mkvdev error "0514-047 Cannot access a device." or "Cannot open a file or device."

Troubleshooting

Problem

mkvdev command fails when attempting to configure the second VSCSI MPIO path.

Symptom

$ mkvdev -vdev hdisk# -vadapter vhost#
Method error (/usr/lib/methods/cfg_vt_scdisk):
    0514-047 Cannot access a device.

or

$ mkvdev -vdev hdisk# -vadapter vhost#
Cannot open a file or device.

Cause

The VIOS is not able to access the target device, e.g. hdisk#, specified with -vdev flag.

Environment

VIOS 3.1 and 4.1 and VSCSI backed by SAN storage.

Diagnosing The Problem

VSCSI requires read-write access to the target device being virtualized.

Determine if the VIOS is able to access the backing device. Login to VIOS as padmin, and run:

$ oem_setup_env
# dd if=/dev/hdisk# of=/dev/null count=1000

Expected output should look something like this:

1000+0 records in.
1000+0 records out.

Error message "The requested resource is busy." is indicative of the backing device having some kind of reserve.

If dd command comes back to the prompt (with no output), that indicates the VIOS is not able to access the device at all.

Resolving The Problem

If the configuration involve VSCSI MPIO configuration, (this means the same SAN disk is configured on both VIOSes), the SAN disk must have the reserve_policy set to no_reserve on both VIOSes. To check the disk attribute, run:

$ lsdev -dev hdisk# -attr reserve_policy

If one VIOS has the reserve policy set to single_path and the other one is set to no_reserve, refer to How to change reserve policy on one of two VIO Servers.

If both VIOSes have the reserve_policy already set to no_reserve, next, examine the VIOS error log using errlog command for "RESERVATION CONFLICT" errors and contact your Storage Support Representative for assistance clearing the disk reservation.

Example:

Aug 6 16:32:05 hdisk536 P SC_DISK_ERR10 path 0 cmd failure READ(10) (00000007,0001) RESERVATION CONFLICT [state ONLINE|PENDING_ERROR|

If dd command returned no output, contact your Storage Support Representative to verify storage provisioning to the VIOS host.

Retry mkvdev after dd command returns the expected output.

Related Information

Multipathing and disk resiliency with VSCSI in a dual VIOS configuration

Document Location

Worldwide

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