[CentOS] connection speeds between nodes

Mon Mar 7 12:13:51 UTC 2011
Rafa Griman <rafagriman at gmail.com>

Hi :)

On Mon, Mar 7, 2011 at 12:12 PM, wessel van der aart
<wessel at postoffice.nl> wrote:
> Hi All,
> I've been asked to setup a 3d renderfarm at our office , at the start it
> will contain about 8 nodes but it should be build at growth. now the
> setup i had in mind is as following:
> All the data is already stored on a StorNext SAN filesystem (quantum )
> this should be mounted on a centos server trough fiber optics  , which
> in its turn shares the FS over NFS to all the rendernodes (also centos).

>From what I can read, you have 1 NFS server only and a separate
StoreNext MDC. Is this correct?

> Now we've estimated that the average file send to each node will be
> about 90MB , so that's what i like the average connection to be, i know
> that gigabit ethernet should be able to that (testing with iperf
> confirms that) but testing the speed to already existing nfs shares
> gives me a 55MB max. as i'm not familiar with network shares performance
> tweaking is was wondering if anybody here did and could give me some
> info on this?
> Also i thought on giving all the nodes 2x1Gb-eth ports and putting those
> in a BOND, will do this any good or do i have to take a look a the nfs
> server side first?

Things to check would be:
     - Hardware:
          * RAM and cores on the NFS server
          * # of GigE & FC ports
          * PCI technology you're using: PCIe, PCI-X, ...
          * PCI lanes & bandwidth you're using up
          * if you are sharing PCI buses between different PCI boards
(FC and GigE): you should NEVER do this. If you have to share a PCI
bus, share it between two PCI devices which are the same. That is you
can share a PCI bus between 2 GigE cards or between 2 FC cards, but
never mix the devices.
          * cabling
          * switch configuration
          * RAID configuration
          * cache configuration on the RAID controller. Cache
mirroring gives you more protection, but less performance.

     - software:
          * check the NFS config. There are some interesting tips if
you google around.