archerslaw

1.GlusterFS is an open source, distributed file system capable of scaling to several petabytes (actually, 72 brontobytes!) and handling thousands of clients. GlusterFS clusters together storage building blocks over Infiniband RDMA or TCP/IP interconnect, aggregating disk and memory resources and managing data in a single global namespace. GlusterFS is based on a stackable user space design and can deliver exceptional performance for diverse workloads. Goal of this translator is to use logical volumes to store VM images and expose them as files to QEMU/KVM.

2.Quick start.
1).Install gluster server.
glusterfs-server
https://brewweb.devel.redhat.com/buildinfo?buildID=350720
2).Create brick.
# mkdir -p /home/brick1
3).Start gluster service.
# /bin/systemctl start  glusterd.service

archerslaw

Test Matrix:
      Filesystem: ext4 and xfs and scsi_debug for host side, and ext4 or xfs for guest side.
      Backend: localfile or iSCSI or libiscsi (Note: BZ#1037503 glusterfs not support discard).
      Disk Format: RAW for passthrough, RAW/qcow2 for localfile.
      Disk Interface: scsi-block/scsi-hd/ide/ahci for UNMAP mode, scsi-block/scsi-hd interface for WRITE SAME mode.
      NOTE: Persistent reservations *cannot* be used with discard when QEMU run as non-root user, but can work well in root user.(BZ966883#c5)

Windows only supports automatic discard (like "-o discard" in Linux).  
You can check that discard is enabled by running.

archerslaw

##
# @BlockdevOptionsBase
#
# Options that are available for all block devices, independent of the block
# driver.
#
# @driver:      block driver name
# @id:          #optional id by which the new block device can be referred to.
#               This is a required option on the top level of blockdev-add, and
#               currently not allowed on any other level.

archerslaw

- AMD & Intel:

Opteron_G4: avx,xsave,aes,sse4.2,sse4.1,cx16,ssse3,sse4a

Opteron_G3: cx16,sse4a

Opteron_G2: cx16

Opteron_G1: no cx16

archerslaw

###### Bridge network configuration.

# cat /etc/qemu-ifup 
#!/bin/sh
switch=switch
/sbin/ifconfig $1 0.0.0.0 up
/usr/sbin/brctl addif ${switch} $1

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"

archerslaw

import libvirt
conn = libvirt.open('qemu:///system')
for id in conn.listDomainsID():
	dom = conn.lookupByID(id)
	print "Dom %s  State %s" % ( dom.name(), dom.info()[0] )
	dom.suspend()
	print "Dom %s  State %s (after suspend)" % ( dom.name(), dom.info()[0] )
	dom.resume()
	print "Dom %s  State %s (after resume)" % ( dom.name(), dom.info()[0] )
	dom.destroy()

archerslaw

# QEMU Monitor Protocol Python class
#
# Copyright (C) 2009 Red Hat Inc.
#
# This work is licensed under the terms of the GNU GPL, version 2.  See
# the COPYING file in the top-level directory.

import socket, json, time, commands
from optparse import OptionParser

archerslaw

# /bin/systemctl restart  libvirtd.service
# /bin/systemctl enable  libvirtd.service

Note:
How to turn on the debug logs for libvirtd.
1)open /etc/libvirt/libvirtd.conf in your favourite editor.
2)find & replace, or set these variables:
log_level = 1
log_filters="3:remote 4:event 3:json 3:rpc" | log_filters="1:qemu_monitor_json"
log_outputs="1:file:/var/log/libvirt/libvirtd.log"

archerslaw

<domain type='kvm'>
  <name>sluo_kvm_example</name>
  <uuid>fd509219-5ace-4102-90bd-d4312a85a363</uuid>
  <memory unit='KiB'>1048576</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <resource>
    <partition>/machine</partition>
  </resource>
  <os>

archerslaw

import re
import sys
import os

def filerev(somefile, buffer=256):
  somefile.seek(0, os.SEEK_END)
  size = somefile.tell()
  lines = ['']
  rem = size % buffer
  pos = max(0, (size // buffer - 1) * buffer)