Disk Management in Azure

EXT4 on Ubuntu or Debian running in Azure

Add a new disk for /var

• Check the new Disk

root@vm-ubuntu20:~# lsblk
NAME    MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
loop0     7:0    0 70.3M  1 loop /snap/lxd/21029
loop1     7:1    0 55.4M  1 loop /snap/core18/2128
loop2     7:2    0 32.3M  1 loop /snap/snapd/12883
sda       8:0    0   30G  0 disk
├─sda1    8:1    0 29.9G  0 part /
├─sda14   8:14   0    4M  0 part
└─sda15   8:15   0  106M  0 part /boot/efi
sdb       8:16   0    8G  0 disk
└─sdb1    8:17   0    8G  0 part /mnt
sdc       8:32   0   32G  0 disk

• Label the disk as GPT

root@vm-ubuntu20:~# parted /dev/sdc mklabel gpt
Information: You may need to update /etc/fstab.

• Label the disk as MBR

root@vm-ubuntu20:~# parted /dev/sdc mklabel msdos
Information: You may need to update /etc/fstab.

• Create Patition for GPT label

root@vm-ubuntu20:~# parted /dev/sdc mkpart 1 ext4 0% 100%
Information: You may need to update /etc/fstab.

• Create Patition for MSDOS label

root@vm-ubuntu20:~# parted /dev/sdc mkpart primary  ext4 0% 100%
Information: You may need to update /etc/fstab.

• Create Filesystem

root@vm-ubuntu20:~# mkfs.ext4 /dev/sdc1
mke2fs 1.45.5 (07-Jan-2020)
Discarding device blocks: done
Creating filesystem with 8388352 4k blocks and 2097152 inodes
Filesystem UUID: 8f1da040-7ece-42ea-98a0-1bfe2c200fc7
Superblock backups stored on blocks:
       32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
       4096000, 7962624

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

• Make temp dir

root@vm-ubuntu20:~# mkdir /var-temp

• Mount new disk

root@vm-ubuntu20:~# mount /dev/sdc1 /var-temp

• Copy/Sync data

root@vm-ubuntu20:~# rsync -avAXEWSlHh /var/* /var-temp/ --no-compress

• Get BlockID

root@vm-ubuntu20:~# blkid /dev/sdc1
/dev/sdc1: UUID="4a3968f7-16c1-41f1-8579-0457829de256" TYPE="ext4" PARTUUID="f7a8e367-01"

• Add the disk into /etc/fstab, you shoul use the UUID as device numbers may change after rebooot

echo "UUID=4a3968f7-16c1-41f1-8579-0457829de256       /var        ext4   defaults        0 1" >>/etc/fstab

• Test mount

root@vm-ubuntu20:~# mount -fav
/                        : ignored
/boot/efi                : already mounted
/mnt                     : already mounted
/var                     : successfully mounted

• Reboot

root@vm-ubuntu20:~# init 6

• Test to see the new device for /var

root@vm-ubuntu20:~# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root        29G  1.4G   28G   5% /
devtmpfs        2.0G     0  2.0G   0% /dev
tmpfs           2.0G     0  2.0G   0% /dev/shm
tmpfs           394M  940K  393M   1% /run
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/sdb15      105M  5.2M  100M   5% /boot/efi
/dev/sda1        32G  314M   30G   2% /var
/dev/loop1       33M   33M     0 100% /snap/snapd/12883
/dev/loop0       56M   56M     0 100% /snap/core18/2128
/dev/loop2       71M   71M     0 100% /snap/lxd/21029
/dev/sdc1       7.9G   36M  7.4G   1% /mnt
tmpfs           394M     0  394M   0% /run/user/1000

Extend the disk space for /var

This Lab Test is a follow up from the above, the second hard drive has increased by 32GB to 64GB

• Check with parted, depending on the label you might to run the Fix

root@vm-ubuntu20:~# parted -l /dev/sda
Warning: Not all of the space available to /dev/sda appears to be used, you can
fix the GPT to use all of the space (an extra 67108864 blocks) or continue with
the current setting?
Fix/Ignore? Fix
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 68.7GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name  Flags
 1      1049kB  34.4GB  34.4GB  ext4         1

