Advanced Resource Sharingin the Cloud

Eiji KawaiNICT

Cloud computing

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Sharing everything

Bound tohosts

Virtualized

CPU

Memory

Storage

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Three approachesto large scale memory sharing

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Virtualization of virtual memory• Our approach: mount remote memory as swap device

– Physical memory is already virtualized in OS (VM: virtual memory)– Pro: High performance– Con: (straightforward) implementation in kernel VM layer is highly

difficult

Physical MemoryPhysical Memory

VMVM

ProcessProcess

Physical MemoryPhysical Memory

TCP/IPTCP/IP

TCP/IPTCP/IP VMVM

Physical memoryPhysical memory

VM/FSVM/FS

ProcessProcess

ATA/SCSIATA/SCSI

Swap deviceSwap device

Normal system Extended system2009/12/16 5AFICT2009

Leveraging LVM and iSCSI• System configuration is highly flexible, thanks to modern

LVM (logical volume management) mechanism– Dynamic attachment/detachment of remote memory linked to

the memory usage• iSCSI performance in high latency networks is well-studied

– Distributed cloud environment

Physical MemoryPhysical Memory

VM/FSVM/FS

ProcessProcess

TCP/IPTCP/IP

iSCSIiSCSI

LVMLVM

Physical MemoryPhysical Memory

VM/FSVM/FS

TCP/IPTCP/IP

iSCSIiSCSI

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Performance: sequential access (read)

2.3X-3.3X faster

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Performance: random access (read)

17.0x-28.0x faster

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Summary

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Thank you

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