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KVM guest on a specific disk
by rewing 09 Dec '09

09 Dec '09

I'm deploying my KVM virtualization and I have this question. To get my guest os best performance I would like to install my OS from CD ROM while booting in a saperate disk, say /dev/sda4 then in host os I mount /dev/sda4 as /mnt/vm. So I can install a guest OS by virt-install with synax --import, right? I didn't give it a try yet so I'd like to know if other people have done it successfully. Will this let guest os best performance because it has its own disk rather than just a image file? and will it ocuppy the host running resources less? Rewing

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Re: [CentOS-virt] virt-install failed while install windows2003 guest
by rewing 09 Dec '09

09 Dec '09

Hi,All I've solve this problem by doing a chcon --reference=/var/lib/libvirt/images /vm this solve selinux block kvm from accessing disk image outside of /var/lib/libvirt/images Thanks 2009-12-09 rewing 发件人： centos-virt-request 发送时间： 2009-12-09 00:57:19 收件人： centos-virt 抄送：主题： CentOS-virt Digest, Vol 28, Issue 9 Send CentOS-virt mailing list submissions to centos-virt(a)centos.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.centos.org/mailman/listinfo/centos-virt or, via email, send a message with subject or body 'help' to centos-virt-request(a)centos.org You can reach the person managing the list at centos-virt-owner(a)centos.org When replying, please edit your Subject line so it is more specific than "Re: Contents of CentOS-virt digest..." Today's Topics: 1. virt-install failed while install windows2003 guest (rewing) 2. Re: virt-install failed while install windows2003 guest (Markus Falb) 3. Re: virt-install failed while install windows2003 guest (Tait Clarridge) ---------------------------------------------------------------------- Message: 1 Date: Tue, 8 Dec 2009 16:58:56 +0800 From: "rewing" <rewing(a)howfortune.com> Subject: [CentOS-virt] virt-install failed while install windows2003 guest To: "centos-virt" <centos-virt(a)centos.org> Message-ID: <200912081658540620074(a)howfortune.com> Content-Type: text/plain; charset="us-ascii" Here's the procedure: # qemu-img -f qcow2 /vm/win2k3.img 8G # virt-install --connect qemu:///system -n win2k3 -r 512 --vcpus=1 -c /home/temp/win2003sp2ins.iso -f /vm/win2k3.img -s 4 --network=bridge:br0 --mac=00:ff:ff:ff:58:58 --noautoconsole --vnc --os-type=windows --os-variant=win2k3 --hvm --accelerate And I get error as below: Starting install... internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img Domain installation may not have been successful. If it was, you can restart your domain by running 'virsh start win2k3'; otherwise, please restart your installation. ERROR internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img Traceback (most recent call last): File "/usr/sbin/virt-install", line 861, in ? main() File "/usr/sbin/virt-install", line 759, in main start_time, guest.start_install) File "/usr/sbin/virt-install", line 814, in do_install dom = install_func(conscb, progresscb, wait=(not wait)) File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 541, in start_install return self._do_install(consolecb, meter, removeOld, wait) File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 633, in _do_install self.domain = self.conn.createLinux(install_xml, 0) File "/usr/lib64/python2.4/site-packages/libvirt.py", line 974, in createLinux if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self) libvirtError: internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img any idea? 2009-12-08 rewing -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.centos.org/pipermail/centos-virt/attachments/20091208/55c24500… ------------------------------ Message: 2 Date: Tue, 8 Dec 2009 12:41:34 +0100 From: Markus Falb <markus.falb(a)fasel.at> Subject: Re: [CentOS-virt] virt-install failed while install windows2003 guest To: Discussion about the virtualization on CentOS <centos-virt(a)centos.org> Message-ID: <7FEF197D-7025-4E95-87DB-72AE50CEFA3E(a)fasel.at> Content-Type: text/plain; charset="us-ascii" On 8 Dec 2009, at 09:58, rewing wrote: > libvirtError: internal error unable to start guest: qemu: could not > open disk image /vm/win2k3.img Do you have selinux enabled ? As far as I know the location for images is restricted to /var/lib/libvirt/images by default. -- Markus -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.centos.org/pipermail/centos-virt/attachments/20091208/ac8640d6… ------------------------------ Message: 3 Date: Tue, 08 Dec 2009 09:11:02 -0500 From: Tait Clarridge <tait(a)clarridge.ca> Subject: Re: [CentOS-virt] virt-install failed while install windows2003 guest To: Discussion about the virtualization on CentOS <centos-virt(a)centos.org> Message-ID: <1260281462.2495.1.camel(a)taiterltp.int.interactivemedia.com> Content-Type: text/plain; charset="utf-8" On Tue, 2009-12-08 at 12:41 +0100, Markus Falb wrote: > > On 8 Dec 2009, at 09:58, rewing wrote: > > libvirtError: internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img > > > Do you have selinux enabled ? As far as I know the location for images > is restricted to /var/lib/libvirt/images by default. > > -- Or does the actual disk image exist at /vm/win2k3.img with r/w access to whoever is running the virt-install command? Does the /vm directory exist and does the user have permissions to access it? -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: This is a digitally signed message part Url : http://lists.centos.org/pipermail/centos-virt/attachments/20091208/79487930… ------------------------------ _______________________________________________ CentOS-virt mailing list CentOS-virt(a)centos.org http://lists.centos.org/mailman/listinfo/centos-virt End of CentOS-virt Digest, Vol 28, Issue 9 ******************************************

