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I'm trying to upload a few Debian ISOs to my ESXi 5 datastore but it's really slow. Far slower than downloading them from the web was in the first place. I've tried both via the GUI uploader and copying via SCP & SFTP.

Am I missing a trick?

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It depends on the bandwidth available. What's your expected upload speed to your ESX box and what are you getting? – Ladadadada Oct 26 '12 at 8:26
The server has dual gigabit ports into a gigabit switch. The workstation only has a 100mb socket, so there's an obvious bottleneck there. But I'd still expect to see transfer speeds of around 10mbps. Instead I'm getting around 50kbps. – Simmo Oct 26 '12 at 8:52
up vote 4 down vote accepted

Datastore transfers can be viscously slow, however make sure that your underlying network is solid before trying anything too specialized. Check drivers, NICs, cables, switches, routers, and etc. Perform a general shakedown on the network to see if any errors are thrown and if obvious bottlenecks are in existence.

Once you've proven that the network's parts are equal to the sum, then consider some little tricks that the VMware community has been using to speed up datastore transfers. Those tricks include:

  • Veeam FastSCP
  • HTTP Transfers (is supported by VMware, or at least it was at one point)
  • Install an FTP daemon on your ESXi host. Did I just say that? No, wasn't me. <_<
  • VMware Converter Standalone was able to help out at one point.
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I did some digging around and apparently I did have a 1gig card in the workstation. For some reason it had auto-detected to 100. When I set it manually to 1gig, full duplex, the performance is much improved. Uploading a 4.5gb iso took less than 10 minutes. Thanks, Simmo – Simmo Oct 26 '12 at 10:03

generally when the transfers are verrryyy slow its because the NIC settings have been messed up. When I upgraded from ESXi5.1 to 5.5 the NIC ended up as 10Mbps half duplex for some reason.

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