virt September 2009

virt@lists.centos.org

26 participants
15 discussions

High CPU usage when running a CentOS guest in VirtualBox
by Sagi Bashari 16 Nov '09

16 Nov '09

Hi, I am running CentOS 5.3 32bit as a VirtualBox 3.0.0 guest running on Windows XP. The Windows host CPU usage is constantly at 50% although the CentOS guest is completely idle (i.e. 0.00 load average). I know this is a common problem related to the 1000Hz frequency that the CentOS kernel runs at. With previous versions of CentOS, I used the kernel-vm package [1] and it solved my problem. However, according to the README [2] this isn't necessary as of CentOS 5.3 and therefore these packages are not maintained anymore (the latest released kernel-vm is 2.6.18-92.1.22). >From what I understand, as of CentOS 5.3 it is possible to use the "divider=10 clocksource=acpi_pm" to reduce the frequency to 100Hz. I tried this setting, and it made no difference at all. I also tried to install the VirtualBox guest extensions, and still, the host CPU never goes below 50%. Is there any way to solve this issue without resorting to a custom kernel build? Thanks, Sagi [1] http://people.centos.org/tru/kernel-vm/ [2] http://people.centos.org/tru/kernel-vm/readme.txt

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Domain0 with Kernel 2.6.18-92.1.22.el5xen fails to boot Guests with Kernel 2.6.18-164.el5xen
by Devraj Mukherjee 09 Nov '09

09 Nov '09

Hi all, I am in a bit of a fix here, I have several Guests paravirtualized running on a Dom0 that is currently running the 2.6.18-92.1.22.el5xen Kernel. All my guests (administered by different people) have subsequently been updated to later versions of the kernel (namely 2.6.18-164.el5xen or 2.6.18-128.4.1.el5xen). Ones that are still running are using the Kernel 2.6.18-128.4.1.el5xen while Dom0 is still booted up into 2.6.18-92.1.22.el5xen I restarted a Guest that's now trying to boot with the 2.6.18-164.el5xen Kernel and it spits out messages like XENBUS: Waiting for devices to initialise: 295s...290s... and eventually reboots. If I try and interrupt the boot and choose a previous version of the Kernel on the Guest, it says the following and fails to boot. The guests use a single disk image that has the SWAP and Root partitions. Is this happening because the version of the kernel on the Dom0 is way too old for guests to boot? I am just a bit hesitant in rebooting my server for the new kernel to take effect unless I am sure :) device-mapper: dm-raid45: initialized v0.2429 Scanning and configuring dmraid supported devices Scanning logical volumes Reading all physical volumes. This may take a while... Activating logical volumes Volume group "VolGroup00" not found Creating root device. Mounting root filesystem. mount: could not find filesystem '/dev/root' Setting up other filesystems. Setting up new root fs setuproot: moving /dev failed: No such file or directory no fstab.sys, mounting internal defaults setuproot: error mounting /proc: No such file or directory setuproot: error mounting /sys: No such file or directory Switching to new root and running init. unmounting old /dev unmounting old /proc unmounting old /sys switchroot: mount failed: No such file or directory Kernel panic - not syncing: Attempted to kill init! -- "The secret impresses no-one, the trick you use it for is everything" - Alfred Borden (The Prestiege)

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SATA vs RAID5 vs VMware
by Philip Gwyn 03 Nov '09

