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From: arisawa <arisawa@ar.aichi-u.ac.jp>
In-Reply-To: <41f95d8dba3fa0a675fbc54e151ba844@kw.quanstro.net>
Date: Tue,  5 Mar 2013 17:55:45 +0900
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Message-Id: <BF86FE5E-4EA3-4330-BA78-4DAC6F632CC3@ar.aichi-u.ac.jp>
References: <7E48F293-1D27-4958-BB64-BDDC490CB7E7@ar.aichi-u.ac.jp>
	<41f95d8dba3fa0a675fbc54e151ba844@kw.quanstro.net>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] dirty blocks in cwfs
Topicbox-Message-UUID: 2396fcd6-ead8-11e9-9d60-3106f5b1d025

thanks erik,

> the "t" bit that 9front added
how to do?
I don't know this one.

I analyzed map area in fscache and then found:
corresponding worm blocks of dirty cache blocks are garbage.

On 2013/03/05, at 15:22, erik quanstrom <quanstro@quanstro.net> wrote:

> On Tue Mar  5 01:03:23 EST 2013, arisawa@ar.aichi-u.ac.jp wrote:
>> Hello,
>>=20
>> It seems my cwfs has too many dirty blocks.
>> cfws command ("dump", "check tag" and etc) is no help to decrease =
these blocks.
>> is this only to me?
>=20
> i have not seen this with kenfs.  is it possible that you
> are using the "t" bit that 9front added?  if so, that would
> explain all the dirty blocks that never get dumped.
> one also ends up with dirty superblocks that can't get
> dumped because they're already written, about 1 per
> day in the dump.
>=20
> one thing i notice about your cache-worm is that the
> cache is very large.  this is not advisable because your
> cache buckets will take up too many memory buffers,
> leaving little for actual data.  20G cache has been
> enough.  the first big file server i set up had 750G
> cache, and it thrashed the heck out of its disks.
>=20
> - erik
>=20