*BSD News Article 34722


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Path: sserve!newshost.anu.edu.au!munnari.oz.au!spool.mu.edu!howland.reston.ans.net!EU.net!uknet!festival!edcogsci!richard
From: richard@cogsci.ed.ac.uk (Richard Tobin)
Subject: Re: Whats wrong with Linux networking ???
Message-ID: <CutxxH.4Is@cogsci.ed.ac.uk>
Organization: HCRC, University of Edinburgh
References: <michaelv.776931077@ponderous.cc.iastate.edu> <32ovqa$933@wombat.cssc-syd.tansu.com.au> <32pef4$8ao@u.cc.utah.edu>
Date: Sat, 20 Aug 1994 10:46:27 GMT
Lines: 26

In article <32pef4$8ao@u.cc.utah.edu> terry@cs.weber.edu (Terry Lambert) writes:
>] Is there a way to turn off synchronous writes of meta data in *BSD?

>Does anyone else read this as "How Do I Poke Myself In The Eye"?

Not me.  I certainly wouldn't want to do it all the time, but in some
situations it's worth the risk.  For example when restoring a file
system, turning off synchronous metadata writes can speed up the
restore by a factor of 10.  A two hour restore takes about 15 minutes.
If you're restoring onto an empty filesystem, it's definitely worth
it; the system could crash several times before it's slower than the
original.  Or consider the situation I'm currently in after our file
server was down for three days: we have about 10^5 news articles to
unbatch.  This runs at about 4 articles/sec with sync writes on, 10
articles/sec with sync writes off.  If it fails, all we've lost is
some news.

SunOS (and I believe some other unixes) have an ioctl for this;
adding it to *BSD would be worthwhile.

-- Richard
-- 
Richard Tobin, HCRC, Edinburgh University                 R.Tobin@ed.ac.uk

Ooooh!  I didn't know we had a king.  I thought we were an
autonomous collective.