[Samba] Transfer speed

[Emmanuel Florac]

Le Mon, 9 Apr 2012 10:17:25 +0200 vous écriviez:

> I'm almost sure than Samba can use almost full gbps speed but how to
> enabled that ? :(

As I mentioned in my previous post, Samba can achieve full Gb speed
easily but not with any client. Basically, Linux, Mac OS X and old
windows (winXP, win2K3) can't achieve nearly as good performance as
win7-64 or win2K8R2 (usually limited to 60-75% of the latter).

Another rule of the thumb I've determined is that you can achieve about
half the raw disk throughput performance with samba. That means that if
you can read-write locally at 120 MB/s, your samba performance will
reach 60 MB/s but not much more. If you want 750 MB/s, you'll need a
disk subsystem able to sustain 1.5GB/s.

Note that NFS sharing performs way, way better than CIFS under both
Linux and Mac OS X. Mostly the same restrictions apply about relative
disk and network performance, but any Unix box can saturate (115-120
MB/s) a Gb link over NFS, both directions, given that your disk
subsystem is about twice as fast as that.

From my experience, using modern hardware jumbo framing makes no
difference for transfers across a limited number of machines, even over
10GigE ethernet (this is not the case for Gb hardware before 2005 and
10GigE hardware before 2010). OTOH proper framing makes a dramatic
difference when using InfiniBand. 

So what does this mean for your setup? If you want to saturate your
gigabit link, you'll have to use either several linux/XP/Mac clients,
or 1 win7 or win2K8 client; you'll need fast enough disks (a single
drive definitely won't do), and of course a fast enough machine -- but
anything 64 bits capable definitely is.

-- 
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Emmanuel Florac     |   Direction technique
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