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1612 discussions

Re: [CentOS-virt] Bad Disk Performance of domU
by Christopher G. Stach II 26 May '09

26 May '09

----- "Francisco Pérez" <fperez.x(a)gmail.com> wrote: > I guess the bad performance it goes with the writing. For example on > decompression of a big tar.gz, installing rpm packages. Also on > restoring a MySQL Database... > > The first clue when i knew that something were wrong was on the FS > formating stage. It took really long time to format 40 GB to ext3. I > did the same on other machine with a sata disk... surprise! same > software and hardware config except for the inferior disk type and did > it in no time. It sounds like your the virtual disk file is sparse. If that's the case, you traded performance for space. It not only has to deal with the underlying filesystem, but it allocates the space on demand and hits that filesystem's journal. Try an LVM logical disk and see how that performs. -- Christopher G. Stach II

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Profiling tools
by lists＠zfobjects.com 26 May '09

26 May '09

I'm wondering if anyone has suggestions for profiling tools (RAM, CPU, disc IO) suitable for helping estimate the resource requirements of physical machines destined for virtualisation? Preferably open source, and capable of running on Linux or Windows, but anything at all really. I know that CentOS has a suite of "sysstat" utilities and /proc files that can probably provide the answers, I am looking at scripting something up with them if necessary.

2 1

Dynamic XEN USB usage for Win Guest?
by Hildebrand, Nils, 232 26 May '09

26 May '09

Hi, I am trying to attach a Palm Z22 via USB to my fully virtualized Win XP. Dom0-System: CentOS 5.3 x86_64 (Kernel 2.6.18.128.1.10.el5xen) XEN: 3.0.3-80.el5_3.2 XP: 32-Bit Professional lsusb shows: USB Palm: Bus 002 Device 007: ID 0830:0061 Palm, Inc. Lifedrive / Treo 650/680 / Tunsten E2/T5/TX / Zire 21/31/72 / Z22 I found some hints that I have to put usb = 1 and usbdevice = "host:0830:0061" into my DomU-config. When I start the DomU without the device switched on I get (qemu.log): Warning: could not add USB device host:0830:0061 I/O request not ready: 0, ptr: 0, port: 0, data: 0, count: 0, size: 0 I/O request not ready: 0, ptr: 0, port: 0, data: 0, count: 0, size: 0 Triggered log-dirty buffer switch When I start the DomU with the device switched on I don't get this error - but the usb-device does not appear in XP. Questions: - why does the device not appear in XP? - is there a way to dynamically attach the usb-device (it is not present the whole time!)? - in the CentOS documentation abot xen (virtualization guide) I found an option "usbport" but I have found no exaple on how to use it - would this work instead? http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization -Configuration_files.html search for "usbport". Kind regards Nils

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No cpu throttling for Xeon E5405?
by Dennis J. 23 May '09

23 May '09

Hi, we bought some machines with 2 x quad core Xeon E5405 processors and installed centos 5.3 on them. My problem is that I can't get the cpuspeed service to work. No driver seems to claim responsibility for the throttling and the fallback "modprobe acpi_cpufreq" in the cpuspeed init script just yields a "No such device" message. According to the acpi information the CPUs should support this just fine: cat /proc/acpi/processor/CPU0/info: processor id: 0 acpi id: 0 bus mastering control: yes power management: no throttling control: yes limit interface: yes cat /proc/acpi/processor/CPU0/throttling: state count: 8 active state: T0 states: *T0: 00% T1: 12% T2: 25% T3: 37% T4: 50% T5: 62% T6: 75% T7: 87% At least half of the cores aren't really used at the moment under non-peak load so we are wasting quite a bit of power with this. Any idea on how to get this working? Regards, Dennis

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Re: [CentOS-virt] Bad Disk Performance of domU
by Christopher G. Stach II 20 May '09

20 May '09

----- "Francisco Pérez" <fperez.x(a)gmail.com> wrote: > OK, here it is: > > name = "vm01" > uuid = "2fa05fe5-9b52-3527-5bf5-efb88555c567" > maxmem = 5836 > memory = 5836 > vcpus = 1 > bootloader = "/usr/bin/pygrub" > on_poweroff = "destroy" > on_reboot = "restart" > on_crash = "restart" > vfb = [ ] > disk = [ "tap:aio:/var/lib/xen/images/vm01.img,xvda,w" ] > vif = [ "mac=00:16:3e:15:6f:cd,bridge=xenbr0" ] > > Thanks. What kind of "disk performance"? Read? Write? Random? Linear? As for general tuning, use block devices (LVM) unless you have to do otherwise. Do you do a large amount of I/O in general? Do you have dom0's CPU pinned to an unshared core? -- Christopher G. Stach II

2 1

Bad Disk Performance of domU
by Francisco Pérez 19 May '09

19 May '09

Hi list. Im Running xen on a brand new dell PE 1950 with 146 GB SAS Disk on raid1. The performance on the I/O on the domU is really poor, but in dom0 the performance is great. Any ideas? Regards Francisco.

2 4

Machine freeze
by Maros TIMKO 05 May '09

05 May '09

Hi all, we are running CentOS 5.2 Xen virtualization system with the latest CentOS packages with couple of VMs on DELL PowerEdge. "Sometimes" the whole machine freezes without anything in log files, anything on the console. "Sometimes" really means we cannot define why or when. Sometimes the machine was idle with just one VM, sometimes quite busy with couple of VMs.  Has anybody had the same experience? If yes, any hints on how to resolve it or how to trace the cause?   Thanks. 

8 14

gentoo
by mattias 03 May '09

03 May '09

How to install gentoo with virt-install I not use full virtualization Only xen para or what the name are So i can't use virtual cd

1 0

Virt-install
by mattias 29 Apr '09

29 Apr '09

Exuse all my questiosn but i not find any info about virt-install on centos.org So how install e.g debian with virt-install with an iso?

3 5

xen
by mattias 28 Apr '09

28 Apr '09

Have anyone get a ubuntu guest worked in centos? I try now but only recive errors insmod: error inserting '/lib/scsi_mod.ko': -1 Operation not permitted Loading sd_mod.ko module ksign: module signed with unknown public key - signature keyid: 88a2b9299d40c296 ver=3 insmod: error inserting '/lib/sd_mod.ko': -1 Operation not permitted Loading libata.ko module ksign: module signed with unknown public key - signature keyid: 88a2b9299d40c296 ver=3 insmod: error inserting '/lib/libata.ko': -1 Operation not permitted Loading ata_piix.ko module ksign: module signed with unknown public key - signature keyid: 88a2b9299d40c296 ver=3 insmod: error inserting '/lib/ata_piix.ko': -1 Operation not permitted Loading dm-mod.ko module ksign: module signed with unknown public key - signature keyid: 88a2b9299d40c296 ver=3 insmod: error inserting '/lib/dm-mod.ko': -1 Operation not permitted Loading dm-log.ko module ksign: module signed with unknown public key - signature keyid: 88a2b9299d40c296 ver=3 insmod: error inserting '/lib/dm-log.ko': -1 Operation not permitted Loading dm-mirror.ko module I use kernel = "/boot/vmlinuz-2.6.18-128.el5xen" ramdisk = "/boot/initrd-2.6.18-128.1.6.el5xen" Any tip?

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