How to resize the root partition inside a VM image running on ODA (Oracle Database Appliance)
In this article we are using the resize2fs program. It will resize ext2, ext3 file systems.
This article is not applicable if you want resize an ext4 partition as resize4fs & e4fsck tools are needed
In this example we have a small Oracle Enterprise Linux image
# ls -slh /OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/*.img
15G -rw-r--r-- 1 root root 14G Jan 30 01:44 /OVS/Repositories/odarepo2/VirtualMachines/oel_5/oel_5.8.img
Inside the image we have the following partitions:
Device Boot Start End Blocks Id System
/dev/xvda1 * 1 13 104391 83 Linux
/dev/xvda2 14 1305 10377990 83 Linux
/dev/xvda3 1306 1827 4192965 82 Linux swap / Solaris
and We want to make /dev/xvda2 (/ root partition) bigger.
Note1: the following steps are not applicable if you want make /dev/xvda1 (/boot partition) bigger as you will overwrite the root partition.
Note2: enlarging root partition you will overwrite the next partition. In this case it's not a problem as it's the swap partition.
Steps
1. Make sure the VM is down
# xm list
Name ID Mem VCPUs State Time(s)
Domain-0 0 2039 24 r----- 356182.2
oakDom1 2 65536 16 r----- 378770.2
note as from the above command your VM is not listed, if it's present you should stop it using xm
2. Create a new sparse file
To create a new file we need to have enough space on the shared repositories.
check if you have enough space in ASM
[root@oda_base1 ~]# su - grid
[grid@oda_base1 ~]$ . oraenv
ORACLE_SID = [grid] ? +ASM1
The Oracle base has been set to /u01/app/grid
[grid@oda_base1 ~]$ asmcmd
ASMCMD> lsdg
State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name
MOUNTED HIGH N 512 4096 4194304 7372800 4006144 737280 1089621 0 Y DATA/
MOUNTED HIGH N 512 4096 4194304 9796800 7060676 979680 2026998 0 N RECO/
MOUNTED HIGH N 512 4096 4194304 763120 762728 381560 127056 0 N REDO/
ASMCMD>
Take existing snapshot of space available in shared repository.
[grid@oda_base1 ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda2 55G 19G 34G 36% /
/dev/xvda1 460M 24M 413M 6% /boot
/dev/xvdb1 92G 31G 57G 36% /u01
tmpfs 32G 231M 32G 1% /dev/shm
/dev/asm/acfsvol-264 50G 7.5G 43G 15% /cloudfs
/dev/asm/oemvmrepo-264
200G 37G 164G 19% /u01/app/sharedrepo/oemvmrepo
/dev/asm/u02p9007-87 300G 38G 263G 13% /u02p9007
/dev/asm/u02p9008-87 300G 30G 271G 10% /u02p9008
/dev/asm/misp9008-87 50G 240M 50G 1% /misp9008
/dev/asm/misp9007-87 50G 242M 50G 1% /misp9007
Get details for shared repository:
[grid@oda_base1 ~]$ /sbin/advmutil volinfo /dev/asm/oemvmrepo-264
Device: /dev/asm/oemvmrepo-264
Interface Version: 1
Size (MB): 204800
Resize Increment (MB): 32
Redundancy: high
Stripe Columns: 4
Stripe Width (KB): 128
Disk Group: RECO
Volume: OEMVMREPO
Compatible.advm: 11.2.0.4.0
Extend the shared repository by 300G
[grid@oda_base1 ~]$
[grid@oda_base1 ~]$ /sbin/acfsutil size +300G /u01/app/sharedrepo/oemvmrepo
acfsutil size: new file system size: 536870912000 (512000MB)
Confirm the extended space is added to the file system:
[grid@oda_base1 ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda2 55G 19G 34G 36% /
/dev/xvda1 460M 24M 413M 6% /boot
/dev/xvdb1 92G 31G 57G 36% /u01
tmpfs 32G 231M 32G 1% /dev/shm
/dev/asm/acfsvol-264 50G 7.5G 43G 15% /cloudfs
/dev/asm/oemvmrepo-264
500G 38G 463G 8% /u01/app/sharedrepo/oemvmrepo
/dev/asm/u02p9007-87 300G 38G 263G 13% /u02p9007
/dev/asm/u02p9008-87 300G 30G 271G 10% /u02p9008
/dev/asm/misp9008-87 50G 240M 50G 1% /misp9008
/dev/asm/misp9007-87 50G 242M 50G 1% /misp9007
[grid@oda_base1 ~]$
[grid@oda_base1 ~]$
Create a new sparse file (in this example 50G)
cd /OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/
dd if=/dev/zero of=NEW_oel_5.8.img bs=1 count=1024 seek=50GB
# ls -lhs
total 5.1G
1.1M -rw-r--r-- 1 root root 50G Jan 30 02:21 NEW_oel_5.8.img
5.1G -rw-r--r-- 1 root root 5.0G Jan 30 01:44 oel_5.8.img
4.0K -rw-r--r-- 1 root root 496 Jan 30 01:23 vm.cfg
3. Copy the old image on the new
# dd if=oel_5.8.img of=NEW_oel_5.8.img conv=notrunc
29360128+0 records in
29360128+0 records out
15032385536 bytes (15 GB) copied, 464.842 seconds, 32.3 MB/s
# ls -slh /OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/*.img
15G -rw-r--r-- 1 root root 14G Jan 30 01:44 /OVS/Repositories/odarepo2/VirtualMachines/oel_5/oel_5.8.img
11G -rw-r--r-- 1 root root 47G Jan 30 01:44 /OVS/Repositories/odarepo2/VirtualMachines/oel_5/NEW_oel_5.8.img
4. Rename the new image
You may take a backup of your old image
cd /OVS/Repositories/odarepo2/VirtualMachines/oel_5.8
mv oel_5.8.img oel_5.8.img_OLD
mv NEW_oel_5.8.img oel_5.8.img
5. Resize the fs
You need to use "xm block-attach":
modprobe xenblk
