delayed ack, a perfect improvement which not working well :D

We faced with same issue before use IBM SVC but yesterday EMC VNX has a same issue too !

I don’t understand why such improvement available and for what purpose its needed, i will update when discover it but for today disable it forever 😀

Screen Shot 2013-04-11 at 9.21.31 AM



Posted on 11/04/2013, in iSCSI and tagged , . Bookmark the permalink. 1 Comment.

  1. delayed-ack is to improve network performance. Simply, it sends one ACK for multiple requests instead of sending ACKs or each request.
    If requester’s sending algorithm is not supported by receiver there may be timeouts.( so the delayed ack implementation depends on how storage provider handles delayed ack requests ) ..

    for example, if requester sends half of TCP MSS, then sends another packet, the receiver will not send ACK till it receive full MSS of first request. So the timeout will occur.

    so if the the delayed ack is disabled network performance should decrease..


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