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virt-install failed while install windows2003 guest
by rewing 08 Dec '09

08 Dec '09

Here's the procedure: # qemu-img -f qcow2 /vm/win2k3.img 8G # virt-install --connect qemu:///system -n win2k3 -r 512 --vcpus=1 -c /home/temp/win2003sp2ins.iso -f /vm/win2k3.img -s 4 --network=bridge:br0 --mac=00:ff:ff:ff:58:58 --noautoconsole --vnc --os-type=windows --os-variant=win2k3 --hvm --accelerate And I get error as below: Starting install... internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img Domain installation may not have been successful. If it was, you can restart your domain by running 'virsh start win2k3'; otherwise, please restart your installation. ERROR internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img Traceback (most recent call last): File "/usr/sbin/virt-install", line 861, in ? main() File "/usr/sbin/virt-install", line 759, in main start_time, guest.start_install) File "/usr/sbin/virt-install", line 814, in do_install dom = install_func(conscb, progresscb, wait=(not wait)) File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 541, in start_install return self._do_install(consolecb, meter, removeOld, wait) File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 633, in _do_install self.domain = self.conn.createLinux(install_xml, 0) File "/usr/lib64/python2.4/site-packages/libvirt.py", line 974, in createLinux if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self) libvirtError: internal error unable to start guest: qemu: could not open disk image /vm/win2k3.img any idea? 2009-12-08 rewing

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S3 (Suspend to Disk) with XEN
by Yukio Yamaishi 07 Dec '09

07 Dec '09

Hi All, I have a 5.4 box and testing xen 3.4 on kernel-xen-2.6.18-164.6.1.el5. As you know, there are no enough configuration to do "Suspend to Disk" of the .config of the kernel-xen-2.6.18-164.6.1.el5. # Power management options (ACPI, APM) # CONFIG_PM=y Then, I tied to get the kernel-2.6.18-164.6.1.el5.src.rpm, installed that. #pwd /usr/src/redhat/BUILD/kernel-2.6.18/linux-2.6.18.i686 #cp configs/kernel-2.6.18-i686-xen.config .config #make menuconfig Power management options (ACPI, APM) ---> ACPI (Advanced Configuration and Power Interface) Support ---> │ │ │ │ CPU Frequency scaling ---> │ │ There are no menu which likes "Legacy Power Management API". How can I add the options to enable the Supend to Disk? Yukio

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Re: [CentOS-virt] Slightly OT: FakeRaid or Software Raid
by Christopher G. Stach II 04 Dec '09

