• 开启Intel VT-x/VT-d/VMDq/SR-IOV
• 开启CR3(控制寄存器3)
• 开启超线程支持
• 关闭节电模式
• 独立主板固态硬盘启动、U盘启动

There have been some pretty major IO performance boosts in the past few kernel releases, in some cases you might see 25% more random read or write IOPS if you are using an SSD.

• Kernel 3.17 SCSI Multi-Queue - http://www.phoronix.com/scan.php?page=news_item&px=MTcyMjk
• Kernel 3.19 multi-queue block layer (blk-mq) - http://www.phoronix.com/scan.php?page=news_item&px=MTg2Mjg

If you're running Ubuntu with a kernel that's older than 3.19, and you have an SSD, you are probably only getting 50% - 75% of it's potential speed. I'm not joking, the performance gains are huge between Kernel 3.13 and 3.19 even for Ubuntu. CentOS 7 / RHEL just got to Kernel 3.10 which sucks slightly less than CentOS 6 2.6.something, which is just depressing when it comes to SSD IO performance.

• 安装必要软件包：Virtualhost & Developments

• 安装最新的spice-protocol,spice-server(强制卸载spice-server-0.12.4-11.el6.x86_64 –nodeps)

• 重新编译qemu最新稳定版本: 2.1.3(最稳定，够用，参考qboot编译参数，替换系统自带)

./configure --prefix=/opt --target-list=x86_64-softmmu --enable-linux-aio \ 
            --enable-numa --enable-spice --enable-kvm --enable-lzo --enable-snappy \
            --enable-libusb --enable-usb-redir --enable-libiscsi --enable-mc --enable-rdma \
            --disable-libnfs --disable-seccomp --disable-smartcard-nss --disable-fdt --disable-curl \
            --disable-curses --disable-sdl --disable-gtk  --disable-tpm --disable-vte --disable-xen  \
            --disable-cap-ng 

yum install -y numactl lzo snappy pixman celt051

net.core.netdev_max_backlog = 262144
net.ipv4.tcp_sack = 0
net.ipv4.tcp_dsack = 0
net.ipv4.tcp_rmem = 8192 87380 6291456
net.ipv4.tcp_wmem = 8192 87380 6291456
net.ipv4.tcp_mem = 786432 1048576 1572864
net.ipv4.tcp_syncookies = 0
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_app_win = 40
net.ipv4.tcp_early_retrans = 1

vm.swappiness=0

grep -E "ept|vpid" /proc/cpuinfo
cat /sys/module/kvm_intel/parameters/ept
cat /sys/module/kvm_intel/parameters/vpid

modprobe kvm_intel ept=1,vpid=1

grep Hugepagesize /proc/meminfo
mount -t hugetlbfs hugetlbfs /dev/hugepages
sysctl vm.nr_hugepages=1024

qemu-kvm –mem-path /dev/huagepages

服务器开启定时同步时间服务

虚拟机也可以设置定时时间同步任务

• Kernel Virtual Machine
• 虚拟化之QEMU与KVM

Usually both options are recommended for:

Important note from Red Hat: Direct Asynchronous IO (AIO) that is not issued on filesystem block boundaries, and falls into a hole in a sparse file on ext4 or xfs filesystems, may corrupt file data if multiple I/O operations modify the same filesystem block. Specifically, if qemu-kvm is used with the aio=native IO mode over a sparse device image hosted on the ext4 or xfs filesystem, guest filesystem corruption will occur if partitions are not aligned with the host filesystem block size. Generally, do not use aio=native option along with cache=none for QEMU. This issue can be avoided by using one of the following techniques:

• Align AIOs on filesystem block boundaries, or do not write to sparse files using AIO on xfs or ext4 filesystems.
• KVM: Use a non-sparse system image file or allocate the space by zeroing out the entire file.
• KVM: Create the image using an ext3 host filesystem instead of ext4.
• KVM: Invoke qemu-kvm with aio=threads (this is the default).
• KVM: Align all partitions within the guest image to the host’s filesystem block boundary (default 4k).

