Extend harddisk size of Linux
by sij /
The hypervisor Proxmox gives you the ability to extend virtual harddisks of your virtual machines. This “How To” explains how to extend the virtual disk of a virtualized Linux.
Information
The virtual machine is a Linux Debian 9.6 which uses the filesystem ext4. The disk will be extended from 21 GB to 22 GB.
How To
Get the current partition table
root@vlx-project:/home/sij# fdisk -l
Disk /dev/vda: 22 GiB, 23622320128 bytes, 46137344 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xfc0f9abd
Device Boot Start End Sectors Size Id Type
/dev/vda1 * 2048 39847935 39845888 19G 83 Linux
/dev/vda2 39847936 44040191 4192256 2G 5 Extended
/dev/vda5 39849984 44040191 4190208 2G 82 Linux swap / SolariEdit the partition table
root@vlx-project:/home/sij# fdisk /dev/vda
Welcome to fdisk (util-linux 2.29.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): d
Partition number (1,2,5, default 5):
Partition 5 has been deleted.
Command (m for help): d
Partition number (1,2, default 2):
Partition 2 has been deleted.
Command (m for help): d
Selected partition 1
Partition 1 has been deleted.
Command (m for help): n
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p):
Using default response p.
Partition number (1-4, default 1):
First sector (2048-46137343, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-46137343, default 46137343): +20G
Created a new partition 1 of type 'Linux' and of size 20 GiB.
Partition #1 contains a ext4 signature.
Do you want to remove the signature? [Y]es/[N]o: N
Command (m for help): n
Partition type
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): e
Partition number (2-4, default 2):
First sector (41945088-46137343, default 41945088):
Last sector, +sectors or +size{K,M,G,T,P} (41945088-46137343, default 46137343):
Created a new partition 2 of type 'Extended' and of size 2 GiB.
Command (m for help): n
All space for primary partitions is in use.
Adding logical partition 5
First sector (41947136-46137343, default 41947136):
Last sector, +sectors or +size{K,M,G,T,P} (41947136-46137343, default 46137343):
Created a new partition 5 of type 'Linux' and of size 2 GiB.
Command (m for help): t
Partition number (1,2,5, default 5):
Partition type (type L to list all types): 82
Changed type of partition 'Linux' to 'Linux swap / Solaris'.
Command (m for help): a
Partition number (1,2,5, default 5): 1
The bootable flag on partition 1 is enabled now.
Command (m for help): p
Disk /dev/vda: 22 GiB, 23622320128 bytes, 46137344 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xfc0f9abd
Device Boot Start End Sectors Size Id Type
/dev/vda1 * 2048 41945087 41943040 20G 83 Linux
/dev/vda2 41945088 46137343 4192256 2G 5 Extended
/dev/vda5 41947136 46137343 4190208 2G 82 Linux swap / Solaris
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Das Gerät oder die Ressource ist belegt
The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8).It is important, that the partition which contains all data, starts at the same block as before. The partitions vda2 and vda5 can be moved, because these contain no data. Is the swap partition.
root@vlx-project:/home/sij# rebootReconfigure the swap partition
During the reboot the following error appears:
A start job is running for dev-disk-by\x2duuid-d3acc93e\x2d...b5\x2d4cdd\x2d9915\x2d64882eda7f82.device (11s / 1 min 30s)This is caused by the change of the uuid of the swap partition. The old uuid, which doesnt exist anymore, is still in the /etc/fstab. To fix this error, we need to initialize the new swap partition and replace the old uuid by the new one.
root@vlx-project:/home/sij# cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/vda1 during installation
UUID=4b18fd12-cf9d-4f71-8e86-bfe13c2ff7b4 / ext4 errors=remount-ro 0 1
# swap was on /dev/vda5 during installation
UUID=d3acc93e-c6b5-4cdd-9915-64882eda7f82 none swap sw 0 0
/dev/sr0 /media/cdrom0 udf,iso9660 user,noauto 0 0
root@vlx-project:/home/sij# mkswap /dev/vda5
Setting up swapspace version 1, size = 2 GiB (2145382400 bytes)
no label, UUID=8dacbe0b-f8ea-4939-8eb2-9b919dacf657The old swap uuid can now be replaced by the new one.
Resize the filesystem
The partition is now bigger, but the filesystem is still 19 GB and not the expected 20 GB.
root@vlx-project:/home/sij# df -h
Dateisystem Größe Benutzt Verf. Verw% Eingehängt auf
udev 992M 0 992M 0% /dev
tmpfs 201M 3.0M 198M 2% /run
/dev/vda1 19G 4.9G 13G 28% /
tmpfs 1003M 0 1003M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 1003M 0 1003M 0% /sys/fs/cgroup
tmpfs 201M 0 201M 0% /run/user/1000
root@vlx-project:/home/sij# resize2fs /dev/vda1
resize2fs 1.43.4 (31-Jan-2017)
Dateisystem bei /dev/vda1 ist auf / eingehängt; Online-Größenänderung ist
erforderlich
old_desc_blocks = 3, new_desc_blocks = 3
Das Dateisystem auf /dev/vda1 is nun 5242880 (4k) Blöcke lang.
root@vlx-project:/home/sij# df -h
Dateisystem Größe Benutzt Verf. Verw% Eingehängt auf
udev 992M 0 992M 0% /dev
tmpfs 201M 3.0M 198M 2% /run
/dev/vda1 20G 4.9G 14G 27% /
tmpfs 1003M 0 1003M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 1003M 0 1003M 0% /sys/fs/cgroup
tmpfs 201M 0 201M 0% /run/user/1000