Oracle RAC - udev rules for DM multipath (not used)

category: solutionz · date: 2016-12-31 · updated: 2026-10-02 · author: LALA

Oracle RAC Solution · Config document · referenced from Storage and ASM disks

noteThis file was written down as a variant and was not used on these nodes. Its device names do not match the LUNs of this system.

The form the udev rules would take if the shared LUNs were reached through DM multipath: the multipath map already has a stable name, so the rules only set owner, group and mode by that name. The nodes have a single iSCSI interface and no multipath layer; the rules in use are udev rules for the ASM disks.

Item	Value
Path	`/etc/udev/rules.d/12-persistent-disk.rules`
On	no host; a variant kept in the notes
Shown here	the part the notes show; they mark it as an addition to an existing file
Owner, group and mode set by the rules	`grid`, `asmadmin`, 660
Operating system	SUSE Linux Enterprise Server 11 SP3

The file

ini

# ... (the existing file continues above; the notes do not show it)
# Owner (grid) and group (dba) for Oracle on the multipath block devices
ENV{DM_NAME}=="ORADB01-ORA-INSTALL", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-CRS", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-DATA1", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-DATA2", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-DATA3", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-DATA4", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-FRA", OWNER:="grid", GROUP:="asmadmin", MODE:="660"
ENV{DM_NAME}=="ORADB-ONTRLG", OWNER:="grid", GROUP:="asmadmin", MODE:="660"

LABEL="dm_end"

Line	Meaning
`ENV{DM_NAME}=="ORADB-CRS"`	matches the device-mapper device whose map name, the multipath alias, is `ORADB-CRS`
`OWNER:="grid", GROUP:="asmadmin", MODE:="660"`	`:=` is a final assignment: later rules cannot change the value again
`LABEL="dm_end"`	a jump target; a rule earlier in the file, which the notes do not show, would skip to it with `GOTO` for devices that are not device-mapper devices

What does not fit this system, and stays as it is in the notes:

In this file	On the nodes
`ORADB-DATA1` to `ORADB-DATA4`, four data disks	`ORADB-DATA01` and `ORADB-DATA02`, two data disks
`ORADB01-ORA-INSTALL` owned by `grid:asmadmin`	the install disk is `ORADB-INSTALL`, a local LVM physical volume with an ext3 file system, not an ASM disk
the comment says group `dba`	the rules set the group `asmadmin`
no symlinks, no partitions	the rules in use match the first partition and create two symlinks per disk

The differences suggest the block was carried over from another layout. The notes hold no multipath.conf and no alias definitions that would give the maps these names.

Checked against udev in SLES 15 SP7

As built	Today
`OWNER:=`, `GROUP:=`, `MODE:=`	Unchanged: `:=` assigns a value finally and disallows later changes
a rules file for device identification, no further step	SUSE's multipath documentation notes that changed udev rules for device identification need the initrd rebuilt with `dracut -f`

I found no vendor documentation that describes a DM_NAME rule for ASM, so this variant remains what it was in the notes: an untested sketch.