04 Dec '09

----- "Grant McWilliams" <grantmasterflash(a)gmail.com> wrote: > On Wed, Dec 2, 2009 at 9:48 PM, Christopher G. Stach II < > cgs(a)ldsys.net > wrote: > > ----- "Grant McWilliams" < grantmasterflash(a)gmail.com > wrote: > > > a RAID 10 (or 0+1) will never reach the write... performance of > > a RAID-5. > > (*cough* If you keep the number of disks constant or the amount of > usable space? "Things working" tends to trump CapEx, despite the > associated pain, so I will go with "amount of usable space.") > > No. > > -- > Christopher G. Stach II > > Nice quality reading. I like theories as much as the next person but > I'm wondering if the Toms Hardware guys are on crack or you disapprove > of their testing methods. > > http://www.tomshardware.com/reviews/external-raid-storage,1922-9.html They used a constant number of disks to compare two different hardware implementations, not to compare RAID 5 vs. RAID 10. They got the expected ~50% improvement from the extra stripe segment in RAID 5 with a serial access pattern. Unfortunately, that's neither real world use nor the typical way you would fulfill requirements. If you read ahead to the following pages, you have a nice comparison of random access patterns and RAID 10 coming out ahead (with one less stripe segment and a lot less risk): http://www.tomshardware.com/reviews/external-raid-storage,1922-11.html http://www.tomshardware.com/reviews/external-raid-storage,1922-12.html -- Christopher G. Stach II

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Re: [CentOS-virt] Slightly OT: FakeRaid or Software Raid
by Christopher G. Stach II 03 Dec '09

03 Dec '09

----- "Ben M." <centos(a)rivint.com> wrote: > I have had great luck with nvidia fakeraid on RAID1, but I see there > are > preferences for software raid. I have very little hands on with full > Linux software RAID and that was about 14 years ago. MD RAID. I'd even opt for MD RAID over a lot of hardware implementations. This writeup summarizes a bit of why: http://jeremy.zawodny.com/blog/archives/008696.html Hardware RAID's performance is obviously going to be better, but it's only worth it if you *need* it (more than ~8 disks, parity). If you're just doing RAID 0, 1, or 10 in a single box and you're not pushing it to its limits as a DB server or benchmarking and going over it with a magnifying glass, you probably won't notice a difference in performance. I'll take fewer moving parts and portability. As someone already said, dmraid is done in software, too. "Fakeraid" is basically the same as MD RAID, but with an extra piece of hardware and extra logic bits to fail. -- Christopher G. Stach II

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Re: [CentOS-virt] Slightly OT: FakeRaid or Software Raid
by Christopher G. Stach II 03 Dec '09

03 Dec '09

----- "Grant McWilliams" <grantmasterflash(a)gmail.com> wrote: > RAID 5 is faster than RAID 10 for reads and writes. *Serial* reads and writes. That is not the access pattern that you will have in most virtualization hosts. > What wasn't in the test (but is in others that they've done) is RAID > 6. I'm not sure I'm sold on it because it gives us about the same > level of redundancy as RAID 10 but with less performance than RAID 5. > Theoretically it would get soundly trounced by RAID 10 on IOs and > maybe be slower on r/w transfer as well. RAID 6 is pretty slow, but you can stripe them as RAID 60. If you need that kind of fault tolerance, the performance hit is negligible. On high volume boxes with low performance requirements, say NLS on an 8-12 bay 2U or 3U machine, I use RAID 6 with one hot spare. -- Christopher G. Stach II

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Re: [CentOS-virt] Slightly OT: FakeRaid or Software Raid
by Christopher G. Stach II 03 Dec '09

03 Dec '09

----- "Grant McWilliams" <grantmasterflash(a)gmail.com> wrote: > Interesting thoughts on raid5 although I doubt many would agree. That's okay. We all have our off days... Here's some quality reading: http://blogs.sun.com/bonwick/entry/raid_z http://www.cyberciti.biz/tips/raid5-vs-raid-10-safety-performance.html http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt http://www.miracleas.com/BAARF/1.Millsap2000.01.03-RAID5.pdf http://www.codinghorror.com/blog/archives/001233.html http://web.ivy.net/carton/rant/ml/raid-raid5writehole-0.html Maybe you are thinking of RAID 6. > I don't see how the drive type has ANYTHING to do with the RAID > level. IOPS, bit error ratio, bus speed, and spindle speed tend to factor in and are usually governed by the drive type. (The BER is very important for how often you can expect the data elves come out and chew on your data during RAID 5 rebuilds.) You will use those numbers to calculate the number of stripe segments, controllers, and disks. Combine that with the controller's local bus, number of necessary controllers, host bus, budget, and other business requirements and you have a RAID type. > a RAID 10 (or 0+1) will never reach the write... performance of > a RAID-5. (*cough* If you keep the number of disks constant or the amount of usable space? "Things working" tends to trump CapEx, despite the associated pain, so I will go with "amount of usable space.") No. -- Christopher G. Stach II

