Relativy slow transfer speed in vSphere

[dejan]

Hello

My configuration is: IBM X3850M2 with 4 Six Core CPU, 128 Gb RAM, 3x dual port network Intel Corporation 82571EB Gigabit Ethernet Controller

For testing I created only 2 VM (Server 2008) which are both using the same vSwitch ( witk vmnic1 and vmnic2). Both phyisical networks are connected to 1Gb/s switch.

If I copy large file (database backup file aprox. 4GB) from one phyisical server (also connected via 1Gb/s switch) to one VM Server 2008 I get maximum transfer speed about 20 MB/s.

When I copy large file (database backup file aprox. 4GB) between both Server 2008 (trafic should go only between internal vSwitch) I get maximum transfer speed about 33 MB/s.

Both servers are using new VMXNET3 driver (10Gb/s) and the speed are the same if I use VMXNET2 driver. Network utilization within Server 2008 with VMXNET2 driver is only betwen 20% and the CPU utilizaton is always 100% when I do some kind of copying.

Do not get me wrong, but I expected much more network thruput.

Do you get similar transfer rates or is it something wrong with my implementation?

Thank you for any kind of help

[AnatolyVilchins]

What sort of storage is there within the server?

Starwind Software Developer

www.starwindsoftware.com

[AntonVZhbankov]

When you copy file process goes this way:

1. read block from disk

2. send block through network

3. save block to disk

So you're testing disk subsystem more then network. You want to test network - find some pure network benchmark that does not involve disks.

FYI I've got average network speed about 85 MB/s myself in one case on 4.0 beta.

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MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[AnatolyVilchins]

Somethings wrong here, have you check that your MAC addresses of the adapters are unique?

Starwind Software Developer

www.starwindsoftware.com

[AntonVZhbankov]

Anatoly, looks like you replied to wrong message

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MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[dejan]

Thank you both for kind and quick replay.

I am aware of this, but I gave VM to VM copy just for example, that copying from phyisical server to VM server is a little bit slow (on 1Gb/s network only aprox 20MB/s). I would say, that the dropdown should be around 10 or even 20% compared to phyisical to phyisical copy process which I get around 65 to 70 MB/s.

I realize, that the "built in" SAS disk are not the best answer, but for testing perposal, that should be good enogh. Right now I will also check cabeling and I will let you know.

Thank you for now

[AntonVZhbankov]

Did you convert VMDK to eagerzeroedthick before test?

---

MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[Texiwill]

Hello,

Please explain exactly how you are copying the data. I.e. over CIFS shares, SCP, FTP, etc. The protocol used may actually make a difference. Have you tried copying to and from memory instead of from disk to disk? You may have Disk IO issues instead of Network IO issues.

You may wish to use 'netperf' or 'iometer' (network targets tab) instead of something like a copy, as it will test purely the network and not much else.

Best regards,
Edward L. Haletky VMware Communities User Moderator, VMware vExpert 2009

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