Subject: Re: sysctls for everything!
To: Erik Rungi <>
From: Greg Oster <>
List: tech-kern
Date: 06/13/2000 09:31:10
Erik Rungi writes:
> Hiya,
> When 1.4 was released I did some bonnie benchmarks on a fresh 2 drive SCSI
> system with striping.  In all the tests I tried, the ccd device was faster
> than the raid device in almost all categories.

For a 2-component stripe ccd may be faster.  With more components, it's 
harder to say...  Depending on the configuration, RAIDframe may actually 
outperform ccd on 4-5 component sets... (not by much though :) )

> I don't know know if thats changed since then, but based on what I saw ccd is
> worth keeping around because its faster, as well as allowing for a
> considerably smaller kernel size.

It's worth keeping around because it can do concatenation, which RAIDframe 
cannot, and it's also a lighter-weight way of doing simple striping.
> Well, I lost all the data that I had saved (it was a while ago), but I swear
> its true.  I think I have the numbers backed up offline somewhere if anyone is
> interested.

If you happen to stumble across them sometime, I'd be interested in seeing 
them... but don't make a special effort to get them.

> On Mon, 12 Jun 2000, Allen Briggs wrote:
> > > On Tue, 13 Jun 2000, Simon Burge wrote:
> > > 
> > > > On a slightly related note, are we planning on keeping ccd's around now
> > > > that we have RAIDframe?  Admittedly a ccd is a lot more light-weight
> > > > than RAIDframe if all you want it a stripe/concat.
> > 
> > On Mon, Jun 12, 2000 at 06:45:24PM -0700, Bill Studenmund wrote:
> > > I hope not. Their light weight can be useful. :-)
> > 
> > I agree with what I believe Bill's intent to be, not his statement.
> > I hope we are planning on keeping ccds around because their light
> > weight can be useful.


Greg Oster