Expand Disk Storage for Analytics Nodes

Configure a New Partition for an MBR Format Disk

To create a new partition from unassigned sectors on an existing MBR disk using the available disk space:

1. To edit the partition table for your disk, use the Linux cfdisk utility. Use this utility on the disk device file listed in the output of the fdisk command, as described in Display Total Available VM Disk Storage, above. The utility copies the partition table from the disk into memory so that you can edit it. The utility displays the following screen, which includes a partition-editing menu and information about the disk, such as its current partitions and free space. In the following example, the screens shows that the disk has is approximately 1 TB of free space (1048577.05 MB) after partition 5 (sda5). You can use this space to create a new partition.

admin@versa-vm$ sudo cfdisk /dev/sda

2. Use the up and down arrow keys to highlight the Free space to assign to the new partition. A new menu displays at the bottom of the screen.
   
   
3. Use the right and left arrow keys to highlight New in the menu at the bottom of the screen.
4. Press the Enter key. You are prompted to select a partition type.
   
   
    
5. Use the arrow keys to highlight Primary, and then press the Enter key. The Size prompt displays.
   
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6. Enter a size for the new partition, in megabytes, and then press the Enter key. The cfdisk utility selects a partition number and then adds the partition to the in-memory partition table. In the following example, cfdisk has created partition 3 (sda3), which is 1048577.05 MB (1 TB) in size.
   
   
    
7. By default, the cfdisk utility creates the new partition with filesystem type Linux. To change this to the Linux LVM type, use the arrow keys to highlight Type in the menu at the bottom of the screen, and then press Enter.
8. When you are prompted to enter the filesystem type, enter 8e and then press Enter.
   
   
   
   The filesystem type changes to Linux LVM:
   
   
9. