[sheepdog] Some thoughts based on my preliminary I/O test

[Hongyi Wang]

I understand this is not a failure. But the problem is big IO which causes "poll timeout" hugely degrades the performance. For my test, I tried to write a 10GB file (bs=4m), which is expected to complete in 30m even in 100M network bandwidth. But I cannot finish it in 2 hours (actually I had to kill the task). That is a bit wield.
 
------------------ Original ------------------
From:  "Liu Yuan"<namei.unix at gmail.com>;
Date:  Thu, May 23, 2013 01:28 PM
To:  "Hongyi Wang"<hongyi at zelin.io>; 
Cc:  "sheepdog"<sheepdog at lists.wpkg.org>; 
Subject:  Re: [sheepdog] Some thoughts based on my preliminary I/O test

 
On 05/23/2013 01:17 PM, Hongyi Wang wrote:
> Update for the last mail:
> In order to reproduce the issue "wait_forward_request(167) poll timeout
> 1", we do our test with 100M switch. We can reproduce the issue every
> time with sequential write on a large file (in our case, 10GB).
>  We notice the number of threads reaches ~70 and the network bandwidth
> is saturated (~90Mbps).
> 

No, this is not a failure. Just the nodes or network are busy. SD will
take care of retry of the requests after poll timeout.

Thanks,
Yuan
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