6.5.4 Checking Physical Disk Information and Slice Numbers

If system disks have been registered with the root class, check the following details using this procedure and make a note of them.

System volume physical disk information
System volume slice numbers

These details are required for performing system disk backup, restore, and recovery from failure.

Note

When Using the System Volume Snapshot Function

Check also the following details.

Physical disk information on the proxy volumes of system volumes

1) Check the root class name and the system volume names.

# mount
/dev/sfdsk/gdssys2 on / ...
/dev/sfdsk/gdssys4 on /var type ...
/dev/sfdsk/gdssys3 on /usr type ...
/dev/sfdsk/gdssys5 on /boot type ...
/dev/sfdsk/gdssys6 on /boot/efi type ...
...
# swapon -s
Filename                                Type            ...
/dev/sfdsk/gdssys32                     partition       ...

# ls -l /dev/sfdsk/gdssys*
brw-rw---- 1 root disk 231,  2  Jan  5 18:40 /dev/sfdsk/gdssys2
brw-rw---- 1 root disk 231,  3  Jan  5 18:40 /dev/sfdsk/gdssys3
brw-rw---- 1 root disk 231, 32  Jan  5 18:40 /dev/sfdsk/gdssys32
brw-rw---- 1 root disk 231,  4  Jan  5 18:40 /dev/sfdsk/gdssys4
brw-rw---- 1 root disk 231,  5  Jan  5 18:40 /dev/sfdsk/gdssys5
brw-rw---- 1 root disk 231,  6  Jan  5 18:40 /dev/sfdsk/gdssys6
                                                            (*1)

# ls -l /dev/sfdsk/*/dsk/*
brw-r--r-- 1 root root 231,  5  Jan  5 18:41 /dev/sfdsk/System/dsk/bootVolume
brw-r--r-- 1 root root 231,  6  Jan  5 18:41 /dev/sfdsk/System/dsk/efiVolume
brw-r--r-- 1 root root 231,  2  Jan  5 18:41 /dev/sfdsk/System/dsk/rootVolume
brw-r--r-- 1 root root 231, 32  Jan  5 18:41 /dev/sfdsk/System/dsk/swapVolume
brw-r--r-- 1 root root 231,  3  Jan  5 18:41 /dev/sfdsk/System/dsk/usrVolume
brw-r--r-- 1 root root 231,  4  Jan  5 18:41 /dev/sfdsk/System/dsk/varVolume

(*1) In RHEL8.6 or later, the path for the GDS logical volume is /dev/sfdsksysX (X indicates digits).

Find the appropriate device with the same major number and the same minor number. The major or minor number is displayed in each device.

For example, in the case of /dev/sfdsk/gdssys2, the major number is 231 and the minor number is 2. Therefore, /dev/sfdsk/RootClass/dsk/rootVolume is the appropriate device.

Based on this correspondence, match the use and the volume of devices.

In this example, the root class name is System, and the system volume names are as follows:

Use	Volume name
/	rootVolume
/var	varVolume
/usr	usrVolume
/boot	bootVolume
/boot/efi	efiVolume
Swap area	swapVolume

2) Check the group names and slice numbers of the system volumes.

# sdxinfo -V -c System -e long
OBJ    NAME        TYPE   CLASS  GROUP  ... SNUM PJRM
------ ----------  ------ ------ ------ ... ---- ----
volume rootVolume  mirror System Group1 ...    1 *
volume varVolume   mirror System Group1 ...    2 *
volume usrVolume   mirror System Group1 ...    3 *
volume bootVolume  mirror System Group1 ...    4 *
volume efiVolume   mirror System Group1 ...    5 *
volume swapVolume  mirror System Group1 ...    6 *
...

For the -c option, specify the root class name confirmed in step 1).

The group names are displayed in the GROUP fields. In this example, the group name is Group1.

The slice numbers are displayed in the SNUM fields. In this example, the slice numbers are as follows.

Use	Volume name	Slice number
/	rootVolume	1
/var	varVolume	2
/usr	usrVolume	3
/boot	bootVolume	4
/boot/efi	efiVolume	5
Swap area	swapVolume	6

Note

When Using the System Volume Snapshot Function

If the sdxinfo command is executed as above, information on the proxy volumes of the system volumes is given additionally. Check also the group name of the proxy volumes. If the proxy is joined through group operation, the proxy volume slice numbers are the same as those of the corresponding system volume slice numbers.

3) Check the SDX disk names of disks composing the system volumes.

# sdxinfo -G -c System
OBJ   NAME    CLASS    DISKS            ...
----- ------- -------  ---------------- ...
group Group1  System   Root1:Root2      ...

For the -c option, specify the root class name confirmed in step 1).

Check the DISKS field in the line showing the group name confirmed in step 2) in its NAME field.

In this example, the SDX disk names are Root1 and Root2.

Note

When Using the System Volume Snapshot Function

If the sdxinfo command is executed as above, proxy volume group information is given additionally. Check also the SDX disk names of disks composing the proxy volume group.

4) Check the physical disk names of disks composing the system volumes.

# sdxinfo -D -c System
OBJ   NAME    TYPE   CLASS   GROUP   DEVNAM  ...
----  ------  ------ ------  ------  ------  ...
disk  Root1   mirror System  Group1  sda     ...
disk  Root2   mirror System  Group1  sdb     ...

For the -c option, specify the root class name confirmed in step 1).

The physical disk names are displayed in the DEVNAM fields.

In this example, the physical disk names are as follows.

SDX disk name	Physical disk name
Root1	sda
Root2	sdb

Note

When Using the System Volume Snapshot Function

If the sdxinfo command is executed as above, information on disks composing the proxy volumes is given additionally. Check also the physical disk names of those disks.

5) Check information on the physical disks composing the system volumes.

# readlink -f /sys/block/sda/device
/sys/devices/pci0000:02/0000:02:1f.0/0000:06:02.0/host0/target0:0:0/0:0:0:0
# readlink -f /sys/block/sdb/device
/sys/devices/pci0000:02/0000:02:1f.0/0000:06:02.0/host0/target0:0:2/0:0:2:0

For the readlink command arguments, specify /sys/block/physical_disk_name/device.

Among symbolic link destination paths displayed, elements before hostX and the last X:Y:Z is physical disk information.

In this example, it is as follows.

SDX disk name	Physical disk name	Physical disk information
Root1	sda	0000:06:02.0	0:0:0
Root2	sdb	0000:06:02.0	0:2:0

Note

When Using the System Volume Snapshot Function

Using a similar method, check also physical disk information on the proxy volumes of the system volumes.