Linux: DB Processes may hang when running large "dd" to NFS disk, leading to RAC eviction or crash (Doc ID 1512914.1)

Last updated on AUGUST 04, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.1 and later
Information in this document applies to any platform.

DB processes (or any other OS process) may hang or stall in nfs_wait channel while an OS process is creating a large file over NFS using "dd".

In RAC, this can mean a stalled background process which in turn leads to instance termination or instance eviction.

Creating a large zero-padded file over NFS using "dd" WITHOUT using the "oflag=direct" option.

eg:

oracle>dd if=/dev/zero of=/oracle/asm/disks/nfsdisk2 bs=8192 count=100000
100000+0 records in
100000+0 records out

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In this Document

Symptoms

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