SUMMARY: noac-option

From: Robert Schreiber (
Date: Mon Mar 20 1995 - 21:57:53 CST

Hi Managers,
Mounting with "-noac" means "NO Attribute Caching".
That means, if the nfs-client wants to get an attribute of an nfs-mounted file,
it shall skip the query of a cached list of attributes held on the nfs-client
and directly get it from the nfs-server.
 It is normally used on filesystems that do a lot of file or record locking
e.g. /var/mail.

We 'll have to use this option until a SUN patch can be delivered, because
our application uses file locking and looses data if file systems are
mounted without noac on Solaris 2.4.

Thanx to:
Kev, Matt, Kai, Christopher and Faraut

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From: (Kevin Sheehan {Consulting Poster Child})

A good drop in performance usually :-)/2 Caching attributes allows
the client to not ask for information about files from the server
so often. Turning it off closes the window of opportunity for a file's
attributes to change and you not noticing, but it means you talk to
the server for it every time instead of using a local copy.

>From matt@uts.EDU.AU Sat Mar 18 08:26:47 1995

noac == no attribute caching.. it is normally used on filesystem that
make heavy use of file or record locking (like /var/mail etc).


echo '16i[q]sa[ln0=aln100%Pln100/snlbx]sbA0D3F204445524F42snlbxq'|dc;exit

>From Sat Mar 18 09:52:27 1995

I think:

When NFS mounting a file system, the client caches attributes. This is a problem with concurrent accesses to a file system (like if you NFS-mount /var/spool/mail where you'll get all kinds of timing problems if you aren't careful).

This may be all wrong...

>From Sat Mar 18 10:57:31 1995

It suppresses directory caching, which speeds things up if your are always accessing files by name on a file system.. I use it for the global mail spool for example..

>From Mon Mar 20 10:02:51 1995

Use -noac for NFS-mounted system mail partition: /var/mail or /var/spool/mail, your mileage may vary.

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