Dobrica Pavlinušić's random unstructured stuff
Virtualization workshop: Revision 25
Materijali za "Virtualizacija na Linuxu -- jednostavan izbor zar ne?"<>

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^ Hardware

^^ Disk

Have many disks. More disk spindles brings more than capacity alone! (Same as in databases)

^^^ speed

Slow laptop 2.5" 5400 disk

dpavlin@llin:~$ sudo hdparm -i /dev/sda


Model=FUJITSU MHV2080BH , FwRev=00840028, SerialNo= NW05T6B29HM5
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=DualPortCache, BuffSize=8192kB, MaxMultSect=16, MultSect=?16?
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=156301488
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=yes: mode=0x80 (128) WriteCache=enabled
Drive conforms to: unknown: ATA/ATAPI-3,4,5,6,7

* signifies the current active mode

dpavlin@llin:~$ sudo hdparm -tT /dev/sda
Timing cached reads: 1566 MB in 2.00 seconds = 782.85 MB/sec
Timing buffered disk reads: 66 MB in 3.03 seconds = 21.79 MB/sec

Faster (!) external 3.5 USB disk (no `hdparm -i` on USB), but just because it's *another* disk not loaded by system.

dpavlin@llin:~$ sudo hdparm -tT /dev/sdb

Timing cached reads: 1508 MB in 2.00 seconds = 753.72 MB/sec
Timing buffered disk reads: 56 MB in 3.03 seconds = 18.48 MB/sec

Home-made software md RAID 5 array from SATA drives:

{fetchrss: full}

dpavlin@brr:~$ sudo hdparm -i /dev/sdd


Model=WDC WD5000AAKS-00YGA0 , FwRev=12.01C02, SerialNo= WD-WCAS80929678
Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=50
BuffType=unknown, BuffSize=16384kB, MaxMultSect=16, MultSect=?16?
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=976773168
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=no WriteCache=enabled
Drive conforms to: Unspecified: ATA/ATAPI-1,2,3,4,5,6,7

* signifies the current active mode

dpavlin@brr:~$ sudo hdparm -tT /dev/sda /dev/sdb /dev/sdd

Timing cached reads: 1982 MB in 2.00 seconds = 991.18 MB/sec
Timing buffered disk reads: 232 MB in 3.03 seconds = 76.67 MB/sec

Timing cached reads: 2010 MB in 2.00 seconds = 1004.95 MB/sec
Timing buffered disk reads: 228 MB in 3.01 seconds = 75.85 MB/sec

Timing cached reads: 2006 MB in 2.00 seconds = 1003.01 MB/sec
Timing buffered disk reads: 230 MB in 3.01 seconds = 76.47 MB/sec

dpavlin@brr:~$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd1[0] sda1[2] sdb1[1]
976767872 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

dpavlin@brr:~$ sudo hdparm -tT /dev/md0

Timing cached reads: 1986 MB in 2.00 seconds = 993.20 MB/sec
Timing buffered disk reads: 434 MB in 3.01 seconds = 144.41 MB/sec

As expected RAID 5 speed is 75 + 75 + 0 (parity disk) ~ 144 MB/sec

^^^ temperature

root@brr:~# hddtemp /dev/sda /dev/sdb /dev/sdd
/dev/sda: WDC WD5000AAKS-00YGA0: 33°C
/dev/sdb: WDC WD5000AAKS-00YGA0: 32°C
/dev/sdd: WDC WD5000AAKS-00YGA0: 32°C

^^^ Smart

root@brr:~# smartctl --all /dev/sda | head -20
smartctl version 5.38 [i686-pc-linux-gnu] Copyright (C) 2002-8 Bruce Allen
Home page is

Model Family: Western Digital Caviar Second Generation Serial ATA family
Device Model: WDC WD5000AAKS-00YGA0
Serial Number: WD-WCAS80815866
Firmware Version: 12.01C02
User Capacity: 500,107,862,016 bytes
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Sat Oct 11 00:27:01 2008 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

SMART overall-health self-assessment test result: PASSED

Before you start to beleve in SMART as solution to all disk health problems, read "Failure Trends in a Large Disk Drive Population"<>

^^ CPU

Support for hardware virtualization:

egrep '^flags.*(vmx|svm)' /proc/cpuinfo

How much CPU do I use? :-)

dpavlin@brr:~$ cpufreq-info
cpufrequtils 004: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to, please.
analyzing CPU 0:
driver: acpi-cpufreq
CPUs which need to switch frequency at the same time: 0
hardware limits: 2.40 GHz - 3.20 GHz
available frequency steps: 3.20 GHz, 2.80 GHz, 2.40 GHz
available cpufreq governors: userspace, powersave, ondemand, conservative, performance
current policy: frequency should be within 2.40 GHz and 3.20 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 2.40 GHz.
cpufreq stats: 3.20 GHz:1.80%, 2.80 GHz:0.00%, 2.40 GHz:98.20% (17)


^^ Windows

* `agp440.sys` "killed my VMWare XP installation!"<>

* `intelppm.dll` blue screen of death --

* "Install VBEMP x86 Project Universal VESA/VBE Video Display Driver"<> to get different resolutions on virtual machine

Startup script:

# 3M RFID 810

sudo chown -R $USER /proc/bus/usb/*

kvm -m 512 -hda win-xp.vmdk -no-acpi -std-vga -monitor stdio -usb -usbdevice host:$usbdev

^^ USB sniffing

info usbhost

^ VirtualBox

Seems to be best supported right now (package in Debian, optional drivers for Windows, starting unmodified VMWare machines -- after you guess right settings that is!)

