Re: [CentOS-virt] Best practices for LVM and virtualization
Mathieu Baudier wrote: 3. On both host and guest This is what I always use and recommend. It doesn't have any side effects with modern software versions, except with layered Thanks! I have tried this, but I don't see how to grow the guest file system without restarting the guest: - if I grow the underlying logical volume on the host, the guest still see the hard drive with the old size (checking with fdisk) - if I would add additional logical volumes (host) / drives (guest) in order to add them to the guest volume group, I will have to restart the guest I am using virtio disks. Is there a command so that the guest notices that its harddrive has grown? Is there a way to add new drives without restarting the guest? yes, you can add / remove disks to a VM without restarting the guest. look at the xm block-attach / block-detach commands ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Best practices for LVM and virtualization
yes, you can add / remove disks to a VM without restarting the guest. look at the xm block-attach / block-detach commands My understanding is that xm is Xen specific (I'm using Qemu/KVM) I tried with virsh: virsh # attach-disk 6 /dev/mapper/vg_alma_fast-lv_test_virtlvm2 vdb Disk attached successfully virsh # dumpxml 6 domain type='kvm' id='6' ... devices emulator/usr/libexec/qemu-kvm/emulator ... disk type='block' device='disk' source dev='/dev/mapper/vg_alma_fast-lv_test_virtlvm'/ target dev='vda' bus='virtio'/ /disk disk type='block' device='disk' driver name='phy'/ source dev='/dev/mapper/vg_alma_fast-lv_test_virtlvm2'/ target dev='vdb' bus='virtio'/ /disk ... /devices /domain But I still cannot see the disk using fdisk: there is no /dev/vdb. Please note that I'm testing with a minimal CentOS installation (without even the Base group). So maybe it lacks some required deamons (there is no ACPI deamon for exmaple). I will try again with an install including the Base group. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Best practices for LVM and virtualization
Mathieu Baudier wrote: yes, you can add / remove disks to a VM without restarting the guest. look at the xm block-attach / block-detach commands My understanding is that xm is Xen specific (I'm using Qemu/KVM) I tried with virsh: virsh # attach-disk 6 /dev/mapper/vg_alma_fast-lv_test_virtlvm2 vdb Disk attached successfully virsh # dumpxml 6 domain type='kvm' id='6' ... devices emulator/usr/libexec/qemu-kvm/emulator ... disk type='block' device='disk' source dev='/dev/mapper/vg_alma_fast-lv_test_virtlvm'/ target dev='vda' bus='virtio'/ /disk disk type='block' device='disk' driver name='phy'/ source dev='/dev/mapper/vg_alma_fast-lv_test_virtlvm2'/ target dev='vdb' bus='virtio'/ /disk ... /devices /domain But I still cannot see the disk using fdisk: there is no /dev/vdb. You also need to tell the guest that a new device exists... Unless it (the guest) has some hotswap abilities ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Best practices for LVM and virtualization
You also need to tell the guest that a new device exists... Unless it (the guest) has some hotswap abilities Do you know how I can do that? I reinstalled the guest (CentOS 5.4 x86_64, just as the host) with the default non-desktop groups, but it still doesn't see when I attach a disk. I also try to disable SELinux, to no effect. I've googling intensively around the concept of hotplug, hotswap, PCI, HAL, etc. in relation to virsh/KVM/virtio but withotu success. On the guest, lspci only shows on drive (the initial one I guess): [r...@localhost ~]# lspci 00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02) 00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II] 00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II] 00:01.2 USB Controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01) 00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03) 00:02.0 VGA compatible controller: Cirrus Logic GD 5446 00:03.0 Ethernet controller: Qumranet, Inc. Virtio network device 00:04.0 SCSI storage controller: Qumranet, Inc. Virtio block device 00:05.0 RAM memory: Qumranet, Inc. Virtio memory balloon ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Best practices for LVM and virtualization
Mathieu Baudier wrote: You also need to tell the guest that a new device exists... Unless it (the guest) has some hotswap abilities Do you know how I can do that? something along echo - - - /sys/class/scsi_host/hostX/scan // yes, the - must be there ! might help I reinstalled the guest (CentOS 5.4 x86_64, just as the host) with the default non-desktop groups, but it still doesn't see when I attach a disk. I also try to disable SELinux, to no effect. I've googling intensively around the concept of hotplug, hotswap, PCI, HAL, etc. in relation to virsh/KVM/virtio but withotu success. On the guest, lspci only shows on drive (the initial one I guess): [r...@localhost ~]# lspci 00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02) 00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II] 00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II] 00:01.2 USB Controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01) 00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03) 00:02.0 VGA compatible controller: Cirrus Logic GD 5446 00:03.0 Ethernet controller: Qumranet, Inc. Virtio network device 00:04.0 SCSI storage controller: Qumranet, Inc. Virtio block device 00:05.0 RAM memory: Qumranet, Inc. Virtio memory balloon ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt -- Manuel Wolfshant linux registered user #131416 IT managerNoBug Consulting SRL A: Yes. Q: Are you sure? A: Because it reverses the logical flow of conversation. Q: Why is top posting frowned upon? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Best practices for LVM and virtualization
something along echo - - - /sys/class/scsi_host/hostX/scan // yes, the - must be there ! Unfortunately there is nothing under scsi: [r...@localhost ~]# ll /sys/class/scsi_* /sys/class/scsi_device: total 0 /sys/class/scsi_disk: total 0 /sys/class/scsi_host: total 0 I also tried kudzu (http://linux.die.net/man/8/kudzu), but it still shows only the original drive: [r...@localhost ~]# kudzu [r...@localhost ~]# kudzu -p ... - class: HD bus: VIRTIO detached: 0 device: vda driver: virtio_blk desc: Virtio Block Device - ... While looking around I found this comment (in a bug not directly related): Yaniv Kaul 2009-05-19 06:53:14 EDT Hot-add is not supported for RHEV 2.1. https://bugzilla.redhat.com/show_bug.cgi?id=501468#c1 So maybe it actually cannot work? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
