Tag Archives: nfs

Latency impact on NFS link

Interesting document about NFS and iSCSI performance over latency, even if it is new a new document, the study made is really complete and interesting. As I was mostly interested on the performance of NFS over a WAN access with a high latency, I would summarize it by concluding that the maximum performance of file transfer over NFS is not so far the following list:

Time to read 128MB / latency (read is the worst case)

  • 10 ms latency requires 200s, max bandwidth is about 640KB/s – 5.12Mbits/s
  • 20 ms latency requires 300s, max bandwidth is about 427KB/s – 3.41Mbits/s
  • 30 ms latency requires 500s, max bandwidth is about 256KB/s – 2.05Mbits/s
  • 50 ms latency requires 800s, max bandwisth is about 160KB/s – 1.28Mbits/s
  • 90 ms latency requires 1600s, max bandwidth is about 80KB/s – 640Kbits/s

For details and much more information, take a look to the source document : http://lass.cs.umass.edu/papers/pdf/FAST04.pdf

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