I'm using KVM on Debian 10 as host and for now two guests that are Debian 10 as well. The guests are "stuttering" frequently, what I mean by that is that like at least several times an hour a guest becomes unresponsive for like 10 seconds. If I have an SSH session open and I'm typing I can do nothing until the guest spontaneously "unfreezes". It seems like what I typed just before "freeze" is still buffered, because once the guest unfreezes, it all appears in command line.
The host box does not suffer anything like that.
The host is part of active/passive cluster with following configuration:
- Two disks are working in RAID-1 setup, two partitions form
/dev/md0
for root fs, two bigger partions are joined into/dev/md1
for guest data. /dev/md1
is used for DRBD device between two cluster hosts. Protocol C for synchronous writes is used between the hosts.- LVM is stacked on top of DRBD device. Guests use raw LVM volumes for disks.
- The second host is NOT present, it's not production yet.
I did not really change anything in either KVM host or guest settings if I remember correctly, just used the defaults. Anyway, this is the configuration I have:
Guest domain XML definition:
% cat bind.xml
<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
virsh edit bind
or other application using the libvirt API.
-->
<domain type='kvm'>
<name>bind</name>
<uuid>6fc751ea-2ce0-4e69-b098-48b8ea0fc78a</uuid>
<metadata>
<libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0">
<libosinfo:os id="http://debian.org/debian/10"/>
</libosinfo:libosinfo>
</metadata>
<memory unit='KiB'>1048576</memory>
<currentMemory unit='KiB'>1048576</currentMemory>
<vcpu placement='static'>1</vcpu>
<os>
<type arch='x86_64' machine='pc-q35-3.1'>hvm</type>
<bootmenu enable='yes'/>
</os>
<features>
<acpi/>
<apic/>
<vmport state='off'/>
</features>
<cpu mode='host-model' check='partial'>
<model fallback='allow'/>
</cpu>
<clock offset='utc'>
<timer name='rtc' tickpolicy='catchup'/>
<timer name='pit' tickpolicy='delay'/>
<timer name='hpet' present='no'/>
</clock>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<pm>
<suspend-to-mem enabled='no'/>
<suspend-to-disk enabled='no'/>
</pm>
<devices>
<emulator>/usr/bin/qemu-system-x86_64</emulator>
<disk type='block' device='disk'>
<driver name='qemu' type='raw' cache='none' io='native'/>
<source dev='/dev/vgr0/bind'/>
<target dev='vda' bus='virtio'/>
<boot order='2'/>
<address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<target dev='sda' bus='sata'/>
<readonly/>
<boot order='1'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
<controller type='usb' index='0' model='qemu-xhci' ports='15'>
<address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/>
</controller>
<controller type='sata' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
</controller>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='1' port='0x10'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0' multifunction='on'/>
</controller>
<controller type='pci' index='2' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='2' port='0x11'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x1'/>
</controller>