• Grow the partition

root@vm-ubuntu20:~# growpart /dev/sda 1
CHANGED: partition=1 start=2048 old: size=67104768 end=67106816 new: size=134215647 end=134217695

• Check parted again to see if the size matches

root@vm-ubuntu20:~# parted -l /dev/sda
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 68.7GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name  Flags
 1      1049kB  68.7GB  68.7GB  ext4         1

• Resize the Filesystem

root@vm-ubuntu20:~# resize2fs /dev/sda1
resize2fs 1.45.5 (07-Jan-2020)
Filesystem at /dev/sda1 is mounted on /var-temp; on-line resizing required
old_desc_blocks = 4, new_desc_blocks = 8
The filesystem on /dev/sda1 is now 16776955 (4k) blocks long.

• Check Block Device again and compare with /etc/fstab

LVM on Red Hat or Oracle Linux running in Azure

Extend the disk space for /var

The following samples are taken on a default RedHat82 on Azure

• Check the default disk configuration, in this sample /var has 8GB and is mounted on /dev/mapper/rootvg-varlv

[root@vm-rhe82 ~]# df -h
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   1.9G     0  1.9G   0% /dev
tmpfs                      1.9G     0  1.9G   0% /dev/shm
tmpfs                      1.9G  8.5M  1.9G   1% /run
tmpfs                      1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/rootvg-rootlv  2.0G   71M  2.0G   4% /
/dev/mapper/rootvg-usrlv    10G  1.5G  8.6G  15% /usr
/dev/sda1                  496M  148M  348M  30% /boot
/dev/mapper/rootvg-tmplv   2.0G   47M  2.0G   3% /tmp
/dev/mapper/rootvg-homelv 1014M   40M  975M   4% /home
/dev/sda15                 495M  6.9M  488M   2% /boot/efi
/dev/mapper/rootvg-varlv   8.0G  297M  7.8G   4% /var
/dev/sdb1                  7.9G   36M  7.4G   1% /mnt
tmpfs                      378M     0  378M   0% /run/user/1000

• Check the Logical volume next to see on which volume group we are (rootvg)

[root@vm-rhe82 ~]# lvdisplay /dev/mapper/rootvg-varlv
  --- Logical volume ---
  LV Path                /dev/rootvg/varlv
  LV Name                varlv
  VG Name                rootvg
  LV UUID                L29d2z-WFNF-4vE7-t08B-KPC0-KEUP-utyBYy
  LV Write Access        read/write
  LV Creation host, time localhost, 2021-03-04 12:14:55 +0000
  LV Status              available
  # open                 1
  LV Size                8.00 GiB
  Current LE             2048
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:3

• Check to see if the volume group has space left, in this sample vg01 has 40.02GB left disk space which we can use.

[root@vm-rhe82 ~]# vgdisplay rootvg
 --- Volume group ---
 VG Name               rootvg
 System ID
 Format                lvm2
 Metadata Areas        1
 Metadata Sequence No  6
 VG Access             read/write
 VG Status             resizable
 MAX LV                0
 Cur LV                5
 Open LV               5
 Max PV                0
 Cur PV                1
 Act PV                1
 VG Size               <63.02 GiB
 PE Size               4.00 MiB
 Total PE              16133
 Alloc PE / Size       5888 / 23.00 GiB
 Free  PE / Size       10245 / <40.02 GiB
 VG UUID               3EaPl9-Q0Py-z12t-x1YC-R0MT-D1VN-UNch8o

• Increase /var by 10GB from 8GB to 18GB

[root@vm-rhe82 ~]# lvextend -L +10GB /dev/mapper/rootvg-varlv
 Size of logical volume rootvg/varlv changed from 8.00 GiB (2048 extents) to 18.00 GiB (4608 extents).
 Logical volume rootvg/varlv successfully resized.

