For a customer Proof of Concept - demonstrating the benefits of Oracle Fusion Middleware on Exalogic Virtual - we decided to build a custom base template. All vServers created by using this custom base template enable some customer specific configuration settings, activation of additional services and yields flexibility for the file-system layout.
We decided to use Logical Volume Management LVM2 to achieve the goal of file-system flexibility. This can easily be implemented, as the Base vServer Template, delivered by Oracle, already has all the necessary rpm's installed. The Default Gemini and Navstar vServer Templates come with a fixed partition and file-system layout. To keep a simple layout we went for one logical volume for the root file-system and another volume for swap. By using an ext3 file-system on top of the logical volume for root we are now able to re-size it as needed during normal operation. So whenever logs are filling up /var, or pre-req checks fail due to a lack of space in /tmp we can easily correct this.
In this first blog I will describe how to build a vServer using LVM2. As I said before, for the PoC we planned to use this vServer as a new custom base template. In a second blog post I will show the steps needed to create a vServer template out of this vServer.
This is very similar to what my colleague Andrew Hopkinson has already blogged about here
, but needs a few extra steps because of the LVM2 usage.
Here is what I did:
Using EMOC I created a custom vServer Type with:
- Memmory Size: 4GB
- Storage Size: >=10GB
- vCPU's: 2
Using EMOC I created a vServer:
- In the create vServer wizard I:
- Selected the Default Navstar vServer Template.
- Chose the vServer Type created above.
- Configured EoIB client and shared-storage network.
I used ssh to login to newly created vServer
- First of all I inspected the original partition setup and file system usage.
[root@lvm-tvm ~]# fdisk -l /dev/xvda Disk /dev/xvda: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/xvda1 * 1 13 104391 83 Linux /dev/xvda2 14 615 4835565 83 Linux /dev/xvda3 616 679 514080 82 Linux swap / Solaris [root@lvm-tvm ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/xvda2 4687500 3453556 1040524 77% / /dev/xvda1 101086 21727 74140 23% /boot tmpfs 2024748 0 2024748 0% /dev/shm
swapoff /dev/xvda3
fdisk /dev/xvda <<EOF d 3 n p 3 t 3 8e w EOF
[root@lvm-tvm ~]# fdisk -l /dev/xvda Disk /dev/xvda: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/xvda1 * 1 13 104391 83 Linux /dev/xvda2 14 615 4835565 83 Linux /dev/xvda3 616 1305 5542425 8e Linux LVM
[root@lvm-tvm ~]# partprobe /dev/xvda
[root@lvm-tvm ~]# pvcreate /dev/xvda3 WARNING: swap signature detected on /dev/xvda3. Wipe it? [y/n] y Wiping swap signature on /dev/xvda3. Physical volume "/dev/xvda3" successfully created
vgcreate VolGroup00 /dev/xvda3 lvcreate -L 1G -n swapVol VolGroup00 lvcreate -L 4G -n rootVol VolGroup00 mkfs.ext3 -L/root /dev/mapper/VolGroup00-rootVol mkdir /mnt/rootfs mount -t ext3 /dev/mapper/VolGroup00-rootVol /mnt/rootfs mkdir /mnt/rootfs/boot mount -t ext3 /dev/xvda1 /mnt/rootfs/boot
[root@lvm-tvm ~]# find / -xdev | cpio -pmd /mnt/rootfs
mount -o bind /dev /mnt/rootfs/dev chroot /mnt/rootfs mount -t proc /proc /proc mount -t sysfs /sys /sys
vi /etc/fstab LABEL=/root / ext3 defaults 1 1 LABEL=/boot /boot ext3 defaults 1 2 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 LABEL=swap swap swap defaults 0 0 cd /boot mv initrd-2.6.32-200.21.2.el5uek.img initrd-2.6.32-200.21.2.el5uek.img.old mkinitrd -v --builtin=ehci-hcd --builtin=ohci-hcd --builtin=uhci-hcd initrd-$(uname -r).img $(uname -r) vi /boot/grub/grub.conf title Oracle Linux Server (2.6.32-200.21.2.el5uek) root (hd0,0) kernel /vmlinuz-2.6.32-200.21.2.el5uek ro root=LABEL=/root rhgb tsc=reliable nohpet nopmtimer hda=noprobe hdb=noprobe ide0=noprobe numa=off console=tty0 console=ttyS0,19200n8 initrd /initrd-2.6.32-200.21.2.el5uek.img reboot
Reuse now free space from former root partition xvda2.
- Use ssh to login to lvm-tvm again.
- Inspect current partition and file-system layout.
[root@lvm-tvm ~]# fdisk -l /dev/xvda Disk /dev/xvda: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/xvda1 * 1 13 104391 83 Linux /dev/xvda2 14 615 4835565 83 Linux /dev/xvda3 616 1305 5542425 8e Linux LVM [root@lvm-tvm ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup00-rootVol 4128448 3521732 397004 90% / /dev/xvda1 101086 25356 70511 27% /boot tmpfs 2024748 0 2024748 0% /dev/shm
[root@lvm-tvm ~]# vgextend VolGroup00 /dev/xvda2 No physical volume label read from /dev/xvda2 Physical volume "/dev/xvda2" successfully created Volume group "VolGroup00" successfully extended
[root@lvm-tvm ~]# lvextend -L+2.89G /dev/VolGroup00/rootVol Rounding up size to full physical extent 2.89 GB Extending logical volume rootVol to 6.89 GB Logical volume rootVol successfully resized [root@lvm-tvm ~]# lvextend -L+2G /dev/VolGroup00/swapVol Extending logical volume swapVol to 3.00 GB Logical volume swapVol successfully resized
[root@lvm-tvm ~]# resize2fs /dev/VolGroup00/rootVol 6G resize2fs 1.39 (29-May-2006) Filesystem at /dev/VolGroup00/rootVol is mounted on /; on-line resizing required Performing an on-line resize of /dev/VolGroup00/rootVol to 1572864 (4k) blocks. The filesystem on /dev/VolGroup00/rootVol is now 1572864 blocks long.
[root@lvm-tvm ~]# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup00-rootVol 6192704 3521756 2356404 60% / /dev/xvda1 101086 25356 70511 27% /boot tmpfs 2024748 0 2024748 0% /dev/shm
[root@lvm-tvm ~]# mkswap -L swap /dev/VolGroup00/swapVol Setting up swapspace version 1, size = 3221221 kB LABEL=swap, no uuid [root@lvm-tvm ~]# swapon /dev/VolGroup00/swapVol
[root@lvm-tvm ~]# free -m total used free shared buffers cached Mem: 3954 479 3475 0 42 116 -/+ buffers/cache: 320 3634 Swap: 3071 0 3071
we are done!