Linux does not restart to recognize newly mounted disks

The RAC database expands the storage space. The newly mounted disk is not recognized and cannot be seen through the fdisk -l command. After querying, you need to restart or scan to see the newly mounted disk. Today I will share the specific method.

I. Overview

The RAC database expands the storage space. The newly mounted disk is not recognized and cannot be seen through the fdisk -l command. After querying, you need to restart or scan to see the newly mounted disk. Today I will share the specific method.

Environment: OEL 6.4 and RAC 11.2.0.4

2. Key matters

Do not use /dev/sdX or /dev/dm-XX as the device name because this device name may change after a reboot
Identify device using WWID
Worldwide identifiers (WWID) can be used to reliably identify disk devices.
A WWID is a persistent, system-independent ID that the SCSI standard requires all SCSI devices to provide.

3. Display all available WWIDs on the system

Shell script to display WWID on your system
#!/bin/bash
#
#Usage:  As root user run : ./check_wwid.sh 
#
for FILE in `find /dev -name "sd*" | sort`
   do
     WWID=`scsi_id --whitelisted --replace-whitespace --device=$FILE `
     echo $FILE " WWID:  "  $WWID
   done

$ sudo ./check_wwid.sh
..
/dev/sdb   WWID:   1ATA_VBOX_HARDDISK_VB81c4f844-94203a15
/dev/sdb1  WWID:   1ATA_VBOX_HARDDISK_VB81c4f844-94203a15
/dev/sdc   WWID:   1ATA_VBOX_HARDDISK_VB2ed83c09-e66dbcfb
/dev/sdc1  WWID:   1ATA_VBOX_HARDDISK_VB2ed83c09-e66dbcfb
..
--> Of course WWIDs for partitions and for the complete disk are identical 

# cat 99-oracle-asmdevices.rules
KERNEL=="sd*", SUBSYSTEM=="block", ENV{DEVTYPE}=="disk", ENV{ID_SERIAL}=="14f504e46494c45523264556151442d5261336d2d566e4250", OWNER="grid", GROUP="asmadmin", MODE="0660"

# ls -ls /dev/sdr
0 brw-rw----. 1 grid asmadmin 65, 16 Mar 19 14:42 /dev/sdr

Reload and Restart the udev rules 
# udevadm control --reload-rules
# start_udev
Starting udev:                                             [  OK  ]
Verify disk protections:
# ls -ltr /dev/asm*
brw-rw----. 1 grid asmadmin   8,  17 Mar 15 10:03 /dev/asmdisk1_udev_sdb1
brw-rw----. 1 grid asmadmin   8,  33 Mar 15 10:03 /dev/asmdisk2_udev_sdc1

Redistribute   99-oracle-asmdevices.rules file to all cluster nodes and restat udev echo system on these nodes
# scp 99-oracle-asmdevices.rules grac42:/etc/udev/rules.d
# scp 99-oracle-asmdevices.rules grac43:/etc/udev/rules.d

On each RAC node
# udevadm control --reload-rules
# start_udev
# ls -ltr /dev/asm*
brw-rw----. 1 grid asmadmin   8,  17 Mar 15 10:03 /dev/asmdisk1_udev_sdb1
brw-rw----. 1 grid asmadmin   8,  33 Mar 15 10:03 /dev/asmdisk2_udev_sdc1

4. UDev rules for disk partitions using /sbin/scsi_id (preferred mode because we can change the name)

Note this example mapping: /dev/sdb1 to /dev/asmdisk1_udev_sdb1:

# cat 99-oracle-asmdevices.rules
KERNEL=="sd?1", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VB81c4f844-94203a15", NAME=
"asmdisk1_udev_sdb1", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd?1", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VB2ed83c09-e66dbcfb", NAME=
"asmdisk1_udev_sdc1", OWNER="grid", GROUP="asmadmin", MODE="0660"

# ls -l /dev/asmdisk1_udev_sdb1 /dev/asmdisk1_udev_sdc1
brw-rw----. 1 grid asmadmin 8, 17 Mar 19 13:53 /dev/asmdisk1_udev_sdb1
brw-rw----. 1 grid asmadmin 8, 33 Mar 19 13:53 /dev/asmdisk1_udev_sdc1

5. Disk group

(1) Expanding disk group

Find path:

select group_number,disk_number ,path from v$asm_disk;

Expanding disk group:

alter diskgroup data2 add disk '/dev/asm-diski';
ALTER DISKGROUP DATA2 REBALANCE POWER 10; 

View is balanced completion:

select operation,est_minutes from v$asm_operation;

Modify it after completion:

alter diskgroup DATA rebalance power 1;

Or: do the balancing directly:

alter diskgroup DATA add disk '/dev/asm-diski' rebalance power 10;

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