xm block-attach 0 'file:/path/to/image/file' xvda w
ie:
# modprobe xenblk
# xm block-attach 0 'file:/OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/oel_5.8.img' xvda w
This will create new device files /dev/xvda (the hole disk) and the partitions you have /dev/xvdaX where X is the partition number
ie:
# ls -l /dev/xvda*
brw-r----- 1 root disk 202, 0 Jan 30 03:26 /dev/xvda
brw-r----- 1 root disk 202, 1 Jan 30 03:26 /dev/xvda1 # in this example this is the boot partition
brw-r----- 1 root disk 202, 2 Jan 30 03:26 /dev/xvda2 # in this example this is the root partition
brw-r----- 1 root disk 202, 5 Jan 30 03:26 /dev/xvda5 # in this example this is the extended swap partition
In this case the root partition is using Ext3 and it can not be resize but ext2 can. So we need to convert the partition ext3 to ext2. The conversion is basically done disabling journal on ext3. Remove the journal on ext3 doing:
tune2fs -O ^has_journal /dev/xvdb2
You can now use any partition editor you want to expand the first partition on /dev/xvda.
For example using fdisk:
# fdisk /dev/xvda
The number of cylinders for this disk is set to 6527.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): p
Disk /dev/xvda: 53.6 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 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 1305 10377990 83 Linux
/dev/xvda3 1306 1827 4192965 82 Linux swap / Solaris
Command (m for help): d
Partition number (1-4): 3
Command (m for help): d
Partition number (1-4): 2
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (14-6527, default 14):
Using default value 14
Last cylinder or +size or +sizeM or +sizeK (14-6078, default 6078): +46G
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3
First cylinder (5608-6078, default 5608):
Using default value 5608
Last cylinder or +size or +sizeM or +sizeK (5608-6078, default 6078):
Using default value 6078
Command (m for help): p
Disk /dev/xvda: 50.0 GB, 50000001024 bytes
255 heads, 63 sectors/track, 6078 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 5607 44933805 83 Linux
/dev/xvda3 5608 6078 3783307+ 83 Linux
Command (m for help): t
Partition number (1-4): 3
Hex code (type L to list codes): 82
Changed system type of partition 3 to 82 (Linux swap / Solaris)
Command (m for help): p
Disk /dev/xvda: 50.0 GB, 50000001024 bytes
255 heads, 63 sectors/track, 6078 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 5607 44933805 83 Linux
/dev/xvda3 5608 6078 3783307+ 82 Linux swap / Solaris
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
6. Resize the filesystem
Now your disk image has new partition size, we need to resize the filesystem as well
a. execute e2fsck required for resizefs
# e2fsck -f /dev/xvda2
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/: 133248/2490880 files (1.8% non-contiguous), 839840/2594497 blocks
b. run resisefs
# resize2fs /dev/xvda2
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/xvda2 to 11233451(4k) blocks.
The filesystem on /dev/xvda2 is now 11233451 blocks long.
c. Turn on the ext3 journal
tune2fs -j /dev/xvdb2
d. When you are done, use "xm block-detach" to release the virtual disk:
# xm block-detach 0 /dev/xvda
You can now startup the VM with the resized disk. Once the VM is up & running you could verify the new disk size using the "df -h" command
Optional step
Check the new size within dom-0
1. Mount the root partition of new disk image
Due to disk partitions we need to skeep the blocks for the /boot partition:
# file ./E1_X86_SYS_913.img
./E1_X86_SYS_913.img: x86 boot sector;
partition 1: ID=0x83, active, starthead 1, startsector 63, 208782 sectors;
partition 2: ID=0x83, starthead 0, startsector 208845, 89867610 sectors;
partition 3: ID=0x82, starthead 254, startsector 90076455, 7566615 sectors, code offset 0x48
To mount a single partition, where X is the startsector of that partition, run:
mount -o loop,offset=$((X*512)) /OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/oel_5.8.img /mnt
example:
mount -o loop,offset=$((208845*512)) /OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/oel_5.8.img /mnt
2. Check the new size
df -h
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/md1 19G 1.2G 17G 7% /
tmpfs 942M 0 942M 0% /dev/shm
/dev/md3 519G 519G 0 100% /OVS
/dev/md0 99M 35M 60M 37% /boot
none 942M 144K 942M 1% /var/lib/xenstored
/OVS/Repositories/odarepo2/VirtualMachines/oel_5.8/oel_5.8.img
42G 3.0G 39G 7% /mnt
3. Umount the filesystem
umount /mnt
Start the vm from oda_base using
oakcli start vm
Verify you have the extended space using df -h
[root@VM1]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda2 285G 23G 248G 9% /
tmpfs 32G 0 32G 0% /dev/shm
/dev/xvda1 487M 75M 387M 17% /boot
