DocumentCode :
3182415
Title :
Tuning Open-iSCSI for Operation over WAN Links
Author :
Zhang, Y. ; MacGregor, M.H.
Author_Institution :
Dept. of Comput. Sci., Univ. of Alberta, Edmonton, AB, Canada
fYear :
2011
fDate :
2-5 May 2011
Firstpage :
85
Lastpage :
92
Abstract :
The relocation of live, running virtual machines from one physical host to another is a new and very desirable function because it provides a variety of features, including resilience to failures and flexibility of location. The data transfers required for live migration are supported in several commercial products by a protocol called iSCSI (Internet SCSI), which runs on top of TCP. We thoroughly tested the performance of a common open source component, the Open-iSCSI initiator, and found a drastic throughput degradation on 100 Mbps networks where the round trip time was more than about 40 ms. We localized the problem to the TCP send buffer size and tested two methods of setting the TCP send buffer size appropriately. Based on our results, we propose a performance tuning scheme that enables users of Open-iSCSI to achieve significant throughput gains. Our scheme results in a dramatic throughput jump from 14 Mbps to 70 Mbps on a 100 Mbps link with an RTT of 100 ms. We also modified one of the data structures internal to Open-iSCSI to handle multiple memory pages in a single scatter/gather list entry. This modification resulted in an additional 20% throughput increase on a 100 Mbps link with an RTT of 200 ms.
Keywords :
Internet; data structures; transport protocols; virtual machines; wide area networks; TCP; WAN link; bit rate 100 Mbit/s; bit rate 14 Mbit/s; bit rate 70 Mbit/s; data structure; open source component; open-Internet SCSI tuning; performance tuning scheme; protocol; virtual machine; Delay; Kernel; Linux; Protocols; Throughput; Virtual machining; Wide area networks; iSCSI; throughput;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Communication Networks and Services Research Conference (CNSR), 2011 Ninth Annual
Conference_Location :
Ottawa, ON
Print_ISBN :
978-1-4577-0040-8
Electronic_ISBN :
978-0-7695-4393-2
Type :
conf
DOI :
10.1109/CNSR.2011.21
Filename :
5771196
Link To Document :
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