) Remove values from this list to prevent lvm from using them. Limit the block devices that are used by LVM commands. This is a list of regular expressions used to accept or reject block device path names. Each regex is delimited by a vertical bar '|' (or any character) and is preceded by 'a' to accept the path, or by 'r' to reject the path. The first regex in the list to match the path is used, producing the 'a' or 'r' result for the device. When multiple path names exist for a block device, if any path name matches an 'a' pattern before an 'r' pattern, then the device is accepted. If all the path names match an 'r' pattern first, then the device is rejected. Unmatching path names do not affect the accept or reject decision. If no path names for a device match a pattern, then the device is accepted. Be careful mixing 'a' and 'r' patterns, as the combination might produce unexpected results (test changes.) Run vgscan after changing the filter to regenerate the cache. # Example Accept every block