Storage preparation for Oracle: multipath, persistent device names, ASM disks

Applied once, before installing Oracle Grid Infrastructure, Oracle Restart or the database: SAN LUNs are identified by WWID, DM-Multipath aliases are configured where needed, and ASM disks get a persistent name and grid:asmadmin ownership through a udev rule or an ASMLib label (if AFD is chosen, prepared so that the installer labels them); if ASM is not used, an LVM + XFS file system and fstab entries are prepared instead. On RAC the same layout is built on all nodes and compared. At the end the disks keep their names and permissions across reboots and are ready for the Grid installation to use directly; to add disks to an existing ASM later, use the ASM day-to-day operations guide.

Topology: 1 server, or 2–8 RAC nodes + SAN/iSCSI/VM disks

Before you start

• The storage team has presented the LUNs… and every LUN is visible on all nodes…; you have a LUN → WWID → usage (DATA/FRA/CRS or mount point) list. The … disks in the form match this list.
• SAN connectivity is in place: for FC the HBAs are connected to the fabric and zoned; for iSCSI the sessions are logged in. Each LUN shows at least 2 paths.
• The disks hold no data (no partition, file system, LVM or old ASM header). On the wrong disk, the partitioning/labeling/mkfs steps in this guide destroy data.
• The server…s… can reach the operating system repositories (…OL7: ol7_latest; RHEL7: ELS subscription…OL: ol…_baseos_latest / ol…_appstream… / ol…_addons…; RHEL: BaseOS + AppStream…) or an internal mirror is configured.
• The ASMLib library …oracleasmlib-3..el….x86_64.rpm…oracleasmlib-2.0..el7.x86_64.rpm… has been downloaded from the oracle.com ASMLib download page and is in …… on every node….
• This guide does not label disks for AFD: the disks are given grid:asmadmin ownership by a udev rule, and the labels are written by gridSetup.sh (oracle.install.asm.configureAFD=true) in the Oracle Restart: Grid Infrastructure + ASM guide. The running kernel is older than 5.14 (RHCK 3.10/4.18 or UEK4–UEK6) and is listed for 19c AFD in MOS 1369107.1.
• A maintenance window is scheduled; a backup/snapshot of the server…s… has been taken and the LUN mapping has been confirmed with the storage team.

Phases of the guide

• Identify the disks — List the disks and their WWIDs · Verify the WWIDs from the form (…every node…server…)
• DM-Multipath — Install and enable device-mapper-multipath · Write /etc/multipath.conf · Load the configuration and verify the paths · Compare the alias–WWID mapping (…)
• ASM user and groups — Prepare the Oracle groups and the grid user
• ASM Filter Driver (AFD) pre-check — Check that the kernel supports AFD
• udev rule (persistent name and permissions) — Write the udev rules file · Apply the rules and verify permissions
• ASMLib (oracleasm) — Install the ASMLib software · Enable io_uring (ASMLib v3) · Configure ASMLib · Create a single partition on the disks… (node 1 only)… · Write the ASMLib labels… (node 1 only)… · Read partitions and labels on the other nodes (…) …
• Verification and next step — Summarize persistent names and permissions · Reboot test