• Extend the FXS Filesystem
  • Use -n to test

[root@vm-rhe82 ~]#  xfs_growfs /dev/mapper/rootvg-varlv
meta-data=/dev/mapper/rootvg-varlv isize=512    agcount=4, agsize=524288 blks
        =                       sectsz=4096  attr=2, projid32bit=1
        =                       crc=1        finobt=1, sparse=1, rmapbt=0
        =                       reflink=1
data     =                       bsize=4096   blocks=2097152, imaxpct=25
        =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
        =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 2097152 to 4718592

• Check the result again and compare with the result from above, /var has now 18GB

[root@vm-rhe82 ~]# df -h
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   1.9G     0  1.9G   0% /dev
tmpfs                      1.9G     0  1.9G   0% /dev/shm
tmpfs                      1.9G  8.5M  1.9G   1% /run
tmpfs                      1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/rootvg-rootlv  2.0G   71M  2.0G   4% /
/dev/mapper/rootvg-usrlv    10G  1.5G  8.6G  15% /usr
/dev/sda1                  496M  148M  348M  30% /boot
/dev/mapper/rootvg-tmplv   2.0G   47M  2.0G   3% /tmp
/dev/mapper/rootvg-homelv 1014M   40M  975M   4% /home
/dev/sda15                 495M  6.9M  488M   2% /boot/efi
/dev/mapper/rootvg-varlv    18G  462M   18G   3% /var
 /dev/sdb1                  7.9G   36M  7.4G   1% /mnt
tmpfs                      378M     0  378M   0% /run/user/1000

• Check the volume group again, the entire space has decreased by 10GB

[root@vm-rhe82 ~]# vgdisplay rootvg
 --- Volume group ---
 VG Name               rootvg
 System ID
 Format                lvm2
 Metadata Areas        1
 Metadata Sequence No  7
 VG Access             read/write
 VG Status             resizable
 MAX LV                0
 Cur LV                5
 Open LV               5
 Max PV                0
 Cur PV                1
 Act PV                1
 VG Size               <63.02 GiB
 PE Size               4.00 MiB
 Total PE              16133
 Alloc PE / Size       8448 / 33.00 GiB
 Free  PE / Size       7685 / <30.02 GiB
 VG UUID               3EaPl9-Q0Py-z12t-x1YC-R0MT-D1VN-UNch8o

Extend the OS Disk

• Teslab on Azure using RedHat8.2, in Azure we increase the Disk size from 65GB to 128GB. This is howto add the new disk space to LVM

List the disk with parted, on the first run we will need to fix the new size by typing Fix

[root@vm-rhe82 ~]# parted -l /dev/sda
Warning: Not all of the space available to /dev/sda appears to be used, you can
fix the GPT to use all of the space (an extra 134217728 blocks) or continue with
the current setting?
Fix/Ignore? Fix
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 137GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                  Flags
14      1049kB  5243kB  4194kB                                     bios_grub
15      5243kB  524MB   519MB   fat16        EFI System Partition  boot, esp
 1      525MB   1050MB  524MB   xfs
 2      1050MB  68.7GB  67.7GB                                     lvm

• Next we need to know where to expand the new partition, this sample shows /dev/sda2

[root@vm-rhe82 ~]# pvdisplay
 --- Physical volume ---
 PV Name               /dev/sda2
 VG Name               rootvg
 PV Size               63.02 GiB / not usable 2.00 MiB
 Allocatable           yes
 PE Size               4.00 MiB
 Total PE              16133
 Free PE               7685
 Allocated PE          8448
 PV UUID               uevLg0-eCem-PQIV-0lUJ-ViuH-BQPi-C4PSIo

