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Iops » История » Версия 8

Андрей Волков, 2012-05-25 19:30

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h1. IOPS (Input/Output Operations Per Second)
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Отличная подборка для понимания показателя IOPS:
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http://en.wikipedia.org/wiki/IOPS
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Утилита тестирования (gentoo):
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sys-block/fio-2.0.7:0::ekb-info
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IOPS в QEMU-KVM
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http://wiki.qemu.org/Features/VirtioIoeventfd
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DiskIOLimits в QEMU-KVM еще не готов:
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http://wiki.qemu.org/Features/DiskIOLimits
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*Background* 
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When several instances of QEMU are running they can interfere with system performance through excessive disk I/O. Sometimes it is desirable to limit disk I/O in order to keep QEMU from affecting other applications or instances. 
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The availability of disk I/O throttling depends on the underlying storage (image file, LVM, NFS, Ceph). On Linux the cgroups blkio-controller supports I/O throttling on block devices but is a relatively recent feature. More importantly, there is no single mechanism for disk I/O throttling across all underlying storage types and for some types there is no way to throttle at all. 
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The disk I/O limits feature introduces QEMU block layer I/O limits together with command-line and QMP interfaces for configuring limits. This allows I/O limits to be imposed across all underlying storage types using a single interface.
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*IBM view*
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http://www.linux-kvm.org/wiki/images/7/72/2011-forum-keep-a-limit-on-it-io-throttling-in-qemu.pdf