Slow LAN Connection

[colin911]

I have ESXI 4.1 (free version) installed on a dell poweredge 2900.  I am experiencing very slow local network transfer speeds.  For eg, If i transfer a 700 MB ISO to a datastore using the vsphere client, it takes about 10 mins to copy over, whereas if I try to copy the same file from one computer to another on the same local lan, it takes about 20 seconds.

Same kind of thing happens when transferring a file from a physical machine to one of the virtual machines on the esxi server (vmwaretools installed).

Can someone confirm if this is typical behaviour and if it isn't what to look into (other than checking the physical wires).

[a_p_]

There may be different reasons for this behavior. Please double check the network settings (speed/duplex) are the same on the switch port and in ESXi  (usually auto/auto in a 1 GBit network and 100/Full in a 100 MBit network). Another reason could be the caching. ESXi does not do any disk caching and fully relies on the RAID controller. Without BBU (battery backed write cache) which allows for write-back operation, you may see a throughput of 5MB/s and less. With BBU this usually increases to >80MB/s.

Can you please test a VM to VM copy to see how this performs!?

André

[colin911]

making another VM to test out the VM to vm transfer nd will update shortly.

the networks settings off the host shows 100/full.

How do I tell if I have BBU?

[a_p_]

the networks settings off the host shows 100/full.

Actually I expected 1000/Full, since you mentioned the 20 seconds in your first post. However, if it is a 100 MBit connection, make sure the speed and duplex settings are explicitly configured as fixed in the vSwitch as well as the physical switch port. Autonegotiation does not work reliably with 100 MBit networks although displayed.

How do I tell if I have BBU?

If you don't know it, you may need to open the server to see whether the memory and the battery are attached to the RAID controller. There might also be some Dell tools which may be able to show this!? However with a write speed of ~5 MB/sec I'm definitely sure the controller does not have BBU attached.

For a list of Dell controllers which support BBU see http://www.dell.com/content/topics/topic.aspx/global/products/pvaul/topics/en/us/raid_controller?c=u...

André

[colin911]

vm to vm, copying 735MB takes about 1 minute. 

must be that the server does not have a gigabit card. 

[a_p_]

According to the spec sheet it should have a gigabit NIC!? Maybe it's plugged into the wrong switch port or the settings are not correct.

André

[colin911]

YEah, I checked BIOS and there are two nics each gigabit.

Tried adding both nics on the server to auto negotiate.  On each nic, I only got 100mb/s.

I realized however taht when i installed ESXI on the server, I only had cat 5 cable, not cat 6.  Think this triggered something on the install?  I doubt that reinstalling ESXI will have any real effect, but could try it if you think it could do anything.

[a_p_]

There's nothing in the ESXi installation that I'm aware of, that would prevent you from switching to gigabit. Did you check the physical switch port configuration yet. Make sure this isn't configured for 100/Full.

André

[colin911]

the switch automatically switches from 100 to 1000 and displays which speed it is capable of by indicating a different colored light.  I disconnected something that was showing 1000 as a speed, then connected the cable to the ESXI and it showed 100.  Very strange.

Still, even if I had 100mb/s or thereabouts, the speed would be fine.  the real issue is that copying goes at an alarming 5 or so. 

I checked in the BIOS and the PERC 5/i raid adapter and could not find anything about Write Cashing that was configurable.  Have an email out to Dell, maybe they can help here.

[a_p_ · Accepted solution]

Even though you mentioned "other than checking the physical wires" in your first post, did you try another cable? Or did you try to connect another system (capable of 1 Gbit/s) to the end of the cable that's currently plugged into to ESXi host?

Please make sure the vSwitch configuration is set to Automatic for speed and duplex on the ESXi host.

André

[colin911]

Sigh.  I made a third cable, and this time I got the right speed.  I feel a bit dumb.  Thank you so much for your help and support.