* "Windows ACPI problem"<> - `agp440.sys` problem
* "How to migrate existing Windows installations to VirtualBox"<> - it's applicable to other emulators as well!

^ OpenVZ

^^ Add disk space to VE

First, resize logical volume:

root@koha-hw:~# vgextend -L +80G /dev/vg/vz
vgextend: invalid option -- L
Error during parsing of command line.

root@koha-hw:~# lvextend -L +80G /dev/vg/vz
Extending logical volume vz to 100.00 GB
Logical volume vz successfully resized

root@koha-hw:~# resize2fs /dev/vg/vz
resize2fs 1.40-WIP (14-Nov-2006)
Filesystem at /dev/vg/vz is mounted on /vz; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 7
Performing an on-line resize of /dev/vg/vz to 26214400 (4k) blocks.
The filesystem on /dev/vg/vz is now 26214400 blocks long.

root@koha-hw:~# df -h /vz/
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg-vz 99G 20G 79G 21% /vz

Then, take a look how much space does VEs take:

root@koha-hw:~# vzlist -o veid,diskspace,diskspace.s,diskspace.h,diskinodes,diskinodes.s,diskspace.h
212052 11717220 15728640 20971520 61001 286527 20971520
212226 6407804 10485760 12582912 69011 435472 12582912

alternativly, you can also execute df inside VEs:

root@koha-hw:~# vzlist -o veid -H | xargs -i sh -c "echo --{}-- ; vzctl exec {} df -h"
Filesystem Size Used Avail Use% Mounted on
simfs 15G 12G 3.9G 75% /
tmpfs 2.0G 0 2.0G 0% /lib/init/rw
tmpfs 2.0G 0 2.0G 0% /dev/shm
Filesystem Size Used Avail Use% Mounted on
simfs 10G 6.2G 3.9G 62% /
tmpfs 2.0G 0 2.0G 0% /lib/init/rw
tmpfs 2.0G 0 2.0G 0% /dev/shm

next, we will set diskpace on both VEs (becase we want them to share all available resources) to new logical volume size:

root@koha-hw:~# vzlist -o veid -H | xargs -i vzctl set {} --diskspace 100G:100G --save
Saved parameters for VE 212052
Saved parameters for VE 212226

This VEs are not in production, and one is development version of another. When we move to production, we want to enforce more strict limit on disk usage, to protect production machine from running out of disk space in case the development one goes wild.

^ VMWare

^^ Convert image to monolithic growable disk

This format is supported by other emulators, so it's a best choice.

dpavlin@llin:/rest/vmware/winxp$ vmware-vdiskmanager -r Windows\ XP\ Professional.vmdk -t 0 /mnt/usb/vmware/win-xp.vmdk
Using log file /tmp/vmware-dpavlin/vdiskmanager.log
Creating a monolithic growable disk '/mnt/usb/vmware/win-xp.vmdk'
Convert: 57% done.


^^ Resize disk image

dpavlin@llin:/mnt/usb/vmware$ qemu-img info win-xp.vmdk
(VMDK) image open: flags=0x2 filename=win-xp.vmdk
image: win-xp.vmdk
file format: vmdk
virtual size: 3.0G (3221225472 bytes)
disk size: 3.0G

There is a way to extend image using only `qemu-img`, but that involves converting image to raw and appending zeros at end to produce larger image. However, we will do that using VMWare's `vmware-vdiskmanager`

dpavlin@llin:/mnt/usb/vmware$ vmware-vdiskmanager -x 6Gb win-xp.vmdk
Using log file /tmp/vmware-dpavlin/vdiskmanager.log
Grow: 100% done.
The old geometry C/H/S of the disk is: 6241/16/63
The new geometry C/H/S of the disk is: 12483/16/63
Disk expansion completed successfully.

WARNING: If the virtual disk is partitioned, you must use a third-party
utility in the virtual machine to expand the size of the
partitions. For more information, see:

This will make disk unbootable, so we will have to resize partition. Download "GParted"<> live CD and resize partition using it...

kvm -m 512 -hda win-xp.vmdk -no-acpi -std-vga -cdrom /rest/iso/gparted-live-0.3.9-4.iso -boot d

^^ Convert vmdk to qcow

dpavlin@llin:/mnt/usb/vmware$ qemu-img convert -O qcow win-xp.vmdk win-xp.qcow
(VMDK) image open: flags=0x2 filename=win-xp.vmdk
dpavlin@llin:/mnt/usb/vmware$ ls -al win-xp.*
-rw-r--r-- 1 dpavlin dpavlin 3190906880 Oct 9 17:41 win-xp.qcow
-rw------- 1 dpavlin dpavlin 3208577024 Oct 9 17:35 win-xp.vmdk