RE: Performance Difference Between Linux NFS Server and Netapp

["Roger Heflin" <rheflin@atipa.com>]

Locally disk cache will cause the results to be junk,
locally the cache will be used, with NFS the cache
will not be used for writes.

With Suse 9 Enterprise and a disk subsystem that will
sustain rates of 125MiB/second I can get write rates of
95MiB/second and read rates of 115MiB/second, this is
with sustained over 12 minutes of writes.

2000mbit/second is a rate that no ide disk subsystem
will obtain, so double check your local performance, 
if it is fast single disk it will get 50mb/second, if
you are using a built-in ata controller, with all channels
having fast disks you won't be able exceed 90mb/second
no matter what disk you use or how many or how you stripe
them, as the build-in mb controllers are not the best, 
and this is on the  more expensive dual-cpu mbs, it may
be worse on the single cpu machines.

You will need to use a test larger than the ram size of 
the machine to get a realistic rate, at least 2x, and
probably 4x, and maybe both just to see how things fall
over.

                         Roger

> -----Original Message-----
> From: nfs-admin@lists.sourceforge.net 
> [mailto:nfs-admin@lists.sourceforge.net] On Behalf Of Hugh Caley
> Sent: Monday, July 11, 2005 5:56 PM
> To: nfs@lists.sourceforge.net
> Subject: [NFS] Performance Difference Between Linux NFS 
> Server and Netapp
> 
> I've been doing a little limited benchmarking of NFS 
> performance, and doing a comparison between Linux NFS servers 
> and a Netapp.  All tests done over gigabit, clients are Linux 
> (i386 and Opteron), OS is Fedora Core 2, kernel is 
> 2.6.10-1.771_FC2smp, filesystem is Reiser.  I basically copy a
> 205
> megabyte file to the server three times and average the 
> results.  Sure, limited, but it seems to have real world 
> relevance here.
> 
> The difference in performance is kind of startling.  I had 
> originally put the Linux-based servers (with a Nexsan 
> Atabeast backend) in as a replacement for an older EMC 
> Celerra and a few older Suns.  On both the Suns and Celerra I 
> would see single-client performance topping out at between 
> 120 and 150 megabits per second.
> 
> The Linux setup (Supermicro Dual 2.6 Ghz Xeons with 4 
> gigabytes of RAM, recently boosted to 8 gigabytes of RAM) 
> regularly returns about 300 megabits per second.  Given the 
> difference in price between the Linux boxes and the Celerra, 
> everyone's pretty happy ;)
> 
> However, recently I've been trying the same testing between 
> Linux clients and a Netapp, and can achieve between 500 and 
> 600 megabits per second!  Darned impressive.
> 
> I realize that the disk subsystem of the Netapp is going to 
> stomp on my Atabeast, but neither 300 nor 600 megabits is 
> anywhere near the speed I can get if I run the same test 
> locally on the Linux server boxes, which can regularly top 
> 2000 megabits per second, so I really don't think that the 
> differences in disk architecture should make this much difference.
> 
> I guess my question is, are my Linux NFS servers seriously 
> underperforming?  Could I expect to achieve better?  I 
> realize that my "benchmark" is pretty limited, but the 
> difference is pretty big.  Since the same client on all the 
> Linux boxen gets these results, I'm guessing that the client 
> end has little to do with it.
> 
> How does Netapp do it?  Don't suppose they'd tell me ...
> 
> Hugh
> 
> --
> Hugh Caley | Unix Systems Administrator | CIS AFFYMETRIX INC. 
> | 6550 Vallejo St. Ste 100 | Emeryville, CA 94608
> Tel: 510-428-8537 | Hugh_Caley@affymetrix.com
> 
> --
> "Brain-eating mutants are bad for business" - Battle Angel 
> Batmensch <hcaley@plasmabat.com>
> 
> 
> 
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