Jurre Posted October 8, 2018 Share Posted October 8, 2018 (edited) I'm getting really terrible write speeds inside my windows VM. The read speeds are great 1.8GB/s, but the writes don't get above 50kb/s. If I run the following command on unraid I get a more reasonable write speed. Quote dd if=/dev/zero of=/mnt/cache/test.dd count=8192000 bs=64k count=8k 8192+0 records in 8192+0 records out 536870912 bytes (537 MB, 512 MiB) copied, 0.266534 s, 2.0 GB/s Quote root@R720:~# dd if=/dev/zero of=/mnt/cache/test.dd count=8192000 bs=64k count=80k 81920+0 records in 81920+0 records out 5368709120 bytes (5.4 GB, 5.0 GiB) copied, 5.09313 s, 1.1 GB/s But In the windows VM, when I run CrystalDiskMark it will even timeout the RDP session, and freeze the VNC session, until the test is done. All the read speeds are 500MB/s or higher but all the write speeds are either 0MB/s or 1MB/s. This is my config: <?xml version='1.0' encoding='UTF-8'?> <domain type='kvm' id='1'> <name>Windows 10</name> <uuid>91b82e52-7a3d-d320-f943-ff2320c3395b</uuid> <metadata> <vmtemplate xmlns="unraid" name="Windows 10" icon="windows.png" os="windows10"/> </metadata> <memory unit='KiB'>33030144</memory> <currentMemory unit='KiB'>33030144</currentMemory> <memoryBacking> <nosharepages/> </memoryBacking> <vcpu placement='static'>12</vcpu> <cputune> <vcpupin vcpu='0' cpuset='6'/> <vcpupin vcpu='1' cpuset='18'/> <vcpupin vcpu='2' cpuset='7'/> <vcpupin vcpu='3' cpuset='19'/> <vcpupin vcpu='4' cpuset='8'/> <vcpupin vcpu='5' cpuset='20'/> <vcpupin vcpu='6' cpuset='9'/> <vcpupin vcpu='7' cpuset='21'/> <vcpupin vcpu='8' cpuset='10'/> <vcpupin vcpu='9' cpuset='22'/> <vcpupin vcpu='10' cpuset='11'/> <vcpupin vcpu='11' cpuset='23'/> </cputune> <resource> <partition>/machine</partition> </resource> <os> <type arch='x86_64' machine='pc-i440fx-3.0'>hvm</type> <loader readonly='yes' type='pflash'>/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi.fd</loader> <nvram>/etc/libvirt/qemu/nvram/91b82e52-7a3d-d320-f943-ff2320c3395b_VARS-pure-efi.fd</nvram> </os> <features> <acpi/> <apic/> <hyperv> <relaxed state='on'/> <vapic state='on'/> <spinlocks state='on' retries='8191'/> <vendor_id state='on' value='none'/> </hyperv> </features> <cpu mode='host-passthrough' check='none'> <topology sockets='1' cores='6' threads='2'/> </cpu> <clock offset='localtime'> <timer name='hypervclock' present='yes'/> <timer name='hpet' present='no'/> </clock> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/local/sbin/qemu</emulator> <disk type='file' device='disk'> <driver name='qemu' type='raw' cache='writeback'/> <source file='/mnt/user/domains/Windows 10/vdisk1.img'/> <backingStore/> <target dev='hdc' bus='virtio'/> <boot order='1'/> <alias name='virtio-disk2'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </disk> <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <source file='/mnt/user/isos/Windows 10.iso'/> <backingStore/> <target dev='hda' bus='ide'/> <readonly/> <boot order='2'/> <alias name='ide0-0-0'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <source file='/mnt/user/isos/virtio-win-0.1.141.iso'/> <backingStore/> <target dev='hdb' bus='ide'/> <readonly/> <alias name='ide0-0-1'/> <address type='drive' controller='0' bus='0' target='0' unit='1'/> </disk> <controller type='usb' index='0' model='ich9-ehci1'> <alias name='usb'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x7'/> </controller> <controller type='usb' index='0' model='ich9-uhci1'> <alias name='usb'/> <master startport='0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0' multifunction='on'/> </controller> <controller type='usb' index='0' model='ich9-uhci2'> <alias name='usb'/> <master startport='2'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x1'/> </controller> <controller type='usb' index='0' model='ich9-uhci3'> <alias name='usb'/> <master startport='4'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x2'/> </controller> <controller type='pci' index='0' model='pci-root'> <alias name='pci.0'/> </controller> <controller type='ide' index='0'> <alias name='ide'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/> </controller> <controller type='sata' index='0'> <alias name='sata0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </controller> <controller type='virtio-serial' index='0'> <alias name='virtio-serial0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </controller> <interface type='bridge'> <mac address='52:54:00:8d:1c:c4'/> <source bridge='br0'/> <target dev='vnet0'/> <model type='virtio'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> <serial type='pty'> <source path='/dev/pts/0'/> <target type='isa-serial' port='0'> <model name='isa-serial'/> </target> <alias name='serial0'/> </serial> <console type='pty' tty='/dev/pts/0'> <source path='/dev/pts/0'/> <target type='serial' port='0'/> <alias name='serial0'/> </console> <channel type='unix'> <source mode='bind' path='/var/lib/libvirt/qemu/channel/target/domain-1-Windows 10/org.qemu.guest_agent.0'/> <target type='virtio' name='org.qemu.guest_agent.0' state='disconnected'/> <alias name='channel0'/> <address type='virtio-serial' controller='0' bus='0' port='1'/> </channel> <input type='tablet' bus='usb'> <alias name='input0'/> <address type='usb' bus='0' port='1'/> </input> <input type='mouse' bus='ps2'> <alias name='input1'/> </input> <input type='keyboard' bus='ps2'> <alias name='input2'/> </input> <graphics type='vnc' port='5900' autoport='yes' websocket='5700' listen='0.0.0.0' keymap='en-us'> <listen type='address' address='0.0.0.0'/> </graphics> <video> <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/> <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='0x08' function='0x0'/> </memballoon> </devices> <seclabel type='dynamic' model='dac' relabel='yes'> <label>+0:+100</label> <imagelabel>+0:+100</imagelabel> </seclabel> </domain> Does anyone have an idea, why my writes speeds inside the VM are so terrible? Edited October 8, 2018 by Jurre Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.