nginx workers in "D" status in top

[Ryan Malayter]

On Tue, Jul 27, 2010 at 12:22 PM, Joaquin Cuenca Abela
<joaquin at cuencaabela.com> wrote:
> I has this problem before, somehow nginx was blocking on access to a
> NFS partition that was saturated. Check if you have any link
> whatsoever with a saturated disk, and pay special attention to NFS
> partitions.

No NFS involved at all, but I suppose it is possible the disk is being
saturated (even though it is actually a very fast SAN volume). I will
have to check on that, but if the IO is asynchronous the nginx workers
should not get into the "uninteruptible sleep" sate.

That said, I do get frequent large requests and responses being
spooled to temporary files on disk. Those should all be handled by
filesystem cache, but I wonder if nginx doesn't use async IO for those
processes.

I also suppose it could be access logging... this is a very busy
system (handling > 100 requests per second). Does the access log not
use async IO?

-- 
RPM