VDB is failing to start, reports error ORA-03135: connection lost contact

Problem

Trying to start VDB

The VDB is starting, after 1-2 minutes it fails with ORA-03135: connection lost contact

The alert.log shows that control file fails on I/O. Manual list or change of the control file via shell works fine.

ORA-00221: error on write to controlfile
ORA-00206: error in writing (block 3, # blocks 1) of controlfile
ORA-00202: controlfile: '/main_pool/5120325725/data/control.dbf'
ORA-27072: File I/O error
Linux-x86_64 Error: 5: Input/output error
Additional information: 4
Additional information: 3
Additional information: -1
CKPT (ospid: 16341): terminating the instance due to error 221
System state dump requested by (instance=1, osid=16341 (CKPT)), summary=[abnormal instance termination].
System State dumped to trace file /main_pool/5120325725/diag/rdbms/00317254/00317254/trace/00317254_diag_16329.trc
Dumping diagnostic data in directory=[cdmp_20240331103744], requested by (instance=1, osid=16341 (CKPT)), summary=[abnormal instance termination].
Instance terminated by CKPT, pid = 16341

Another error that may appear in the alert.log is:

ORA-27061: waiting for async I/Os failed

Solution

The mount options are incorrect.

Goto Target Host configuration, set mount options to:

-t nfs -o rw,bg,hard,nointr,rsize=32768,wsize=32768,tcp,vers=3,timeo=600,nolock

An additional solution is to clear the mount options completely, in this case the app will use defaults which are the same as the above line