* cache=writeback,aio=threads
* schelder = deadline/cfq
* acpi=off
* preallocation = metadata

尽量模拟多路多核多线程，让软件自动识别，maxcpus hotplug cpu有bug风险，暂时不建议使用

宿主机尽量保留1路1核给自有系统使用，使用isolcpus

-smp 4,sockets=2,cores=2,threads=1/2

• http://www.phoronix.com/scan.php?page=news_item&px=MTM4ODA
• https://wiki.archlinux.org/index.php/Bcache
• http://blog.csdn.net/werm520/article/details/42639201
• https://github.com/stec-inc/EnhanceIO
• http://www.sebastien-han.fr/blog/2014/10/06/ceph-and-enhanceio/
• http://blackbird.si/enhancedio-block-cache-howto-and-benchmark/

• http://www.ibm.com/developerworks/cn/linux/l-cn-btrfs/index.html
• http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide
• https://wiki.gentoo.org/wiki/ZFS
• http://blog.virtual-on.org/2011/10/zfs3-zfs.html
• http://blog.163.com/digoal@126/blog/static/1638770402014526992910/
• http://blog.163.com/digoal@126/blog/static/16387704020145253599111/
• http://fibrevillage.com/storage/171-zfs-on-linux-performance-tuning

ZFS + L2ARC and ZIL on ssd.

1. Performance was good. The L2ARC algoritihms are far more sophisticated than the moes for bcache or EnhanceIO, long term usage should benefit
2. A delight to work with, so flexible and clear. Great command line tool set, very easy to see what is going on. The ability to add multiple SSD's fo cache is amazing.
3. ZFS. Amazing powerful soft raid setup. Snapshots. Backups, Send/Recv, Compression, Deduplication.

dm-Cache:

1. Complicated to setup
2. Fiddly and error prone to manage
3. Needs custom init scripts
4. No auto ignoring of bulk reads/writes (disk cloning, backups)
5. I managed to destroy the underlying file system while attempting to flush and dismount the write cache.
6. Did give good results for reads/writes

bcache

1. User tools have to be compiled and installed
2. can't be used with existing file systems
3. No auto ignoring of bulk reads/writes (disk cloning, backups)
4. Needs custom init scripts
5. 3.10 kernel version is hopelessly buggy. Trashed the file system
6. No tools for uninstalling. Required a hard result and then I had to use dd to overwrite the partition table to remove the cache store. I then blacklisted the module

EnhanceIO

1. Has to be compiled and installed
2. can be used with existing file systems
3. Can be created/edited/destroyed on the fly
4. No auto ignoring of bulk reads/writes (disk cloning, backups)
5. persistent between reboots (udev rules)
6. Good results on reads/writes
7. Unfortunately when I combined it with an external ext4 journal I got data corruption

ZFS (zfsonlinux.org)

1. Used the kernel module
2. has a repo, but required kernel headers, build-essentials and dkms.
3. Builtin support for journal and read caching using multiple SSD's
4. ZFS! with all the zfs goodies, raid, striping, snapshots, backups, pool managment.
5. Auto ignoring of bulk reads/writes (disk cloning, backups)
6. good tools for management and reporting disk/cache stats and errors
7. I restricted it to 1GB RAM on Hosts
8. Good results on reads/writes
9. No support for O_DIRECT so I had to disable glusters io cache, which is recommenced anyway for virtual stores.

options zfs zfs_arc_max=40000000000
options zfs zfs_vdev_max_pending=24
Where zfs_arc_max is roughly 40% of your RAM in bytes (Edit: try zfs_arc_max=1200000000). The compiled-in default for zfs_vdev_max_pending is 8 or 10, depending on version. The value should be high (48) for SSD or low-latency drives. Maybe 12-24 for SAS. Otherwise, leave at default.
 