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Re: [CentOS-virt] Slightly OT: FakeRaid or Software Raid
by Christopher G. Stach II 02 Dec '09

02 Dec '09

----- "Grant McWilliams" <grantmasterflash(a)gmail.com> wrote: > He had a two drive RAID 1 drives and at least one of them failed but > he didn't have any notification software set up to let him know that > it had failed. And since that's the case he didn't know if both drives > had failed or not. I wonder why he things software RAID would be a) > more reliable b) fix itself magically without telling him. He never > did say if he was able to use the second disk. I have 75 machines with > 3ware controllers and on the very rare occasion that a controller > fails you plug in another one and boot up. I have a pile of various RAID controllers from 3ware, Promise, LSI, the utter garbage that older PERCs were, etc. that have pissed me off by randomly dropping disks, not rebuilding or detecting its own disks, hanging, etc. and very importantly, not allowing me to move disks between machines. That being said, I still have two 3ware cards and some LSI that are fine, but most of my arrays are software. Anecdotal evidence aside, unless you know what kind of performance you need, you have usage metrics, and you know how to benchmark properly, you probably don't need the risk and marginal performance improvement of some extra hardware. (This was originally about fakeraid, wasn't it?) > I don't use software RAID in any sort of production environment unless > it's RAID 0 and I don't care about the data at all. I've also tested > the speed between Hardware and Software RAID 5 and no matter how many > CPUs you throw at it the hardware will win. I don't allow RAID 5, so the increased checksum processing performance doesn't have any bearing on my choices. :) > Even in the case when a > 3ware RAID controller only has one drive plugged in it will beat a > single drive plugged into the motherboard if applications are > requesting dissimilar data. One stream from an MD0 RAID 0 will be as > fast as one stream from a Hardware RAID 0. Multiple streams of > dissimilar data will be much faster on the Hardware RAID controller > due to controller caching. True. That probably falls under be the aforementioned "need". :) You can't beat the performance of a cache, although the Linux filesystem cache will perform reasonably well. If you're using something like an ACID compliant DB, you'll want the battery backed hardware cache for any sizable amount of I/O. Discussing performance without discussing benchmark methodology is annoying and often useless, but if you want to go down that route... (Also, your use case is contrary to your storage design. You would use RAID 0 for serial access and something parallel for random access. Yes, a Ford Explorer doesn't hug corners at 120 mph.) -- Christopher G. Stach II

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KVM Support for Windows Server 2003 32 bit ready for production?
by Neil Aggarwal 02 Dec '09

02 Dec '09

Hello: I am wondering if KVM is ready for production for running a Windows Server 2003 32 bit guest. According to the RHEL 5.4 virtualization guide, there is supposed to be a virtio-win yum package, but that was not released. Instead, it looks like that is only available for RHN subscribers. Also, I saw this posting on the CentOS list: --- Quoted from CL Martinez There are freely redistributable, but still they aren't published by upstream. You can use these instead: http://www.linux-kvm.com/content/windows-binary-virtio-drivers-finally-relea sed, but there are a lot of problems with any windows 64 bits. And another problem, a big really, is that you can¡t install a windows kvm guest directly to a virtio disk. First you need to install to an ide disk, after generate a virtio disk and attach to win guest, install the virtio driver and last remove ide drive ... very very ugly. ---- End Quote That seems to imply things are still not ready for production use. Any opinions? Thanks, Neil -- Neil Aggarwal, (281)846-8957, http://UnmeteredVPS.net CentOS 5.4 VPS with unmetered bandwidth only $25/month! No overage charges, 7 day free trial, Google Checkout accepted

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