Troubleshooting
Problem
This technote documents the root cause and resolution of two related incidents where an IBM Hardware Management Console (HMC) failed to complete a backup (bkconsdata) to an AIX NFS server. The failures manifested as HSCLA505 and HSCLA506 errors. The issues were traced to (1) an NFS version mismatch between the export and the server-side mount, (2) missing explicit client authorization in the NFS export. Correcting the export configuration and explicitly authorizing the HMC IP resolved the issue.
Symptom
Symptom 1: HSCLA505 – Mount failure
The HMC failed to mount the remote NFS filesystem during the backup operation.
Observed error on the HMC:
HSCLA505 An error occurred while trying to mount the remote NFS file system.
Symptom 2: HSCLA506 – Write failure
After a successful mount attempt, the backup failed during the write phase.
Observed error on the HMC:
HSCLA506 An error occurred while trying to write a file to the mounted NFS file system.
Cause
HSCLA505 (Mount Failure)
The HMC attempted to mount the NFS export using NFSv4 while the export was restricted to NFSv3 only. This mismatch caused the HMC mount operation to fail.
The filesystem was initially exported as NFSv3:
/mksysb_all -vers=3,sec=sys,rw,access=*,root=*
While the filesystem was mounted using NFSv4:
10.50.4.114:/mksysb_all /mksysb-backup nfs4 vers=4
Corrective Action
Updated the export definition to allow both NFSv3 and NFSv4:
/mksysb_all -vers=3:4,sec=sys,rw,access=*,root=*
Then reloaded the export with the following:
exportfs -u mksysb_all
exportfs -i mksysb_all
exportfs -av
After this step, the export update succeeded, and the HMC was able to mount the filesystem.
HSCLA506 (Write Failure)
Although the HMC could now mount the filesystem, write operations failed.
The HMC bkconsdata operation performs privileged file system operations on the remote NFS server. The NFS export must permit root access from the HMC system to allow successful write operations.
Corrective Action
The NFS export was updated to explicitly authorize the HMC IP address:
/mksysb_all -vers=3:4,sec=sys,rw,access=<HMC_IP>,root=<HMC_IP>
The export table was then reloaded:
exportfs -u mksysb_all
exportfs -i mksysb_all
exportfs -av
After this change:
The HMC was able to mount /mksysb_all
The HMC successfully wrote the backup data
The bkconsdata operation completed successfully
Environment
- Client: Hardware Management Console (HMC)
- Server: AIX NFS server
- Protocol: NFS (v3 and v4)
- Backup method: bkconsdata -r nfs
Document Location
Worldwide
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Document Information
Modified date:
23 February 2026
UID
ibm17259418