Re: RAIDframe level 5 write performance

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Fri, Nov 02, 2012 at 11:06:33PM +0100, Edgar Fu? wrote:
> > What does file write performance look like with WAPBL turned off?
> Well, I havent' tried dd'ing to a file with WAPL turned off, but the figures 
> for creating a lot of files can be found further up in this thread:
> > On the 8k fsbsize FFSv1, it takes 7 seconds with WAPL and 5 without!

I think you're seeing pathological cache flush behavior.  Does this
controller have a nonvolatile cache?  It does, right?

I bet with every WAPBL transaction, it's flushing the whole thing,
even though it doesn't need to.

What happens if you set the cache to write-through for the logical
volume?

-- 
 Thor Lancelot Simon                                          
tls%panix.com@localhost
   But as he knew no bad language, he had called him all the names of common
 objects that he could think of, and had screamed: "You lamp!  You towel!  You
 plate!" and so on.              --Sigmund Freud