<controller type='pci' index='3' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='3' port='0x12'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x2'/>
</controller>
<controller type='pci' index='4' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='4' port='0x13'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x3'/>
</controller>
<controller type='pci' index='5' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='5' port='0x14'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x4'/>
</controller>
<controller type='pci' index='6' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='6' port='0x15'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x5'/>
</controller>
<controller type='pci' index='7' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='7' port='0x16'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x6'/>
</controller>
<controller type='virtio-serial' index='0'>
<address type='pci' domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
</controller>
<interface type='bridge'>
<mac address='52:54:00:da:43:59'/>
<source bridge='br0'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</interface>
<interface type='bridge'>
<mac address='52:54:00:25:ea:03'/>
<source bridge='br1'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
</interface>
<serial type='pty'>
<target type='isa-serial' port='0'>
<model name='isa-serial'/>
</target>
</serial>
<console type='pty'>
<target type='serial' port='0'/>
</console>
<channel type='unix'>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>
</channel>
<channel type='spicevmc'>
<target type='virtio' name='com.redhat.spice.0'/>
<address type='virtio-serial' controller='0' bus='0' port='2'/>
</channel>
<input type='tablet' bus='usb'>
<address type='usb' bus='0' port='1'/>
</input>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<graphics type='spice' autoport='yes'>
<listen type='address'/>
<image compression='off'/>
</graphics>
<sound model='ich9'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1b' function='0x0'/>
</sound>
<video>
<model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
</video>
<redirdev bus='usb' type='spicevmc'>
<address type='usb' bus='0' port='2'/>
</redirdev>
<redirdev bus='usb' type='spicevmc'>
<address type='usb' bus='0' port='3'/>
</redirdev>
<memballoon model='virtio'>
<address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'/>
</memballoon>
<rng model='virtio'>
<backend model='random'>/dev/urandom</backend>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/>
</rng>
</devices>
</domain>
QEMU settings:
% virsh -c qemu:///system capabilities
<capabilities>
<host>
<uuid>53f34900-9b09-11e2-98e4-6c3be51bf934</uuid>
<cpu>
<arch>x86_64</arch>
<model>IvyBridge-IBRS</model>
<vendor>Intel</vendor>
<microcode version='33'/>
<topology sockets='1' cores='4' threads='1'/>
<feature name='ds'/>
<feature name='acpi'/>
<feature name='ss'/>
<feature name='ht'/>
<feature name='tm'/>
<feature name='pbe'/>
<feature name='dtes64'/>
<feature name='monitor'/>
<feature name='ds_cpl'/>
<feature name='vmx'/>
<feature name='smx'/>
<feature name='est'/>
<feature name='tm2'/>
<feature name='xtpr'/>
<feature name='pdcm'/>
<feature name='pcid'/>
<feature name='osxsave'/>
<feature name='arat'/>
<feature name='md-clear'/>
<feature name='stibp'/>
