Hi...

Todays interesting windows question.

What kind of realistic transfer speed should i expect when copying files windows-windows on a gbit lan.

we are trying to troubleshoot intermittant performance issues on our enterprise network and are struggling to get a decent baseline.. the fastest we have managed to get is 390m/bit transfer from two very powerful windows box's with large raid arrays. we get very varied results from various systems and various vlans but never more than 400m/bit. even with switch assisted load balancing and HP network teaming.

we are doing acceptance testing for a SAN/NAS system, and one of the criteria is being able to copy a 5gb file over gb lan in 60 seconds.. theoretically this should be possible.. but in reality is it possible using SMB/CIFS?

What's the REAL speed of 1 Gigabit network connection? - Topic Powered by Eve For Enterprise :confused:

What's the REAL speed of 1 Gigabit network connection? - Topic Powered by Eve For Enterprise :confused:

thanks. will try that netcps app.

issue is we are not talking about consumer hardware here so i would expect maximum efficency from catalyst 6500's and 3750s lol

the network guy now has a theory, but i dont understand a word hes saying :rofl:

Unless you have dedicated links you will never get 100% throughput from ethernet as it has collision detection, back off and retry. eg if two things are sending data down the same bit of wire on the switches, then at least some of the time they are going to try and send data at the same time and it will go wrong.

Realistically you'll struggle to get over 75% of theoretical maximum on a well switched LAN and it can get lower quite easily.

Also don't forget the 8b/10b encoding that is usually used.

Try a dedicated link from each machine to the switch or popping the two in their own separate VLan with no other machines in it. Have the switch enforce this and you should get much closer to 1Gbit then.

Just a few things to look at - make sure you are using network cards on a PCI-X or fast PCI-E bus.

Standard PCI isn't fast enough.

If you have network cards at both ends that support Jumbo frames then that can make a significant difference going to an 8k frame instead of 1.5

What networking kit is it going through and can that definitely do full wire speed transfers?

There are noticable improvements in file transfer speeds using server 2008 machines and vista clients as well.

If it's any help, between 2 reasonably specced HP servers with teamed cards but no switch-assisted load balancing, I copied 0.99GB in about one minute using windows explorer and a UNC path. That's with server 2003. Both servers have fast disks with RAID controllers, but were doing other stuff at the time.

At least the one of these servers will move data a lot faster than that: A backup exec job from one of the above was managing 28M/min (I think- not at work now to check) from one end of the site to another over gigabit ethernet, but that's with a remote agent, not CIFS.

Last time I was at home, I was FTPing across some files onto my "home server" in the attick, using standard GigE and a cheapo £50 8 port GigE switch.

I was hitting about 80 MB/s.

OK, that's using FTP and not samba, but at least it proves that the hardware / drivers / OS are capable of punting that kind of speed across a home-made network.

Most of the issues in maximum throughput come from the collisions so if you only have a few machines these will be less likely that if you have lots of busy machines on a single network switch.

Most of the issues in maximum throughput come from the collisions so if you only have a few machines these will be less likely that if you have lots of busy machines on a single network switch.

Levels of broadcast traffic can have an effect as that's processed by all machines on a VLAN , but unicast traffic between two other machines shouldn't have an affect on your file transfers.

There's a free app called Qcheck which is good for network speed benchmarking:

Download Qcheck, Qcheck 1.3 Download

You have to install it on each endpoint though which is a problem if they aren't both windows devices.

Depending on the availability of cash you could start to look at TOE (TCP/IP offload engines) and 10Gb ethernet.

Depending on the availability of cash you could start to look at TOE (TCP/IP offload engines) and 10Gb ethernet.

We have 10gig+toe on our FAS3140's although its been segmented for NFS datastore and iscsi traffic from our VMware farm.. we have separate 4xgig-e in LACP which will be serving CIFS as the filers will also be our fileservers. my worry is i dont think our network infrastructure is as resiliant and performant as it should be.. especially as we will be relying on it for storage services

Random question, have you tried using something other than CIFS, say NFS or FTP to test throughput. CIFS isn't exactly the fastest out there.

Random question, have you tried using something other than CIFS, say NFS or FTP to test throughput. CIFS isn't exactly the fastest out there.

Yeah, we did the same test but using iscsi got much better thruput then.. although still a few anomalys when going cross-stacks. the network guys think they have found the problem, some legacy ISL thingymajiggys

ISL :confused: what has Etherchannel got to do with it? Or are they referring to another meaning to ISL ?