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Date:      Sun, 12 Jan 1997 12:34:40 -0700 (MST)
From:      Terry Lambert <terry@lambert.org>
To:        henrich@crh.cl.msu.edu (Charles Henrich)
Cc:        terry@lambert.org, freebsd-hackers@FreeBSD.org
Subject:   Re: mount -o async on a news servre
Message-ID:  <199701121934.MAA26007@phaeton.artisoft.com>
In-Reply-To: <199701121905.OAA13998@crh.cl.msu.edu> from "Charles Henrich" at Jan 12, 97 02:05:53 pm

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> > You seem to be confusing "noatime" with "async".  The "async" option
> > acts pretty much as you describe.
> 
> You've misread what I said.  Using atime with sync's done every 300
> seconds I would beleive is very similar in performance to async,
> without the risks.  This is of course only in the case of a news spool.

Ah... you are claiming the only metadata events for a read-only news
spool are atime related.

I agree with you, then...

> > You could rephrase this as "Is there any safe way to run 'async'?",
> > with the answer being "Yes, if you only read from, and never post
> > directly to, the 'async' server".
> 
> No No, perhaps I wasnt clear.  I was never advocating running async, its a big
> bad idea IMHO.  I was attempting to show that running with noatime and sync's
> pushed back to be infrequent (300 seconds) you get nearly the performance win
> of async, without the risks..

The "noatime" means "noatime", not "async atime".

I think changing the sync frequency for update will have no effect,
unless theres a conflict with the free buffer high water mark.  Even
so, if that happened, then you are trading update time for blocking
access to buffers for some users (assuming the reclaim high water
mark is set correctly, which I believe it is).


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.



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