<feature name='ssbd'/>
<feature name='xsaveopt'/>
<feature name='invtsc'/>
<pages unit='KiB' size='4'/>
<pages unit='KiB' size='2048'/>
</cpu>
<power_management>
<suspend_mem/>
</power_management>
<iommu support='no'/>
<migration_features>
<live/>
<uri_transports>
<uri_transport>tcp</uri_transport>
<uri_transport>rdma</uri_transport>
</uri_transports>
</migration_features>
<topology>
<cells num='1'>
<cell id='0'>
<memory unit='KiB'>16298904</memory>
<pages unit='KiB' size='4'>4074726</pages>
<pages unit='KiB' size='2048'>0</pages>
<distances>
<sibling id='0' value='10'/>
</distances>
<cpus num='4'>
<cpu id='0' socket_id='0' core_id='0' siblings='0'/>
<cpu id='1' socket_id='0' core_id='1' siblings='1'/>
<cpu id='2' socket_id='0' core_id='2' siblings='2'/>
<cpu id='3' socket_id='0' core_id='3' siblings='3'/>
</cpus>
</cell>
</cells>
</topology>
<cache>
<bank id='0' level='3' type='both' size='6' unit='MiB' cpus='0-3'/>
</cache>
<secmodel>
<model>apparmor</model>
<doi>0</doi>
</secmodel>
<secmodel>
<model>dac</model>
<doi>0</doi>
<baselabel type='kvm'>+64055:+64055</baselabel>
<baselabel type='qemu'>+64055:+64055</baselabel>
</secmodel>
</host>
<guest>
<os_type>hvm</os_type>
<arch name='i686'>
<wordsize>32</wordsize>
<emulator>/usr/bin/qemu-system-i386</emulator>
<machine maxCpus='255'>pc-i440fx-3.1</machine>
<machine canonical='pc-i440fx-3.1' maxCpus='255'>pc</machine>
<machine maxCpus='1'>isapc</machine>
<machine maxCpus='255'>pc-1.1</machine>
<machine maxCpus='255'>pc-1.2</machine>
<machine maxCpus='255'>pc-1.3</machine>
<machine maxCpus='255'>pc-i440fx-2.8</machine>
<machine maxCpus='255'>pc-1.0</machine>
<machine maxCpus='255'>pc-i440fx-2.9</machine>
<machine maxCpus='255'>pc-i440fx-2.6</machine>
<machine maxCpus='255'>pc-i440fx-2.7</machine>
<machine maxCpus='128'>xenfv</machine>
<machine maxCpus='255'>pc-i440fx-2.3</machine>
<machine maxCpus='255'>pc-i440fx-2.4</machine>
<machine maxCpus='255'>pc-i440fx-2.5</machine>
<machine maxCpus='255'>pc-i440fx-2.1</machine>
<machine maxCpus='255'>pc-i440fx-2.2</machine>
<machine maxCpus='288'>pc-q35-3.1</machine>
<machine canonical='pc-q35-3.1' maxCpus='288'>q35</machine>
<machine maxCpus='255'>pc-i440fx-2.0</machine>
<machine maxCpus='288'>pc-q35-2.11</machine>
<machine maxCpus='288'>pc-q35-2.12</machine>
<machine maxCpus='288'>pc-q35-3.0</machine>
<machine maxCpus='1'>xenpv</machine>
<machine maxCpus='288'>pc-q35-2.10</machine>
<machine maxCpus='255'>pc-i440fx-1.7</machine>
<machine maxCpus='288'>pc-q35-2.9</machine>
<machine maxCpus='255'>pc-0.15</machine>
<machine maxCpus='255'>pc-i440fx-1.5</machine>
<machine maxCpus='255'>pc-q35-2.7</machine>
<machine maxCpus='255'>pc-i440fx-1.6</machine>
<machine maxCpus='255'>pc-i440fx-2.11</machine>
<machine maxCpus='288'>pc-q35-2.8</machine>
<machine maxCpus='255'>pc-0.13</machine>
<machine maxCpus='255'>pc-0.14</machine>
<machine maxCpus='255'>pc-i440fx-3.0</machine>
<machine maxCpus='255'>pc-i440fx-2.12</machine>
<machine maxCpus='255'>pc-q35-2.4</machine>
<machine maxCpus='255'>pc-q35-2.5</machine>
<machine maxCpus='255'>pc-q35-2.6</machine>
<machine maxCpus='255'>pc-i440fx-1.4</machine>
<machine maxCpus='255'>pc-i440fx-2.10</machine>
<machine maxCpus='255'>pc-0.11</machine>
