nginx workers in "D" status in top

Joaquin Cuenca Abela joaquin at
Tue Jul 27 21:22:37 MSD 2010

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

On Tue, Jul 27, 2010 at 6:54 PM, Ryan Malayter <malayter at> wrote:
> I'm seeing a number of workers periodically entering the "D" status in
> top (uninteruptible sleep). Normally, this means it is blocking on
> disk IO. However, I am using nginx 0.7.62 (default package) on Ubunutu
> 9.10, and I believe asynchronous IO should be enabled.
> We are using proxy_cache, so there is some reading from disk in our
> configuration (not just reverse proxy).
> Is it normal to have nginx workers block on the disk even on an
> asynchronous IO-capable system?
> How can I check if nginx is actually using async IO?
> My configuration is large, but I will post fragments if necessary. I
> am using 4 worker processes on a single-CPU system (recently upped to
> 10 because of this issue).
> Thanks,
> --
> _______________________________________________
> nginx mailing list
> nginx at

Joaquin Cuenca Abela

More information about the nginx mailing list