Centos 6下配置KVM使用virtio-scsi

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操作环境

Centos 6.5 x86_64

qemu-img-0.12.1.2-2.415.el6.3ceph.x86_64

qemu-kvm-0.12.1.2-2.415.el6.3ceph.x86_64

libvirt-python-0.10.2-29.el6_5.12.x86_64

libvirt-0.10.2-29.el6_5.12.x86_64

libvirt-client-0.10.2-29.el6_5.12.x86_64

操作说明

kvm对于块设备默认使用virtio-blk模板，后来提出virtio-scsi用来取代virtio-blk，可以提高性能以及可扩张性，在virtio-blk模块下，硬盘设备显示字符为/dev/vd*，在virtio-scsi木块下，硬盘设备显示为/dev/sd*，下面为操作步骤。

创建scsi-controller

<controller type='scsi' model='virtio-scsi'/>

将scsi-controller设备添加在kvm guest中，此时kvm guset应为关闭状态

virsh attach-device --config demo-linux scsi-controller.xml

创建硬盘设备

#fallocate -l 20480M /var/lib/libvirt/images/sda.img

创建硬盘sda的xml文件sda.xml

<disk type='file' device='disk'>        <device name='qemu' type='raw' cache='none'/>        <source file='/var/lib/libvirt/images/sdc.img'/>        <target dev='sdc'/></disk>

添加硬盘设备到kvm guest中

#virsh attach-device --config demo-linux sda.xml

启动kvm guest ，查看硬盘设备

[root@demo-ceph ~]# fdisk -l /dev/sdaDisk /dev/sda: 21.5 GB, 21474836480 bytes64 heads, 32 sectors/track, 20480 cylindersUnits = cylinders of 2048 * 512 = 1048576 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0x00000000

查看现有scsi设备

[root@demo-ceph ~]# lsscsi [1:0:0:0]    cd/dvd  QEMU     QEMU DVD-ROM     0.12  -       [2:0:0:1]    disk    QEMU     QEMU HARDDISK    0.12  -

查看pci设备，在最后面可以找到基于virtio-scsi的scsi controller。

[root@demo-ceph ~]# lspci00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02)00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]00:01.2 USB controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01)00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)00:02.0 VGA compatible controller: Cirrus Logic GD 544600:03.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 20)00:04.0 SCSI storage controller: Red Hat, Inc Virtio block device00:05.0 SCSI storage controller: Red Hat, Inc Virtio block device00:06.0 RAM memory: Red Hat, Inc Virtio memory balloon00:07.0 SCSI storage controller: Red Hat, Inc Virtio block device00:08.0 SCSI storage controller: Red Hat, Inc Virtio SCSI

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