用LVM低速写入kvm guest虚拟机的磁盘速度

我的Windows 2008 R2 KVM guest虚拟机有问题。 它向磁盘写入速度极慢： 但是在这台KVM主机上的另一台虚拟机（Windows 10）上，写入速度没问题：

# cat /etc/system-release CentOS Linux release 7.1.1503 (Core) # virsh -V Virsh command line tool of libvirt 1.2.8 See web site at http://libvirt.org/ Compiled with support for: Hypervisors: QEMU/KVM LXC ESX Test Networking: Remote Network Bridging Interface netcf Nwfilter VirtualPort Storage: Dir Disk Filesystem SCSI Multipath iSCSI LVM Gluster Miscellaneous: Daemon Nodedev SELinux Secrets Debug DTrace Readline Modular # qemu-system-x86_64 -version QEMU emulator version 2.0.0, Copyright (c) 2003-2008 Fabrice Bellard 

慢VM XMLconfiguration：

 <domain type='kvm' id='24'> <name>SLOW-VM</name> <uuid>405f55de-ee46-7d1a-4915-a82b617f5706</uuid> <memory unit='KiB'>8388608</memory> <currentMemory unit='KiB'>8388608</currentMemory> <vcpu placement='static'>2</vcpu> <resource> <partition>/machine</partition> </resource> <os> <type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='localtime'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/libexec/qemu-kvm</emulator> <disk type='block' device='disk'> <driver name='qemu' type='raw'/> <source dev='/dev/vg/slow-vm'/> <backingStore/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> <disk type='block' device='floppy'> <driver name='qemu' type='raw'/> <source dev='/dev/vg/slow-vm-2'/> <backingStore/> <target dev='fda' bus='fdc'/> <alias name='fdc0-0-0'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> <controller type='fdc' index='0'> <alias name='fdc0'/> </controller> <controller type='usb' index='0'> <alias name='usb0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/> </controller> <controller type='pci' index='0' model='pci-root'> <alias name='pci.0'/> </controller> <serial type='pty'> <source path='/dev/pts/1'/> <target port='0'/> <alias name='serial0'/> </serial> <console type='pty' tty='/dev/pts/1'> <source path='/dev/pts/1'/> <target type='serial' port='0'/> <alias name='serial0'/> </console> <input type='mouse' bus='ps2'/> <input type='keyboard' bus='ps2'/> <graphics type='vnc' port='5901' autoport='yes' listen='127.0.0.1' keymap='en-us'> <listen type='address' address='127.0.0.1'/> </graphics> <video> <model type='cirrus' vram='16384' heads='1'/> <alias name='video0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </video> <memballoon model='virtio'> <alias name='balloon0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </memballoon> </devices> </domain> 

另一个VM XMLconfiguration：

 <domain type='kvm' id='21'> <name>vm</name> <uuid>e48f03ad-aced-452b-9e85-904ee5be61cb</uuid> <memory unit='KiB'>1048576</memory> <currentMemory unit='KiB'>1048576</currentMemory> <vcpu placement='static'>2</vcpu> <resource> <partition>/machine</partition> </resource> <os> <type arch='x86_64' machine='pc-i440fx-1.5'>hvm</type> <boot dev='cdrom'/> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <cpu mode='custom' match='exact'> <model fallback='allow'>cpu64-rhel6</model> <feature policy='require' name='nx'/> </cpu> <clock offset='localtime'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/bin/qemu-system-x86_64</emulator> <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none'/> <source dev='/dev/vg/vm'/> <backingStore/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <backingStore/> <target dev='hdd' bus='ide'/> <readonly/> <alias name='ide0-1-0'/> <address type='drive' controller='0' bus='1' target='0' unit='0'/> </disk> <controller type='usb' index='0'> <alias name='usb0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/> </controller> <controller type='ide' index='0'> <alias name='ide0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/> </controller> <controller type='pci' index='0' model='pci-root'> <alias name='pci.0'/> </controller> <serial type='pty'> <source path='/dev/pts/4'/> <target port='0'/> <alias name='serial0'/> </serial> <console type='pty' tty='/dev/pts/4'> <source path='/dev/pts/4'/> <target type='serial' port='0'/> <alias name='serial0'/> </console> <input type='tablet' bus='usb'> <alias name='input0'/> </input> <input type='mouse' bus='ps2'/> <input type='keyboard' bus='ps2'/> <graphics type='vnc' port='5903' autoport='yes' listen='127.0.0.1' keymap='en-us'> <listen type='address' address='127.0.0.1'/> </graphics> <video> <model type='cirrus' vram='16384' heads='1'/> <alias name='video0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </video> <memballoon model='virtio'> <alias name='balloon0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </memballoon> </devices> </domain> 

我尝试使用cache ='none'和io ='native' – 没有结果。 我试图在慢速的虚拟机上更改模拟器和机器types – 没有结果。

• QEMU / KVM nic属性
• 删除KVM来宾后留下的文件
• KVM虚拟化下的IPv6路由
• 迁移到其他服务器后，Linux / Proxmox KVM机器将不可靠
• 相同的libvirtconfiguration，一台机器启动，另一台没有

lsblk：

 sdd 8:48 0 931.5G 0 disk |-sdd1 8:49 0 500M 0 part | `-md0 9:0 0 499.7M 0 raid1 /boot `-sdd2 8:50 0 931G 0 part `-md1 9:1 0 1.8T 0 raid10 |-vg-slowvm 253:0 0 180G 0 lvm |-vg-vm 253:13 0 24G 0 lvm 

错在哪里？