Cumin

From Wikked

Cumin is Mark's (VM host) home server.

• IP address: 192.168.20.20

Contents 1 Storage layout 1.1 Paritioning 1.2 LVM 2 VMs 3 Configuration 3.1 X.org

Storage layout

Paritioning

Partitioning of /dev/sda, /dev/sdb, /dev/sdc (all equal):

Model: ATA ST2000DL003-9VT1 (scsi)
Disk /dev/sda: 3907029168s
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start      End          Size         File system     Name       Flags
 1      2048s      391167s      389120s                      UEFI BOOT  bios_grub
 2      391168s    878591s      487424s      ext2            boot       raid
 3      878592s    39940095s    39061504s    btrfs           root
 4      39940096s  47753215s    7813120s     linux-swap(v1)  swap
 5      47753216s  3907028991s  3859275776s                  raid5      raid

• /dev/sdX1 are UEFI boot partitions
• /dev/sdX2 is /dev/md0, a 3-disk RAID1 array for /boot
• /dev/sdX3 is a 3-device BTRFS RAID1 file system for /
• /dev/sdX4 are 3 separate Linux swap partitions
• /dev/sdX5 is a 3-device MD RAID5 array (/dev/md1), the single LVM PV for VG raid5

LVM

LVM VG raid5 (3.6 TB) has the following LVs:

  LV            VG    Attr   LSize   Origin Snap%  Move Log Copy%  Convert
  backups       raid5 -wi-ao 600.00g                                      
  home          raid5 -wi-ao 279.39g                                      
  media         raid5 -wi-ao 931.32g                                      
  rootfs-backup raid5 -wi-a-  20.00g                                      
  virt          raid5 -wi-ao  93.13g 

They are mounted as follows:

/dev/sda3 on / type btrfs (rw,compress)
/dev/md0 on /boot type ext2 (rw)
/dev/mapper/raid5-backups on /backups type btrfs (rw,compress)
/dev/mapper/raid5-home on /home type ext4 (rw,user_xattr,acl)
/dev/mapper/raid5-virt on /var/lib/virt type ext4 (rw)
/dev/mapper/raid5-media on /srv/media type ext4 (rw,user_xattr,acl)

EXT4 file system rootfs-backup is only mounted during a daily rsync from the (experimental) BTRFS root file system, using BTRFS snapshots.

VMs

chili (192.168.20.21) 

package building for Maverick

$ sudo vmbuilder kvm ubuntu -d /var/lib/virt/images/chili -t /var/lib/virt/tmp -o --suite maverick --flavour virtual --arch amd64 -m 1024 --cpus 2 --rootsize 10000 --libvirt qemu:///system --ip 192.168.20.21 --gw 192.168.20.1 --hostname chili --bridge br0.2 --addpkg openssh-server --user mark --name "Mark Bergsma" --mirror http://nl.archive.ubuntu.com/ubuntu

But this had slow I/O. Initially it wasn't using cache="writeback", but this didn't improve all that much either.

Enabling VirtIO helped a lot. Why wasn't this on by default? XML config bits:

    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='writeback'/>
      <source file='/var/lib/virt/images/chili/tmpwpu2uK.qcow2'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </disk>

To fix:

• Serial console output instead of VNC by default

Configuration

X.org

X works fine without a configuration, but does not offer a 1080x1920 24 Hz video mode this way. This is fixed by using the following as /etc/X11/xorg.conf:

Section "Device"
        Identifier "Intel HD Graphics"
        Driver "intel"
        BusID "PCI:0:2:0"

        Option "monitor-HDMI3" "Samsung LE40C630"
EndSection

Section "Monitor"
        Identifier "Samsung LE40C630"

        #Modeline "1920x1080"x60.0  148.50  1920 2008 2052 2200  1080 1084 1089 1125 +hsync +vsync      
        ModeLine "1920x1080p24"  74.16  1920 2558 2602 2750  1080 1084 1089 1125  +HSync +VSync
        ModeLine "1920x1080p50"  148.50  1920 2448 2496 2640  1080 1084 1089 1125  +HSync +VSync
EndSection