You'll want to also have some floor values in /etc/sysctl.conf
 
vm.swappiness = 10
vm.min_free_kbytes = 512000
Finally, with CentOS, you may want to install tuned and tuned-utils and set your profile to virtual-guest with tuned-adm profile virtual-guest.
 
Try these and see if the problem persists.
 
Edit:
 
Run zfs set xattr=sa storage. Here's why. You may have to wipe the volumes and start again (I'd recommend).

#!/bin/sh
echo "options zfs zfs_prefetch_disable=1" > /etc/modprobe.d/zfs.conf
echo "options zfs l2arc_noprefetch=0" >> /etc/modprobe.d/zfs.conf
awk '/MemTotal/{printf "options zfs zfs_arc_min=%.f\n",$2*1024*1/10}' /proc/meminfo >> /etc/modprobe.d/zfs.conf
awk '/MemTotal/{printf "options zfs zfs_arc_max=%.f\n",$2*1024*3/10}' /proc/meminfo >> /etc/modprobe.d/zfs.conf
 
[ -z "$1" ] && echo "$0 poolname" && exit 0
zpool create $1 -f -o ashift=12 raidz \
        -O atime=off \
        -O relatime=on \
        -O compression=lz4 \
        -O primarycache=all \
        -O secondarycache=all \
        -O logbias=throughput  \
        -O dedup=off \
        -O casesensitivity=mixed /dev/sd[bcde]
zpool add $1 -f cache sda3

mkfs.xfs -L /ssd1 -l internal,lazy-count=1,size=128m -i attr=2 -d agcount=8 -i size=512 -f /dev/sda4
mount -t xfs -o rw,noexec,nodev,noatime,nodiratime,barrier=0,logbufs=8,logbsize=256k /dev/sda4 /storage
 
[root@vcn40 storage]# time dd if=/dev/zero of=2g bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 31.1406 s, 673 MB/s
 
real	0m31.143s
user	0m0.010s
sys	0m16.413s
[root@vcn40 storage]# echo 3 > /proc/sys/vm/drop_caches 
[root@vcn40 storage]# time dd if=/dev/zero of=2g bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 30.6331 s, 685 MB/s
 
real	0m31.501s
user	0m0.013s
sys	0m16.881s

[root@vcn40 ~]# cd /storage
[root@vcn40 storage]# time dd if=/dev/zero of=2g bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 31.835 s, 659 MB/s
 
real	0m31.837s
user	0m0.010s
sys	0m25.371s
[root@vcn40 storage]# echo 3 > /proc/sys/vm/drop_caches 
[root@vcn40 storage]# time dd if=/dev/zero of=2g bs=1M count=20000
20000+0 records in
20000+0 records out
20971520000 bytes (21 GB) copied, 58.9783 s, 356 MB/s
 
real	0m59.003s
user	0m0.013s
sys	0m27.882s

• 网卡特性优化
• 网卡吞吐量测试
• How to use get high performance with Virtio
• KVM虚拟化网络优化技术总结
• SCTP vs TCP vs UDP的可行性
• KVM Bonding&Bridge+VLAN
• 10G 网络升级(服务器端 bonding)

       options bonding max_bonds=2 mode=4 
                miimon=100 downdelay=100 updelay=100 
                lacp_rate=1  use_carrier=1
                xmit_hash_policy=layer3+4

• spice console in openstack
• jsonutils sync breaks if simplejson < 2.2.0

• 图形显示: (mozjpeg > zstd > lz4 > quicklz)
• 视频显示: (h264 > xvid > mjpeg2000 > mjpeg) 参考链接

yum install -y python-setuptools libjpeg-devel cyrus-sasl-devel openssl-devel celt051-devel alsa-lib-devel glib2-devel libXrandr-devel libXinerama-devel xorg-x11-server-devel gcc gcc-c++ autoconf automake

vi /usr/bin/startyc

#!/bin/sh
cd /usr/local/bin/MiGateway/
./ycc

vi /etc/rc.d/rc.local

/usr/bin/xinit /usr/bin/startyc

如果是使用systemd来管理启动进程 systemd

vi /etc/systemd/system/rc.local.service

[Unit]
Description=/etc/rc.local Compatibility
ConditionPathExists=/etc/rc.local
 
[Service]
Type=forking
ExecStart=/etc/rc.local start
TimeoutSec=0
StandardOutput=tty
RemainAfterExit=yes
SysVStartPriority=99
 
