*BSD News Article 74128


Return to BSD News archive

Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mira.net.au!Germany.EU.net!main.Germany.EU.net!Frankfurt.Germany.EU.net!howland.reston.ans.net!nntp.coast.net!news.kei.com!newsfeed.internetmci.com!malgudi.oar.net!hyperion.wright.edu!echoes.wittenberg.edu!bob.wittenberg.edu!mandrews
From: mandrews@bob.Wittenberg.EDU (Mike Andrews)
Newsgroups: news.software.nntp,comp.unix.bsd.freebsd.misc
Subject: Re: FreeBSD 2.1.5, INN 1.4unoff4, and mmap()
Date: 18 Jul 96 12:38:40 GMT
Organization: Wittenberg University, Springfield OH
Lines: 46
Distribution: inet
Message-ID: <mandrews.837693520@bob.wittenberg.edu>
References: <mandrews.837437077@bob.wittenberg.edu> <4sdk50$9cp@news.demos.su> <4sdndm$27k@brasil.moneng.mei.com> <4se8tq$sgf@news.demos.su> <4sg80v$3uu@brasil.moneng.mei.com> <4sggo5$ls@news.demos.su>
NNTP-Posting-Host: bob.wittenberg.edu
X-Newsreader: NN version 6.5.0 #8 (NOV)
Xref: euryale.cc.adfa.oz.au news.software.nntp:24503 comp.unix.bsd.freebsd.misc:23905

andy@sun-fox.demos.su (Andrew A. Vasilyev) writes:

>Joe Greco (jgreco@brasil.moneng.mei.com) wrote:
>> My point was why would you care about overall disk bandwidth, so why would
>> you run a bandwidth test?

>  Only to say that there is big gap: metadevice speed vs FS speed.
>  I hope the optimisation will be done: ccd is very young now :)

>> "~S"?
>> If you mean the size of the article, you are wrong.

>  Could you provide the theoretical value of stripe size for multiple
>  reading/writing of small files?

>> No, you're forgetting - to retrieve an article requires multiple accesses.
>> You need to do multiple directory lookups, etc.  If you really think about

>  Well - here is the weakness of FreeBSD FS: when you access the file
>  in a large directory in Solaris the lookup goes from the cache, you
>  say in Free too, but the tests show that the efficiency of its cache
>  is worse than of Solaris. So multiple lookups should not worry you
>  on well-written FS :)

>  So if we return to the thread start: in FreeBSD we have buggy mmap()
>  and soggy ccd together with not so good directory cache. All these
>  cause me to say the better platform for heavy loaded news server is
>  Solaris. :((

Well, the thread wasn't about FreeBSD vs. Solaris...

The thread was mostly about "can I use mmap()", and it seems I still can't.
I can deal with waiting for 2.2.

As far as optimal stripe size...  this is not a "heavily loaded" news server.
We are an end node with only one tiny partial outgoing feed, so it makes more
sense to optimize for multiple article writes instead of reads.  I set it
up for a stripe size of 116 instead of 65536 (mostly because I read Joe's
message too late :)  and it seems to be pretty speedy, even though it's
optimized for overall throughput and not optimized for news's special needs.
We'll see...

-- 
-- Mike Andrews  -  mandrews@wittenberg.edu, mandrews@termfrost.org (NeXT)
-- Programmer/Analyst, systems/mail/web/netnews guy, Wittenberg University
-- http://www.termfrost.org/~mandrews/                            "why..."