<machine maxCpus='255'>pc-0.12</machine>
<machine maxCpus='255'>pc-0.10</machine>
<domain type='qemu'/>
<domain type='kvm'/>
</arch>
<features>
<cpuselection/>
<deviceboot/>
<disksnapshot default='on' toggle='no'/>
<acpi default='on' toggle='yes'/>
<apic default='on' toggle='no'/>
<pae/>
<nonpae/>
</features>
</guest>
<guest>
<os_type>hvm</os_type>
<arch name='x86_64'>
<wordsize>64</wordsize>
<emulator>/usr/bin/qemu-system-x86_64</emulator>
<machine maxCpus='255'>pc-i440fx-3.1</machine>
<machine canonical='pc-i440fx-3.1' maxCpus='255'>pc</machine>
<machine maxCpus='1'>isapc</machine>
<machine maxCpus='255'>pc-1.1</machine>
<machine maxCpus='255'>pc-1.2</machine>
<machine maxCpus='255'>pc-1.3</machine>
<machine maxCpus='255'>pc-i440fx-2.8</machine>
<machine maxCpus='255'>pc-1.0</machine>
<machine maxCpus='255'>pc-i440fx-2.9</machine>
<machine maxCpus='255'>pc-i440fx-2.6</machine>
<machine maxCpus='255'>pc-i440fx-2.7</machine>
<machine maxCpus='128'>xenfv</machine>
<machine maxCpus='255'>pc-i440fx-2.3</machine>
<machine maxCpus='255'>pc-i440fx-2.4</machine>
<machine maxCpus='255'>pc-i440fx-2.5</machine>
<machine maxCpus='255'>pc-i440fx-2.1</machine>
<machine maxCpus='255'>pc-i440fx-2.2</machine>
<machine maxCpus='288'>pc-q35-3.1</machine>
<machine canonical='pc-q35-3.1' maxCpus='288'>q35</machine>
<machine maxCpus='255'>pc-i440fx-2.0</machine>
<machine maxCpus='288'>pc-q35-2.11</machine>
<machine maxCpus='288'>pc-q35-2.12</machine>
<machine maxCpus='288'>pc-q35-3.0</machine>
<machine maxCpus='1'>xenpv</machine>
<machine maxCpus='288'>pc-q35-2.10</machine>
<machine maxCpus='255'>pc-i440fx-1.7</machine>
<machine maxCpus='288'>pc-q35-2.9</machine>
<machine maxCpus='255'>pc-0.15</machine>
<machine maxCpus='255'>pc-i440fx-1.5</machine>
<machine maxCpus='255'>pc-q35-2.7</machine>
<machine maxCpus='255'>pc-i440fx-1.6</machine>
<machine maxCpus='255'>pc-i440fx-2.11</machine>
<machine maxCpus='288'>pc-q35-2.8</machine>
<machine maxCpus='255'>pc-0.13</machine>
<machine maxCpus='255'>pc-i440fx-2.12</machine>
<machine maxCpus='255'>pc-0.14</machine>
<machine maxCpus='255'>pc-i440fx-3.0</machine>
<machine maxCpus='255'>pc-q35-2.4</machine>
<machine maxCpus='255'>pc-q35-2.5</machine>
<machine maxCpus='255'>pc-q35-2.6</machine>
<machine maxCpus='255'>pc-i440fx-1.4</machine>
<machine maxCpus='255'>pc-i440fx-2.10</machine>
<machine maxCpus='255'>pc-0.11</machine>
<machine maxCpus='255'>pc-0.12</machine>
<machine maxCpus='255'>pc-0.10</machine>
<domain type='qemu'/>
<domain type='kvm'/>
</arch>
<features>
<cpuselection/>
<deviceboot/>
<disksnapshot default='on' toggle='no'/>
<acpi default='on' toggle='yes'/>
<apic default='on' toggle='no'/>
</features>
</guest>
</capabilities>
Hardware:
% lshw
description: Desktop Computer
product: HP Compaq Elite 8300 CMT (QV993AV)
vendor: Hewlett-Packard
serial:
width: 64 bits
capabilities: smbios-2.7 dmi-2.7 smp vsyscall32
configuration: administrator_password=disabled boot=normal chassis=desktop family=103C_53307F G=D frontpanel_password=disabled keyboard_password=disabled power-on_password=disabled sku=.. uuid=0049F353-099B-E211-98E4-6C3BE51BF934
*-core
description: Motherboard
product: 3396
vendor: Hewlett-Packard
physical id: 0
serial: ...