03 Nov '09

Hello, I have strange behaviour on a server that I can't get a handle on. I have a reasonably powerful server running VMware server 1.0.4-56528. It has a RAID5 build with mdadm on 5 SATA drives. Masses of ram and 2 XEON CPUs. But it stutters. Example : fire up vi, press and keep finger on i. After filling 2-3 lines, the display is stopped for 2-12 seconds. Then they continue. This happens even on the host OS, at the console. Host system running CentOS 5.2 x86-64: CPU : 2x Xeon E5430 @ 2.66GHz RAM : 24GB Mobo : DSBV-DX HD : 5 x SATA ST3750330AS 750GB in RAID5 There are 5 VMs, detailed at http://www.awale.qc.ca/vmware/stj1.txt to make this mail shorter. Seems to me this system should be more then adequate to handle the load. This is what vmstat on the host looks like when the server is "unhappy" : http://www.awale.qc.ca/vmware/vmstat.txt Spending a lot of time in 'wa', but 'bo' and 'bi' are miniscule. The problem seems like a disk problem. I grow to suspect that SATA isn't ready for the big time. I also grow to dislike RAID5. Questions : - Anyone have a clue or other on how to track down my bottle neck? - SATA NCQ is limited to 15 queue depth. Is this per-SATA-port or per-SATA-chip? Or does this question make no sense? - I realise there are more recent versions of CentOS out. Are there specific items in the changelogs that would affect my problem? Thank you for any help, -Philip

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domU shutdown with cx88 crashes dom0
by Christian Schuermann 10 Oct '09

10 Oct '09

Hi, I've got a big problem with a cx88 DVB card. It is passed through to a CentOS 5.3 domU (dom0 is CentOS 5.3 as well), but when I shutdown the domU, this happens: cx88[0]: mpeg risc op code error cx88[0]: mpeg - dma channel status dump cx88[0]: cmds: initial risc: 0xffffffff cx88[0]: cmds: cdt base : 0xffffffff cx88[0]: cmds: cdt size : 0xffffffff cx88[0]: cmds: iq base : 0xffffffff cx88[0]: cmds: iq size : 0xffffffff cx88[0]: cmds: risc pc : 0xffffffff cx88[0]: cmds: iq wr ptr : 0xffffffff cx88[0]: cmds: iq rd ptr : 0xffffffff cx88[0]: cmds: cdt current : 0xffffffff cx88[0]: cmds: pci target : 0xffffffff cx88[0]: cmds: line / byte : 0xffffffff cx88[0]: risc0: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: risc1: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: risc2: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: risc3: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 0: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 1: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 2: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 3: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 4: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 5: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 6: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 7: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 8: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq 9: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq a: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq b: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq c: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq d: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq e: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: iq f: 0xffffffff [ INVALID sol eol irq2 irq1 23 22 21 20 19 18 cnt1 cnt0 resync 14 13 12 count=4095 ] cx88[0]: fifo: 0x00186400 -> 0x187400 cx88[0]: ctrl: 0x001807c0 -> 0x180820 cx88[0]: ptr1_reg: 0xffffffff cx88[0]: ptr2_reg: 0xffffffff cx88[0]: cnt1_reg: 0xffffffff cx88[0]: cnt2_reg: 0xffffffff This loops forever eating every available cpu cycle. The dom0 becomes unusably slow until I manually destroy the domU. The domU runs 2.6.18-128.1.10.el5xen with video4linux-kmdl-2.6.18-128.1.10.el5xen-20090415-88.0.4.el5 (there are no video4linux-kmdls for the latest kernel yet). Manually unloading the modules before shutting down has no effect. Without video4linux-kmdl installed, everything works fine. I hope you can help me. Regards, Chris

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Centos virsh - add a physical device
by For＠ll 30 Sep '09

30 Sep '09

Hi, If I create a guest which uses (hvm) can I add access to physical device like cdrom? Regards, For@ll

5 10

Resizing disks for VMs
by Dennis J. 28 Sep '09

28 Sep '09

Hi, Is there a way to make a PV xen guest aware of a size change of the host disk? In my case I'm talking about a Centos 5.3 host using logical volumes as storage for the guests and the guests running Centos 5.3 and LVM too. What I'm trying to accomplish is to resize the logical volume for the guest by adding a few gigs and then make the guest see this change without requiring a reboot. Is this possible maybe using some kind of bus rescan in the guest? Regards, Dennis

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IP aliases of CentOS Guests not accessible running 2.6.18-164.el5xen
by Devraj Mukherjee 28 Sep '09

