Tag Archives: latency

Compared performance of different file transfer protocols over latency

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Internet is providing more and more bandwidth to transfer files and files are bigger and bigger. One thing is not changing, it is latency as distance still the same over the time. When a protocol requires acknowledgment between blocks of transfer this latency is limiting the throughput like explained in this post.

The throughput is really different depending on the protocol in use to transfer the file. As I did not found something giving a lot of data to compare the existing protocol, i’ll try to get figures myself and detail here.

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Oracle DB performance over low latency networks

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Here is an interesting article on the impact of the latency on some usual Oracle SQL statement over Local, LAN and WAN networks.

http://markbairden.blogspot.fr/2012/03/database-performance-measuring-effects.html

Wan latency uses is 12ms which is small for this type of connection. Impact is huge with a factor of 10. To be taken into account in your designs !

Thank you Mark for this article !

Latency impact on NFS link

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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