Having some weirdness with a new guest server. I'll try to summarize what I've seen and what we've tried to do to fix it.
Issue:
We set up the new server as a minor file server using Windows 2012. Should be fairly low utilization. Installation went well, but when we tried to move the files to it from another physical machine, the small files copied very well, but larger files timed out (or took hours). Using performance monitoring, I found that data transfers for large files would "bounce"...specifically, they would transfer at about 500Mbps for the first 2-3gb, then drop to zero. Every 15-20 seconds, they would burst back up to 200Mbps, then fall back to zero immediately. After about another 2gb of transfer, it would time out. Files smaller than 5gb would eventually make it to the guest, but anything larger did not. Anything smaller than 2gb got there VERY fast.
Specs:
- Host is ESXi 5.1 with the newest update.
- Single host machine with 2-core CPU. The guest has 2-cores assigned to it
- Dual Intel gigabit NIC, currently set to use one as active and one as standby
- Host has 24gb memory and this guest has 4gb. It is not overcommitted.
- There are only three guests on this host. I turned the others off to ensure they were not conflicting in some way.
- 2012 guest has a vmxnet3 NIC.
Tests I've done:
- Given that the data is coming from a physical machine to virtual, I tried reversing direction, but had the same issues. I copied physical-to-physical with no issue, isolating my problem to the ESXi box and/or guests.
- Checked host datastore, cpu, memory, and networking performance. None are high. The host networking shows the same high up and downs.
- I tested data transfer between guests on different datastores. Same issue occurs (600-800Mbps for a little while, then bouncing). However, if I transfer to or from another guest without touching the 2012 box, the speeds are steady.
- Per random recommendations on the web, I've tried removing Remote Differential Compression, RSS, TOS (and other offloading). No change at all. Also, Windows yells at me for having them disabled. I've re-enabled them all with no change.
Before I go completely crazy, I wanted to ask the community if they had any ideas.