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Storage Foundation 7.4.1 Administrator's Guide - Linux

Last Published: 2019-09-25

Product(s): InfoScale & Storage Foundation (7.4.1)

Platform: Linux

Veritas Volume Manager co-existence with Oracle Automatic Storage Management disks

Automatic Storage Management (ASM) disks are the disks used by Oracle Automatic Storage Management software. Veritas Volume Manager (VxVM) co-exists with Oracle ASM disks, by recognizing the disks as the type Oracle ASM. VxVM protects ASM disks from any operations that may overwrite the disk. VxVM classifies and displays the ASM disks as ASM format disks. You cannot initialize an ASM disk, or perform any VxVM operations that may overwrite the disk.

If the disk is claimed as an ASM disk, disk initialization commands fail with an appropriate failure message. The vxdisk init command and the vxdisksetup command fail, even if the force option is specified. The vxprivutil command also fails for disks under ASM control, to prevent any on-disk modification of the ASM device.

If the target disk is under ASM control, any rootability operations that overwrite the target disk fail. A message indicates that the disk is already in use as an ASM disk. The rootability operations include operations to create a VM root image (vxcp_lvmroot command) , create a VM root mirror (vxrootmir command), or restore the LVM root image (vxres_lvmroot command). The vxdestroy_lvmroot command also fails for ASM disks, since the target disk is not under LVM control as expected.

Disks that ASM accessed previously but that no longer belong to an ASM disk group are called FORMER ASM disks. If you remove an ASM disk from ASM control, VxVM labels the disk as a FORMER ASM disk. VxVM enforces the same restrictions for FORMER ASM disks as for ASM disks, to enable ASM to reuse the disk in the future. To use a FORMER ASM disk with VxVM, you must clean the disk of ASM information after you remove the disk from ASM control. If a disk initialization command is issued on a FORMER ASM disk, the command fails. A message indicates that the disk must be cleaned up before the disk can be initialized for use with VxVM.

To remove a FORMER ASM disk from ASM control for use with VxVM

Clean the disk with the dd command to remove all ASM identification information on it. For example:
```
dd if=/dev/zero of=/dev/rdsk/<wholedisk|partition> count=1 bs=1024
```
where wholedisk is a disk name in the format: cxtydz
where partition is a partition name in the format:cxtydzsn
Perform a disk scan:
```
# vxdisk scandisks
```

To view the ASM disks

You can use either of the following commands to display ASM disks:

The vxdisk list command displays the disk type as ASM.

# vxdisk list
DEVICE       TYPE            DISK         GROUP        STATUS 
Disk_0s2     auto:LVM        -            -            LVM 
Disk_1       auto:ASM        -            -            ASM 
EVA4K6K0_0   auto            -            -            online 
EVA4K6K0_1   auto            -            -            online

You

To check if a particular disk is under ASM control

Use the vxmediadisc utility to check if a particular disk is under ASM control.

# /etc/vx/diag.d/vxmediadisc 3pardata0_2798
 3pardata0_2799   ACTIVE

Alternatively, use the utility to check if the disk is under control of any foreign software like LVM or ASM:

# /etc/vx/bin/vxisforeign 3pardata0_2799
 3pardata0_2799   ASM    ACTIVE

# /etc/vx/bin/vxisforeign 3pardata0_2798
 3pardata0_2798   ASM    FORMER