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Operating Systems AIX Slow NFS when cio/dio enabled Post 302589286 by Z80A on Wednesday 11th of January 2012 08:07:11 AM
Old 01-11-2012
With A61 it should not be necessary any more to explicitly use the cio mount option.

If your db is DB2 or Oracle this should rather be activated at the db profile level, e. g. using < filesystemio_options = SETALL > for Oracle.

Simply spoken, cio and dio options are effectively bypassing filesystem caching and read-ahead logic causing severe performance hits for any 'normal' application.

Hope this helps.
Regards
Greg
 

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SHOWMOUNT(8)						    BSD System Manager's Manual 					      SHOWMOUNT(8)

NAME
showmount -- show remote nfs mounts on host SYNOPSIS
showmount [-a | -d] [-e] [-1] [-3] [host] DESCRIPTION
The showmount utility shows status information about the NFS server on host. By default it prints the names of all hosts that have NFS file systems mounted on the host. See NFS: Network File System Protocol Specification, RFC 1094, Appendix A, and NFS: Network File System Version 3 Protocol Specification, Appendix I, for a detailed description of the protocol. The following options are available: -a List all mount points in the form: host:dirpath. -d List directory paths of mount points instead of hosts. -e Show the host's exports list. -1 Use mount protocol Version 1, compatible with legacy servers. -3 Ignored for backwards compatibility. SEE ALSO
mount(8), mount_nfs(8), mountd(8) HISTORY
The showmount utility first appeared in 4.4BSD. BUGS
The mount daemon running on the server only has an idea of the actual mounts, since the NFS server is stateless. The showmount utility will only display the information as accurately as the mount daemon reports it. BSD
August 16, 2014 BSD
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