archerslaw

echo "/usr/libexec/qemu-kvm -M pc-i440fx-rhel7.0.0 -cpu Opteron_G2 -enable-kvm -vga none -m 4096 -smp 4,sockets=2,cores=2,threads=1 -usb -device usb-tablet,id=input0 -name sluo -uuid ec15da0a-e8a7-42f4-905a-78fed78fd8fd -rtc base=localtime,clock=host,driftfix=slew -drive file=/home/rhel7-qcow2,if=none,id=drive-ide0-0-0,format=qcow2,cache=none,aio=native,werror=stop,rerror=stop -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -net none -vnc :1 -balloon none -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -monitor stdio -serial unix:/tmp/ttyS0,server,nowait -qmp tcp:0:4444,server,nowait \\" >>ahci-multi-disks-cli.sh
i=0
j=0
while [ $i -lt 30 ]
do
echo "-device ahci,id=ahci$i,addr=0x$(printf "%02x" $((i+2))) \\" >>ahci-multi-disks-cli.sh
for n in 0 $(seq 5);
do
qemu-img create -f raw u$j 1G
echo "-drive file=/home/images/u$j,if=none,id=drive-sata-disk-0-$j,format=raw -device ide-drive,bus=ahci$i.$n,unit=0,drive=drive-sata-disk-0-$j,id=sata-disk-0-$j \\" >>ahci-multi-dis

archerslaw

NOTE: only for raw image and pass-through SCSI disk support it, scsi_id command was provided by Udev is now part of systemd and is installed by default.(e.g.: /usr/lib/udev/scsi_id ...).

# yum install device-mapper.x86_64 device-mapper-multipath.x86_64
# modprobe dm-multipath dm-round-robin
# service multipathd start
Starting multipathd daemon:                                [  OK  ]
# chkconfig multipathd on  //ensure sure that the multipath daemon starts on bootup
# /sbin/mpathconf --enable
# ls -l /etc/multipath.conf
-rw-------. 1 root root 2754 Jan  9 18:55 /etc/multipath.conf

archerslaw

i=1;while [ $i -lt 1300 ]; do qemu-img create -f qcow2 /home/disk/disk$i 1G;i=$(($i+1));done

ulimit -n 10240
cli="/usr/libexec/qemu-kvm -M pc -m 24G -smp 12 -cpu SandyBridge -vnc :1 -monitor stdio -boot menu=on -monitor unix:/tmp/monitor,server,nowait -drive file=/root/RHEL7.0.qcow2,if=none,id=blk1 -device virtio-blk-pci,scsi=off,drive=blk1,id=blk-disk1,bootindex=1 -netdev tap,id=netdev1,vhost=on,script=/etc/qemu-ifup -device virtio-net-pci,netdev=netdev1,mac=02:03:04:05:06:00,id=net-pci1"
cli="$cli -device virtio-scsi-pci,id=scsi0"
cli="$cli -device virtio-scsi-pci,id=scsi1"
count=$((${1:-1}-1))
for i in $(seq 0 $count)
do
j=$((2*$i))

archerslaw

#cat cli-target
cli="/usr/libexec/qemu-kvm -M pc -m 24G -smp 12 -cpu SandyBridge -vnc :1 -monitor stdio -boot menu=on -monitor unix:/tmp/monitor,server,nowait -drive file=/root/RHEL7.0.qcow2,if=none,id=blk1 -device virtio-blk-pci,scsi=off,drive=blk1,id=blk-disk1,bootindex=1 -netdev tap,id=netdev1,vhost=on,script=/etc/qemu-ifup -device virtio-net-pci,netdev=netdev1,mac=02:03:04:05:06:00,id=net-pci1"
cli="$cli -device virtio-scsi-pci,id=scsi0"
count=$((${1:-1}-1))
for i in $(seq 0 $count)
do
echo $i
 cli="$cli -drive file=/home/disk/disk$i,if=none,id=disk$i"
 cli="$cli -device scsi-hd,bus=scsi0.0,drive=disk$i,id=target$i,scsi-id=$i,lun=0"
done

archerslaw

#...-monitor unix:/tmp/monitor2,server,nowait -device virtio-scsi-pci,id=bus1
i=0
j=0
while [ $i -lt 1024 ]
do
    j=$((i%255))
    sleep $((1+i/1000))
    echo "drive_add localhost file=/home/disk/disk$i.qcow2,format=qcow2,media=disk,id=scsi$i,if=none" | nc -U /tmp/monitor2
    echo "device_add scsi-hd,bus=bus1.0,drive=scsi$i,scsi-id=$j,id=hd$i" |nc -U /tmp/monitor2
    i=$(($i+1))

archerslaw

i=1
while [ $i -lt 1024 ]
do
qemu-img create -f qcow2 /home/disk/disk$i.qcow2 1G
i=$(($i+1))
done

archerslaw

RHEL guests:
====================================
              max mem   vCPU
------------------------------------
RHEL3.9-32     16G       16
------------------------------------
RHEL4.9-32     16G       16
------------------------------------
RHEL4.9-64     256G      16
------------------------------------

archerslaw

Note: Despite image file in destination host is qcow2/raw, the format in mirroring command should be raw, check after storage vm migration, the image file in destination should not change.
1.boot qemu-kvm on des host with a empty disk (do two times, once with raw, once with qcow2) and "-incoming tcp:0:$port_cli,server,nowait" and qmp connection.
2.on des host, create NBD server, and export the empty disk:
{ "execute": "qmp_capabilities" }
{"return": {}}
{ "execute": "nbd-server-start", "arguments": { "addr": { "type": "inet", "data": { "host": "$dest_ip_addr", "port": "$port" } } } }
{"return": {}}

{ "execute": "nbd-server-add", "arguments": { "device": "drive-virtio-disk0", "writable": true } }
{"return": {}}

archerslaw

Network Block Device(nbd):
In Linux, a network block device is a device node whose content is provided by a remote machine. Typically, network block devices are used to access a storage device that does not physically reside in the local machine but on a remote one. As an example, the local machine can access a fixed disk that is attached to another computer.

1.start nbd-server to export a qcow2 image with absolute path on the NBD server host.
# nbd-server 12345 /home/my-data-disk.qcow2
2.launch a KVM guest with this exported image as a data disk.
# qemu-img info nbd:10.66.83.171:12345
image: 
file format: qcow2
virtual size: 10G (10737418240 bytes)

archerslaw

1.Boot the guest with multiple queues(queues=4) nic.
e.g:...-device virtio-net-pci,netdev=dev1,mac=9a:e8:e9:ea:eb:ec,id=net1,vectors=9,mq=on
 -netdev tap,id=dev1,vhost=on,script=/etc/qemu-ifup-switch,queues=4

2.Using ethtool -L enable mq in guest
[Guest] # ethtool -L eth0 combined 4

3.Using ethtool -l eth0 can see the channel parameters of the interface like:
Pre-set maximums:
# ethtool -l eth0