• Optional confirm with lsblk

[root@vm-rhe82 ~]# lsblk
NAME              MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                 8:0    0  128G  0 disk
├─sda1              8:1    0  500M  0 part /boot
├─sda2              8:2    0   63G  0 part
│ ├─rootvg-tmplv  253:0    0    2G  0 lvm  /tmp
│ ├─rootvg-usrlv  253:1    0   10G  0 lvm  /usr
│ ├─rootvg-homelv 253:2    0    1G  0 lvm  /home
│ ├─rootvg-varlv  253:3    0   18G  0 lvm  /var
│ └─rootvg-rootlv 253:4    0    2G  0 lvm  /
├─sda14             8:14   0    4M  0 part
└─sda15             8:15   0  495M  0 part /boot/efi
sdb                 8:16   0    8G  0 disk
└─sdb1              8:17   0    8G  0 part /mnt

• The above information shows partition number 2 which we wnat to grow up to 128GB

[root@vm-rhe82 ~]# growpart /dev/sda 2
CHANGED: partition=2 start=2050048 old: size=132165632 end=134215680 new: size=266385375 end=268435423

• Parted shows now the new disk space for /dev/sda2

[root@vm-rhe82 ~]# parted -l /dev/sda
Model: Msft Virtual Disk (scsi)
Disk /dev/sda: 137GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                  Flags
14      1049kB  5243kB  4194kB                                     bios_grub
15      5243kB  524MB   519MB   fat16        EFI System Partition  boot, esp
 1      525MB   1050MB  524MB   xfs
 2      1050MB  137GB   136GB                                      lvm

• Now resize the disk within LVM

[root@vm-rhe82 ~]# pvresize /dev/sda2
  Physical volume "/dev/sda2" changed
  1 physical volume(s) resized or updated / 0 physical volume(s) not resized

• Check the volume group again, compare it from the result above to see how rootvg increased

[root@vm-rhe82 ~]# vgdisplay
 --- Volume group ---
 VG Name               rootvg
 System ID
 Format                lvm2
 Metadata Areas        1
 Metadata Sequence No  8
 VG Access             read/write
 VG Status             resizable
 MAX LV                0
 Cur LV                5
 Open LV               5
 Max PV                0
 Cur PV                1
 Act PV                1
 VG Size               <127.02 GiB
 PE Size               4.00 MiB
 Total PE              32517
 Alloc PE / Size       8448 / 33.00 GiB
 Free  PE / Size       24069 / <94.02 GiB
 VG UUID               3EaPl9-Q0Py-z12t-x1YC-R0MT-D1VN-UNch8o

Add a new Disk and replace the mount point /var to the new disk

Teslab on Azure using RedHat8.2, in Azure we added a new disk which we want to replace with /var

• Check to see which partition came on new, see the kernel messages, this sample shows sdc as the latest disk which came on our system

[root@vm-rhe82 ~]# dmesg | grep Attached
[    4.960356] scsi 0:0:0:0: Attached scsi generic sg0 type 0
[    4.992214] scsi 0:0:0:1: Attached scsi generic sg1 type 0
[    5.228196] sd 0:0:0:1: [sdb] Attached SCSI disk
[    5.354066] sd 0:0:0:0: [sda] Attached SCSI disk
[ 2675.092988] sd 1:0:0:0: Attached scsi generic sg2 type 0
[ 2675.145990] sd 1:0:0:0: [sdc] Attached SCSI disk

• Next is to create the new disk in LVM

[root@vm-rhe82 ~]# pvcreate /dev/sdc
  Physical volume "/dev/sdc" successfully created.

• Next is to create the new volume group in LVM, we call the volume group as vg01

[root@vm-rhe82 ~]# vgcreate vg01 /dev/sdc
  Volume group "vg01" successfully created

• Next is to create the logcal volume in LVM, we call the logical volume group as lv01 and use all space

[root@vm-rhe82 ~]# lvcreate -n lv01 -l 100%FREE vg01
  Logical volume "lv01" created.