*-firmware
description: BIOS
vendor: Hewlett-Packard
physical id: 0
version: K01 v02.83
date: 10/29/2012
size: 64KiB
capacity: 16MiB
capabilities: pci pnp upgrade shadowing cdboot bootselect edd int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification netboot uefi
*-cache:0
description: L1 cache
physical id: 4
slot: CPU Internal L1
size: 256KiB
capacity: 256KiB
capabilities: internal write-through unified
configuration: level=1
*-cache:1
description: L2 cache
physical id: 5
slot: CPU Internal L2
size: 1MiB
capacity: 1MiB
capabilities: internal write-through unified
configuration: level=2
*-cache:2
description: L3 cache
physical id: 6
slot: CPU Internal L3
size: 6MiB
capacity: 6MiB
capabilities: internal write-back unified
configuration: level=3
*-memory
description: System Memory
physical id: 7
slot: System board or motherboard
size: 16GiB
*-bank:0
description: DIMM DDR3 Synchronous 1600 MHz (0.6 ns)
product: M378B5173EB0-YK0
vendor: Samsung
physical id: 0
serial:
slot: DIMM4
size: 4GiB
width: 64 bits
clock: 1600MHz (0.6ns)
*-bank:1
description: DIMM DDR3 Synchronous 1600 MHz (0.6 ns)
product: M378B5173EB0-YK0
vendor: Samsung
physical id: 1
serial:
slot: DIMM3
size: 4GiB
width: 64 bits
clock: 1600MHz (0.6ns)
*-bank:2
description: DIMM DDR3 Synchronous 1600 MHz (0.6 ns)
product: M378B5173EB0-YK0
vendor: Samsung
physical id: 2
serial:
slot: DIMM2
size: 4GiB
width: 64 bits
clock: 1600MHz (0.6ns)
*-bank:3
description: DIMM DDR3 Synchronous 1600 MHz (0.6 ns)
product: M378B5173EB0-YK0
vendor: Samsung
physical id: 3
serial:
slot: DIMM1
size: 4GiB
width: 64 bits
clock: 1600MHz (0.6ns)
*-cpu
description: CPU
product: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
vendor: Intel Corp.
physical id: e
bus info: cpu@0
version: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
slot: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
size: 1637MHz
capacity: 3800MHz
width: 64 bits
clock: 100MHz
capabilities: lm fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp x86-64 constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm cpuid_fault epb pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase smep erms xsaveopt dtherm ida arat pln pts md_clear flush_l1d cpufreq
configuration: cores=4 enabledcores=4 threads=4
*-pci
description: Host bridge
product: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
vendor: Intel Corporation
physical id: 100
bus info: pci@0000:00:00.0
version: 09
width: 32 bits
clock: 33MHz
configuration: driver=ivb_uncore
resources: irq:0
...
*-pci:0
description: PCI bridge
product: 7 Series/C216 Chipset Family PCI Express Root Port 1
vendor: Intel Corporation
physical id: 1c
bus info: pci@0000:00:1c.0
version: c4
width: 32 bits
clock: 33MHz
capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
configuration: driver=pcieport
resources: irq:16 ioport:e000(size=4096) memory:f7c00000-f7cfffff
*-network:0
description: Ethernet interface
product: 82571EB Gigabit Ethernet Controller
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:01:00.0
logical name: enp1s0f0
version: 06
serial: 68:05:ca:1a:a1:94
size: 1Gbit/s
capacity: 1Gbit/s
width: 32 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k duplex=full firmware=5.11-2 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
resources: irq:29 memory:f7ca0000-f7cbffff memory:f7c80000-f7c9ffff ioport:e020(size=32) memory:f7c60000-f7c7ffff
*-network:1
description: Ethernet interface
product: 82571EB Gigabit Ethernet Controller
vendor: Intel Corporation
physical id: 0.1
bus info: pci@0000:01:00.1
logical name: enp1s0f1
version: 06
serial: 68:05:ca:1a:a1:95
size: 1Gbit/s
capacity: 1Gbit/s
width: 32 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k duplex=full firmware=5.11-2 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
resources: irq:31 memory:f7c40000-f7c5ffff memory:f7c20000-f7c3ffff ioport:e000(size=32) memory:f7c00000-f7c1ffff
*-usb:2
description: USB controller
product: 7 Series/C216 Chipset Family USB Enhanced Host Controller #1
vendor: Intel Corporation
physical id: 1d
bus info: pci@0000:00:1d.0
version: 04
width: 32 bits
clock: 33MHz
capabilities: pm debug ehci bus_master cap_list
configuration: driver=ehci-pci latency=0
resources: irq:23 memory:f7d37000-f7d373ff
*-usbhost
product: EHCI Host Controller
vendor: Linux 4.19.0-13-amd64 ehci_hcd
physical id: 1
bus info: usb@4
logical name: usb4
version: 4.19
capabilities: usb-2.00
configuration: driver=hub slots=3 speed=480Mbit/s
*-usb
description: USB hub
product: Integrated Rate Matching Hub
vendor: Intel Corp.
