LVM volume groups import fails and diskinfo command shows "device busy" error

Article: 100014895
Last Published: 2015-02-15
Ratings: 0 0
Product(s): InfoScale & Storage Foundation

Problem

 LVM volume groups cannot be imported and OS command diskinfo is showing the "device busy" error with dmp_cache_open tunable set to on.

Error Message

# /usr/sbin/vgimport -m /vg-maps/vgcstora1.map -N -v -s /dev/vgcstora1
Beginning the import process on Volume Group "/dev/vgcstora1".
Couldn't access the list of physical volumes for volume group "/dev/vgcstora1".


# diskinfo /dev/rdisk/disk52
diskinfo: can't open /dev/rdisk/disk52: Device busy

# scsimgr lun_map -D /dev/rdisk/disk52

        LUN PATH INFORMATION FOR LUN : /dev/rdisk/disk52

Total number of LUN paths     = 1
World Wide Identifier(WWID)   =

LUN path : lunpath16
Class                         = lunpath
Instance                      = 16
Hardware path                 =
42/0/0/2/0/0/0/4/0/0/1.0x5006048ad5f116c0.0x4022000000000000
SCSI transport protocol       = fibre_channel
State                         = FAILED
Last Open or Close state      = DISABLE_OPENS

Cause

Starting with VxVM 5.0, a new tunable is introduced called “dmp_cache_open”. As described, when set to “on”, the first open of a device that is performed by an array support library (ASL) is cached. This enhances the performance of device discovery by minimizing the overhead caused by subsequent opens by ASLs. If set to “off”, caching is not performed. With open cache enabled, DMP ensures that there is no re-assignment of device numbers.

For VxVM 5.0/11.31 systems, it is recommended dmp_cace_open be turned ON  (enabling “DMP open caching”). Please also  see   http://www.symantec.com/business/support/index?page=content&id=TECH76872 for further information.

 

After the hardware snapshot operations, for non VxVM LUNs, VxVM retains the failed state of the device,

even after the LUN becomes Read Write mode. This caching of failed state, causes the LVM VG operations

to fail with Device Busy error.

 

Solution

With mixed  LVM volume groups and VxVM diskgroups environments, Veritas recommends to exclude the non VxVM LUNs from VxVM's view.

This avoids the device open caching and LVM operations will succeed properly.

To exclude the LVM LUNs from VxVM view, we suggest below procedure.

1. Run vxdiskadm

2. Select option #17 (Prevent multipathing/Suppress devices from VxVM's view).

3. Select option 4 (Suppress all paths to a disk).

4. Enter the LVM disk name to be excluded (Get the device name from vxdisk list output)

5. Verify the device exclution

After the device is excluded from VxVM view using the 'vxdiskadm' utility, "/etc/vx/vxvm.exclude" file is updated

as below.

 
# cat /etc/vx/vxdmp.exclude
exclude_all 0
paths
c11t0d5 1/0/12/1/0.0x500009720860bda5.0x4005000000000000
#
controllers
#
product
#
 

Applies To

OS version:        B.11.31.1403.401a Feature Enablement Patches for HP-UX 11i v3, March 2014

VxVM versions:  5.0.31 and above.

Storage array:    EMC SYMMETRIX

 

References

Etrack : 3667574

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