Re: Bcache Journal

From: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: James Sefton <james-3k2nYdb70uTQXOPxS62xeg@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: Bcache Journal
Date: Fri, 2 Nov 2012 08:16:21 -0700	[thread overview]
Message-ID: <20121102151620.GB14917@google.com> (raw)
In-Reply-To: <loom.20121102T043837-976-eS7Uydv5nfjZ+VzJOa5vwg@public.gmane.org>

On Fri, Nov 02, 2012 at 03:44:00AM +0000, James Sefton wrote:
> Alex Pyrgiotis <apyrgio@...> writes:
> 
> > 
> > On 10/29/2012 10:43 PM, Kent Overstreet wrote:
> > > On Sun, Oct 28, 2012 at 06:20:19PM +0200, Alex Pyrgiotis wrote:
> > >> Hi,
> > >>
> > >> In the wiki, it is mentioned that bcache can run either with or
> > >> without a journal.
> > >> What I'd like to ask is which is the default bcache configuration
> > >> (journal on|off?) and is there an option in the make-bcache tool to
> > >> change this configuration?
> > > That's out of dat... What page did you find that on? Running without a
> > > journal hasn't been an option in ages...
> > Hi Kent,
> > 
> > Here's the link: http://bcache.evilpiepirate.org/Design#Journal
> > The out-dated part is "It is possible to create cache devices..."
> > >
> > > (You wouldn't want to run without the journal, it's there to improve
> > > performance)
> > Yeah, I know. Just wanted to have a look at bcache's knobs and switches...
> > Thanks again. 
> > 
> 
> 
> Hi Kent,
> 
> Out of interest - I am also having trouble with the docs and I am getting them 
> from the same server as Alex.
> 
> http://evilpiepirate.org/git/linux-bcache.git/tree/Documentation/bcache.txt
> 
> Just wondering if we are both looking in the wrong place??
> 
> The docs seem to be outdated somewhat.
> As an example there is a list of sysfs entries described at the bottom of the 
> page.  A lot of these either do not exist or have changed names, and a lot of 
> new ones seem to be added that are not listed in the docs.
> 
> Is this site the wrong place to be looking or are the docs simply out of date?

That's the right place, some of that is out of date though. I think it's
_mostly_ the sysfs stuff.

> (If the docs are out of date then maybe we can help you maintain them.)

Please do! All the documentation should be in the kernel tree, so you
can just send me patches for that. Any questions about what it should
say, go ahead and ask.