Subject: Re: Problem with second 3Ware Escalade
To: Arne Kaiser <kaiser@hauptsache.net>
From: Andrew Doran <ad@netbsd.org>
List: netbsd-help
Date: 03/16/2007 04:20:38
> I just installed a second 3ware escalade 8006 controller in a Netbsd 2.0.2
> system (AMD 64). The first on runs fine since several month with two
> mirrored 250 GB harddisks, the second (with two 50 GB HDs) seems to be
> fine,
> but when I start newfs /dev/ld1e the formatting process is extremely slow
> and all services stop working (ssh httpd smbd). due to the fact that the
> system is a production server I had to cancel newfs but I need the new
> Volume urgently.

Did you run vmstat, top or similar while this was happening? What did
the user/system/idle time and interrupt rate look like?

The 3ware controller needs all transfers aligned on a 512-byte boundary.
That's OK for usual file system access since all the transfers are
aligned naturally. newfs accesses the raw device so the transfers go
directly from the card to user memory, and the buffer can be unaligned.

The driver has to double buffer for unaligned requests. That could be the
problem that you are running into. Ideally we should have a fixed buffer
so that there's only 1 unaligned transfer at a time going.. I don't have
one of these controllers any more to test with, but if someone can test
I'll have a go at making the changes. It would be good to see the numbers
to make sure that is what's happening though.

Cheers,
Andrew