Data Domain: Intermittent panics when ingesting data using NFSv4 with the default NFS options

The DD FS process may experience intermittent PANICs, dump core and restart, when ingesting data using NFSv4 with the default NFS options. This occurs if running earlier DDOS 6.1.x releases, with PANIC strings such as the following:

ERROR: MSG-INTRNL-00001: PANIC: ddr/nfs4/nfs4_idmap/nfs4_names.c: _perform_timed_lookup: 698: !(active_cookie->magic == NFS4_IDMAP_LOOKUP_ARG_USED).

N/A

The defect has been fixed in the code for the following DDOS releases:

• DDOS 6.1.1.1 and later
• DDOS 6.1.2.0 and later

If a customer cannot upgrade immediately or releases are unavailable, a workaround may be possible, but the issue must first be confirmed as the one described.:

• Are any non-root users used to perform I/O on the NFSv4 mount on clients?
• Is NFSv4 ID mapping on the client is enabled? On Linux, run "cat /sys/module/nfs/parameters/nfs4_disable_idmapping" to find out.
• Is the NFS client using Kerberos security (sec=krb5) for any NFSv4 export?
• Are there NFSv4 ACLs being used?

If all the above answers are "NO," an immediate workaround is to disable NFSv4 ID mapping on the DDR using the DD CLI command below:

# nfs option set nfs4-idmap-out-numeric always

This ensures that the code path that caused the PANIC is not reached, and causes no issues with normal backups due to them not using any of the features in the "prechecks" mentioned above.

After a customer upgrades to a fixed release, this setting should be reset:

# nfs option reset nfs4-idmap-out-numeric