Mailinglist Archive: opensuse (5130 mails)

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Re: [SLE] Which transport is the faster?
  • From: Maarten Hilgenga <M.L.Hilgenga@xxxxxx>
  • Date: Fri, 12 May 2006 11:04:56 +0200
  • Message-id: <44644FB8.5090901@xxxxxx>
Anders Norrbring wrote:
Greg Freemyer skrev:
On 5/11/06, Anders Norrbring <lists@xxxxxxxxxxxx> wrote:
Which transport method is generally faster than the other between two
Linux boxes?

NFS or software based iSCSI?


I don't know, but you do realize that the 2 are very different, right?

iSCSI exports a dedicated block device (ie. a disk drive, partition,
etc.). Even the iSCSI server should not access the dedicated device
except at the request of a client.

NFS exports a non-dedicated FS, so it has the potential to be more
flexible and allows multiple clients as well as the server itself to
access the same FS.

I think the eventual use case for iSCSI is to build a server with tons
of reconfigurable disk space, then export pieces of that to a set of
iSCSI clients. Very much like Fibre-Channel. Then if server 1 ends
up needing less space and server 2 needs more you can shift your
resources around.

I don't think the above reallocation capability works in generic linux
yet. It would require LVM (or something like it) to be running on the
server below the iSCSI driver.

Another use case for iSCSI that I believe does work today in Linux is
to use iSCSI as the shared stored in a clustered FS like GFS. Be
warned the GFS runs slower than local disk, so really have to need the
cluster FS feature to justify the performance drop.


Thanks Greg,
I know all that.. :) What I'm up to is to build a NAS with as high throughput as possible, and the differencies between the two ways aren't significant in this case, it should just be storage... It doesn't matter if it's a mounted directory (NFS) or a mounted device (iSCSI).


This might be a good read:



University of Groningen
Department of Applied Physics
Nijenborgh 4, 9747 AG Groningen
The Netherlands
tel: +31-50-3638045
fax: +31-50-3634886
email : m.l.hilgenga@xxxxxx

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