High Load average no CPU utilization

adam fisher afisher at circlepix.com
Wed Mar 28 16:30:07 MDT 2007


This is the mount statement for our BSD boxes and the fedora box.

10.11.1.91:/data/online          /mnt/online    nfs     rw,port=2049,intr    0    0

We then have a /online ->/mnt/online

Fedora says the default is v2.

I am not sure what the 0   0 are doing at the end of the mount but they were on the freebsd boxes so I just left them.

Is there away to make sure that we are allowing enough connections on the NFS server?

let me know what you see.

thanks,
Adam


----- Steve Alligood <steve at bluehost.com> wrote:
> it may be HOW you are mounting it, and how fedora versus BSD defaults
> to 
> mount it.
> 
> nfs v2 will be really quick, but not as reliable for data writes (aka,
> udp)
> 
> nfs v3 will be more reliable (tcp) but slower
> 
> nfs v4 will be reliable (tcp) and secure (encrypted) but a lot slower
> 
> Fedora may default to v4 while your BSD does v3 or v2.
> 
> 
> I have some mounts I use nfs v2 because I am not as worried about
> writes 
> and I need the speed.  I also change the read and write window sizes,
> 
> and turn off atime checking:
> 
> async,soft,noatime,intr,nfsvers=2,rsize=8192,wsize=8192
> 
> Of course, the server must support the v2 nfs as well (obvious, but 
> worth mentioning)
> 
> -Steve
> 
> adam fisher wrote:
> > I appreciate everybody's thoughts on this.
> > 
> > I agree that the NFS looks to be the bottle neck however we have 5
> other load balanced web servers that are pulling the web data from our
> NFS server.  We mount the partition and then created sym links to
> those mounts.  The other 5 web boxes are up and running fine.  It is
> the sixth alone that is having this issue.
> > 
> > The first 5 are BSD this is a Fedora installation as we want to get
> away from BSD.  
> > 
> > Any other ideas?
> > 
> > thanks,
> > Adam
> > 
> > 
> > ----- Ryan Simpkins <plug at ryansimpkins.com> wrote:
> >> On Wed, March 28, 2007 11:44, adam fisher wrote:
> >>> apache   17268  0.7  0.6  29552 12868 ?        D    04:27   0:04
> >> /usr/sbin/httpd
> >>> apache   17456  1.1  0.6  29728 13168 ?        S    04:27   0:06
> >> /usr/sbin/httpd
> >>> apache   17890  0.5  0.6  29928 12588 ?        D    04:28   0:02
> >> /usr/sbin/httpd
> >>> apache   17893  0.0  0.5  29032 11548 ?        D    04:28   0:00
> >> /usr/sbin/httpd
> >>> apache   17895  0.0  0.5  29184 11716 ?        D    04:28   0:00
> >> /usr/sbin/httpd
> >>> apache   17896  0.0  0.5  28740 11256 ?        D    04:28   0:00
> >> /usr/sbin/httpd
> >>> apache   17897  0.0  0.5  28912 11452 ?        D    04:28   0:00
> >> /usr/sbin/httpd
> >>> apache   17904  0.3  0.5  29288 11876 ?        D    04:28   0:01
> >> /usr/sbin/httpd
> >>> apache   17913  0.5  0.5  29316 11892 ?        D    04:29   0:02
> >> /usr/sbin/httpd
> >>> apache   17923  0.1  0.5  29364 12052 ?        D    04:29   0:00
> >> /usr/sbin/httpd
> >>
> >>> Device:         rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s
> >> avgrq-sz avgqu-sz
> >>> await  svctm  %util
> >>> sda               0.00    11.00  0.00  6.00     0.00   136.00   
> >> 22.67     0.00
> >>> 0.50   0.17   0.10
> >>> The web root is located on an NFS share.  I restarted NFS on this
> >> box just to make
> >>> sure.  When I restart httpd and the load average drops to around
> 10
> >> or 11 I can
> >>> browse the webpage just fine.  It is when it gets to around 150
> that
> >> I can't.
> >> Bingo. Your web root is running over NFS. NFS is pure evil for
> this
> >> type of work.
> >> You may be able to improve performance playing around with the
> various
> >> NFS mount
> >> options.
> >>
> >> -Ryan
> >>
> >> /*
> >> PLUG: http://plug.org, #utah on irc.freenode.net
> >> Unsubscribe: http://plug.org/mailman/options/plug
> >> Don't fear the penguin.
> >> */
> > 
> >


-- 
Adam Fisher
IT Coordinator
CirclePix
801-318-4585 ext.6603
1-877-390-6630 ext.6603




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