I maintain two FTP servers which running on Windows Server 2008 R2 and Xlight FTP Server. Each server has 1Gbit bandwidth to our company's network backbone.

Recently, FTP Service is more unstable because higher load than before. I want to add one more server to resolve the problem while I do not have confident to maintain three servers like that.

And I can't find a good way to distribute file access load to three servers equally. Now I use ftp logs to do that work by manually moving files between two servers according their access rates.

My servers serve big files which more than 100MB like media files. I find a distributed FTP server called DrFTPd which based on Java. After several days I set it up but have many problems.

Do I need a distributed file server solution to solve my problem? If I need, which one will be better?


  • Do the servers have the HD capacity to mirror the content on all three servers? Why are you using Xlight when Server 2008R2 comes with IIS FTP 7.5? What do you mean by "load" exactly? – Chris S Dec 8 '11 at 3:15
  • Do not have a content mirror in my stack. Using Xlight because of we purchased its license. I tried IIS 7.5 FTP and Gene6 FTP before and I believe change server softwares among regular ftp server softwares won't solve my problem. Two servers' peak bandwidth usage could more than 1600Mbps. I think we should add one more server, however,I can not afford the maintainable pressure – Alex Chen Dec 8 '11 at 3:51
  • So you do or do not have space to mirror the content? Sunk costs do not mean you have to use the software, which is very cheap anyway. IIS can take advantage of NLB, which is why I ask. I have an old server in my basement that can do more than 1600Mbps easily, what relevance is that? Similarly you haven't justified adding another server so I do not see how that is relevant. If you're stuck on Xlight you could consider other load balancing solutions, but you're adding additional (arguable unnecessary) complexity. – Chris S Dec 8 '11 at 3:56
  • Ooops, May be I misunderstand your before, I have never tried NLB with IIS FTP before, apologize. I'm afraid I do not have enough spaces to do 1:1 mirroring. My FTP servers connect to IBM DS3212 with 12 2TB SATA disks (two RAID 6 arrays). – Alex Chen Dec 8 '11 at 4:10

You should consider using the Network Load Balancer role/service and DFS-R to maintain a mirror of the FTP structure on all cluster nodes. This really shouldn't be very complicated to setup.

If the NICs are saturated you should be able to somewhat easily add more NICs and Team them to get higher aggregate throughput without adding another server. A 2 or 3 node cluster on modern hardware should easily be able to saturate the disk subsystem in a typical server.

If the disk subsystem is saturated there are higher capacity caching solutions you can add to the servers. You could also expand the disk subsystem, adding spindles/HBAs/connectivity as necessary.

A modern server specifically build for the task should be able to crank 20 to 50+ Gbps out over FTP.

  • That said, you mention that you're distributing media content. Perhaps FTP isn't the best protocol to use. FTP has many security concerns (to put it lightly). RTSP, especially using some form of multicast might be a better solution, but it really depends on your environment and requirements. – Chris S Dec 8 '11 at 3:27
  • Thanks Chris. I just serve media "files" and do not serve streaming so we choose FTP. Currently, My two servers do not have the same file structure, could I use the solution you mentioned? – Alex Chen Dec 8 '11 at 3:56

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