• As the disk is new, we need to create a filesystem before to proceed

[root@vm-rhe82 ~]# mkfs.xfs /dev/vg01/lv01
meta-data=/dev/vg01/lv01         isize=512    agcount=4, agsize=4194048 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=16776192, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=8191, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

• Now create a temp folder for /var, say we create /var-temp

[root@vm-rhe82 ~]# mkdir /var-temp

• Next mount our new disk to here:

[root@vm-rhe82 ~]# mount /dev/vg01/lv01 /var-temp

• Check the result, /var-temp should come up and we show also to which we want to replace

[root@vm-rhe82 ~]# df -h
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   1.9G     0  1.9G   0% /dev
tmpfs                      1.9G     0  1.9G   0% /dev/shm
tmpfs                      1.9G  8.5M  1.9G   1% /run
tmpfs                      1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/rootvg-rootlv  2.0G   71M  2.0G   4% /
/dev/mapper/rootvg-usrlv    10G  1.5G  8.6G  15% /usr
/dev/mapper/rootvg-tmplv   2.0G   47M  2.0G   3% /tmp
/dev/mapper/rootvg-homelv 1014M   40M  975M   4% /home
/dev/sda1                  496M  148M  348M  30% /boot
/dev/sda15                 495M  6.9M  488M   2% /boot/efi
/dev/mapper/rootvg-varlv    18G  440M   18G   3% /var
/dev/sdb1                  7.9G   36M  7.4G   1% /mnt
tmpfs                      378M     0  378M   0% /run/user/1000
/dev/mapper/vg01-lv01       64G  489M   64G   1% /var-temp

• Copy the actual data to var-temp, keep the exact file attributes

[root@vm-rhe82 ~]# rsync -avAXEWSlHh /var/* /var-temp/ --no-compress

• Add the new disk into etc/fstab
  • Make sure that there are no more mount points to /var

echo  "/dev/mapper/vg01-lv01 /var xfs defaults 0 0" >> /etc/fstab

• Check to see if we are ok by test:

[root@vm-rhe82 ~]# mount -fav
/                        : ignored
/boot                    : already mounted
/boot/efi                : already mounted
/home                    : already mounted
/tmp                     : already mounted
/usr                     : already mounted
/mnt                     : already mounted
/var                     : successfully mounted

• Reboot and cross fingers

[root@vm-rhe82 ~]# init 6

• After reboot check the result:

[root@vm-rhe82 ~]# df -h
Filesystem                 Size  Used Avail Use% Mounted on
devtmpfs                   1.9G     0  1.9G   0% /dev
tmpfs                      1.9G     0  1.9G   0% /dev/shm
tmpfs                      1.9G   17M  1.9G   1% /run
tmpfs                      1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/rootvg-rootlv  2.0G   71M  2.0G   4% /
/dev/mapper/rootvg-usrlv    10G  1.5G  8.6G  15% /usr
/dev/mapper/rootvg-tmplv   2.0G   47M  2.0G   3% /tmp
/dev/mapper/rootvg-homelv 1014M   40M  975M   4% /home
/dev/sda1                  496M  148M  348M  30% /boot
/dev/sda15                 495M  6.9M  488M   2% /boot/efi
/dev/mapper/vg01-lv01       64G  764M   64G   2% /var
/dev/sdb1                  7.9G   36M  7.4G   1% /mnt
tmpfs                      378M     0  378M   0% /run/user/1000

• Check the VG size again

[root@vm-rhe82 ~]# vgdisplay rootvg | grep -i  free
  Free  PE / Size       24069 / <94.02 GiB

• Cleanup: Delete the old logical volume group

[root@vm-rhe82 ~]# lvremove /dev/rootvg/varlv
 Do you really want to remove active logical volume rootvg/varlv? [y/n]: y
  Logical volume "varlv" successfully removed

• Check the VG size again

[root@vm-rhe82 ~]# vgdisplay rootvg | grep -i  free
  Free  PE / Size       28677 / <112.02 GiB

List Commands

• List Disks

lshw -class disk
lvmdiskscan 

• List Size and add Total

df -h --output=size --total

• Automount from fstab

mount -a

• Simulate

mount -fav

Links

• https://docs.microsoft.com/en-us/azure/virtual-machines/linux/resize-os-disk-gpt-partition
• https://www.shellbefehle.de