I think a lot of dedicated server providers can let you to setup vlan.
Actually, I got 1 Windows server and 3 Linux servers, I want to map a network drive from linux server to win server, so that I can see the linux content on win server. And all my servers got 1 NIC only, so is vlan a good option?
My servers are running at 10Mbps port, if I transfer files through vlan between servers, can I have the 100Mbps speed?
Vlan is basically for security it puts you in a virtiual private LAN alot of datacenters do this to keep other servers on the same switch from seeing any of your broadcast traffic. also on vlans each server has its own gateway IP and subnet
now you could ask your host if they could put your servers in the same vlan with diffrent IPs or ask them to install 2nd NIC's and cross cable the servers for a small fee then you could also possible get the full 100Mbit between servers.
If your on a 10Mbit port per server then the max you can transfer between servers even in the same datacenter is 10Mbit or about 1.2 MegaBytes per second