High I/O Latency reported by OEM during 11.2.0.4 RAC dNFS Database Imports (Doc ID 2104264.1)

Last updated on FEBRUARY 22, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.2 and later
Information in this document applies to any platform.

Symptoms

11.2.0.4.8 -- Linux x86-64(rhel6) -- 10G Ethernet over to NetApps server

OEM reports (under I/O tab) several I/O peaks and latencies (<=1600 ms) during RAC dNFS database Imports, for some sustain time (5~10 minutes). See screen shot attached.
If dNFS is disabled, OEM reports latencies under 1ms for the same database Import.

The same high I/O latencies, are not present in AWR reports, or monitoring reports done at the storage level.

Cause

Sign In with your My Oracle Support account

Don't have a My Oracle Support account? Click to get started

My Oracle Support provides customers with access to over a
Million Knowledge Articles and hundreds of Community platforms