physical id: 1
bus info: usb@4:1
version: 0.00
capabilities: usb-2.00
configuration: driver=hub slots=8 speed=480Mbit/s
*-pci:1
description: PCI bridge
product: 82801 PCI Bridge
vendor: Intel Corporation
physical id: 1e
bus info: pci@0000:00:1e.0
version: a4
width: 32 bits
clock: 33MHz
capabilities: pci subtractive_decode bus_master cap_list
*-isa
description: ISA bridge
product: Q77 Express Chipset LPC Controller
vendor: Intel Corporation
physical id: 1f
bus info: pci@0000:00:1f.0
version: 04
width: 32 bits
clock: 33MHz
capabilities: isa bus_master cap_list
configuration: driver=lpc_ich latency=0
resources: irq:0
*-sata
description: SATA controller
product: 7 Series/C210 Series Chipset Family 6-port SATA Controller [AHCI mode]
vendor: Intel Corporation
physical id: 1f.2
bus info: pci@0000:00:1f.2
logical name: scsi0
logical name: scsi1
logical name: scsi2
version: 04
width: 32 bits
clock: 66MHz
capabilities: sata msi pm ahci_1.0 bus_master cap_list emulated
configuration: driver=ahci latency=0
resources: irq:28 ioport:f0d0(size=8) ioport:f0c0(size=4) ioport:f0b0(size=8) ioport:f0a0(size=4) ioport:f060(size=32) memory:f7d36000-f7d367ff
*-disk:0
description: ATA Disk
product: TOSHIBA HDWD120
vendor: Western Digital
physical id: 0
bus info: scsi@0:0.0.0
logical name: /dev/sda
version: ACF0
serial:
size: 1863GiB (2TB)
capabilities: partitioned partitioned:dos
configuration: ansiversion=5 logicalsectorsize=512 sectorsize=4096 signature=4de1036d
*-volume:0
description: EXT4 volume
vendor: Linux
physical id: 1
bus info: scsi@0:0.0.0,1
logical name: /dev/sda1
logical name: /boot
version: 1.0
serial: 340f09ca-7a41-472e-99e2-d72aecd7517f
size: 285MiB
capacity: 285MiB
capabilities: primary bootable journaled extended_attributes large_files huge_files dir_nlink 64bit extents ext4 ext2 initialized
configuration: created=2020-12-09 19:54:51 filesystem=ext4 lastmountpoint=/boot modified=2020-12-31 21:12:10 mount.fstype=ext4 mount.options=rw,relatime,stripe=4 mounted=2020-12-31 19:21:14 state=mounted
*-volume:1
description: Linux raid autodetect partition
physical id: 2
bus info: scsi@0:0.0.0,2
logical name: /dev/sda2
capacity: 37GiB
capabilities: primary multi
*-volume:2
description: Linux raid autodetect partition
physical id: 3
bus info: scsi@0:0.0.0,3
logical name: /dev/sda3
capacity: 1825GiB
capabilities: primary multi
*-disk:1
description: ATA Disk
product: TOSHIBA HDWD120
vendor: Western Digital
physical id: 1
bus info: scsi@1:0.0.0
logical name: /dev/sdb
version: ACF0
serial:
size: 1863GiB (2TB)
capabilities: partitioned partitioned:dos
configuration: ansiversion=5 logicalsectorsize=512 sectorsize=4096 signature=b3257d2e
*-volume:0
...
It wasn't DRBD that was to blame, those were host and VM cache and IO modes that were the problem,
writethrough
in VM settings and others that apparently reduced disk (rw) throughput to a few hundred kilobytes per second, hencesync
s were extremely slow. After optimizing those the problem went away.