[Install]
WantedBy=multi-user.target

systemd enable rc.local.service

mkusb.sh

#!/bin/sh
[ -z $1 ] && echo "$0 /dev/sdX" && exit 0
DEV=$1
IMG="/root/ycos_client_xinit.tgz"
 
FORMAT_FORCE="y"
MOUNT_POINT="/mnt/"
 
if [ $FORMAT_FORCE = "y" ];then
        fdisk $DEV<<EOF
d
3
d
2
d
n
p
1
1
+4096M
n
p
2
 
+1024M
n
p
3
 
 
t
2
82
a
1
 
w
EOF
partx -a $DEV
sleep 3
 
mkfs.ext4 -L /Amy ${DEV}1
mkswap -L /Swap ${DEV}2
fi
 
mount -f ${DEV}1 $MOUNT_POINT
tar zxvf $IMG -C $MOUNT_POINT
 
mount ${DEV}1 $MOUNT_POINT
tar zxvf $IMG -C $MOUNT_POINT
grub-install --root-directory=$MOUNT_POINT --no-floppy --recheck $DEV
umount $MOUNT_POINT

• Running Windows 7 guests on OpenStack Icehouse

• IDE → VirtIO
• 硬raid/软mdadm → ZFS RaidZ+SSD240/320G

yum install -y inotify-tools rsync

/usr/local/bin/inotify_rsync.sh

#!/bin/sh
SRC="/xx/"
DST="/root/xx/"
HOSTS="10.0.2.47 10.0.2.48"
SSH_OPTS="-i/root/.ssh/id_rsa -p65422 -x -T -c arcfour -o Compression=no -oStrictHostKeyChecking=no"
 
# Don't change below
NUM=($HOSTS)
NUM=${#NUM[*]}
SPEED=$((100000/$NUM))
/usr/bin/inotifywait -mrq -e close_write,delete --format '%f' $SRC | while read files;do
        for ip in $HOSTS;do
        echo $files
        rsync -aP --bwlimit=$SPEED --delete -e "ssh $SSH_OPTS" $SRC root@$ip:$DST
        done
done

nohup /usr/local/bin/inotify_rsync.sh 1>&2>/var/log/rsync.log &

yum install supervisor

[program:vcnagent]
command=/opt/vcn/vdi/vcnagent "-info"
;environment=PATH=/opt/bin:/opt/sbin:%(ENV_PATH)s
priority=999
autostart=true
autorestart=true
startsecs=10
startretries=3
exitcodes=0,2
stopsignal=QUIT
stopwaitsecs=10
user=root
log_stdout=true
log_stderr=true
logfile=/var/log/vcnagent.log
logfile_maxbytes=1MB
logfile_backups=10

• Vdagent can not run
• Windows Virtio Drivers
• virtio-win-0.1-100.iso
• Disable windows WHQL

bcdedit -set loadoptions DISABLE_INTEGRITY_CHECKS
bcdedit -set TESTSIGNING ON

• J60是杰云科技自主研发的瘦客户机（Thin Client）

• RHEV KVM SRPM
• KVM性能优化方案
• KVM性能优化
• KVM性能调优
• KVM CPU Qos
• kvm-performance-optimization-for-ubuntu
• OpenStack虚拟机镜像修改
• Ubuntu 12.10安装和配置KVM Windows7 Guest
• kvm、spice安装Windows 7备忘录
• 为OpenStack制作Windows 2008 R2镜像
• Archlinux QEMU
• CentOS QEMU
• kvm使用小结
• kvm 图形化虚拟的解决方法
• openstack 性能测试
• KVM CPU测试环境配置