28 Sep '09

Hi all, First of all I am posting this on two lists for a reason, because the issue being reported by me could be because of a change delivered by a Kernel update or due to Xen. I have recently managed to update all Xen Guest domains running CentOS 5.3 to the latest bunch of updates + Kernel. My Xen host also runs the same CentOS 5.3 updated to all recent packages. The Guest images in concern had IP aliases assigned to them. Everything worked until I ran the updates and restarted. Since I have restarted the aliased IP addresses are no longer accessible from the outside world, they can still be accessed from all machines (guest virtual machines) in the subnet (ping, services like http). I have removed all firewall rules to test if that would have effected it without any change (any the fact that I can access them within the subnet proves its not the firewall). Is there anything special I have to do to enable aliasing? May be this is a Xen issue? I am suspecting the Xen host, but not sure how to go about proving this. Any information would be greatly appreciated. My Guests do run fail2ban (delivered via atrpms) and iptables (allowing only HTTP, HTTPS and SSH) connections. PS for obvious reasons I am not posting IP addresses and routes etc first up, I can make that information available if required. -- "The secret impresses no-one, the trick you use it for is everything" - Alfred Borden (The Prestiege)

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Re: [CentOS-virt] Domain0 with Kernel 2.6.18-92.1.22.el5xen fails to boot Guests with Kernel 2.6.18-164.el5xen
by Christopher G. Stach II 27 Sep '09

27 Sep '09

----- "Devraj Mukherjee" <devraj(a)gmail.com> wrote: > Hi all, > > I am in a bit of a fix here, I have several Guests paravirtualized > running on a Dom0 that is currently running the 2.6.18-92.1.22.el5xen > Kernel. All my guests (administered by different people) have > subsequently been updated to later versions of the kernel (namely > 2.6.18-164.el5xen or 2.6.18-128.4.1.el5xen). [...] > I restarted a Guest that's now trying to boot with the > 2.6.18-164.el5xen Kernel and it spits out messages like > XENBUS: Waiting for devices to initialise: 295s...290s... > > and eventually reboots. IIRC, there were changes to the block back-/frontend drivers a while back, but that probably wouldn't do this. I would first look to make sure that your dom0 Xen daemons are in good condition. Occasionally, they will die or stop working. Watching the logs when you start your guest may give you some clues as to what dom0 may be hanging on. Restarting xend and/or xenconsoled (typically when your guest can't get a console or when ``xm console'' mysteriously doesn't work) may help. Anyway, you should update your dom0 kernel. That's pretty old. :) -- Christopher G. Stach II

1 0

xen & iSCSI
by Daniel De Marco 24 Sep '09

24 Sep '09

Hi, I'm setting up xen (on centos 5.3) and I'm facing a weird performance issue with iSCSI. I attach the iSCSI targets to dom0 and if I use them from dom0 I obtain good performance with simple dd tests (~100MB/s both reading and writing). I then use the block devices for the domU and if I repeat the same dd test from within the domU the write performace is still good (~100MB/s), but the read performance is cut in half (~55MB/s). I tried changing several parameters like read_ahead and such, but I can not obtain a good read performance in the domU. Any idea? Thanks, Daniel.

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Writing iptables for inbound connections with libvirt
by carlopmart 16 Sep '09

16 Sep '09

Hi all, I have installed a CentOS 5.3 x86_64 server with kvm and libvirt to do some tests for future virtualized deployments. My environment: eth0 --> 172.25.50.1/24 ("public" host ip) virbr0 ---> 192.168.122.1/24 (natted interface installed by libvirt) virbr1 ---> 172.26.50.0/24 (internal virtualized network, whithout physical interface binded) Between 192.168.122.0/24 network and 172.26.50.0/24 network I have installed a virtual firewall. So to reach 172.26.50.0/24 network, all connections needs to come from 192.168.122.0/24 network. I need to insert some iptables rules to allow access to some services installed on 172.26.50.0/24 network like smtp,http,ftp, etc. How can I configure libvirt to forward and nat these services coming from 172.25.50.0/24 network to a specific IP under 192.168.122.0/24 network?? Or do I need to use /etc/sysconfig/iptables configuration?? Some examples, please??. Many thanks. -- CL Martinez carlopmart {at} gmail {d0t} com

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virt September 2009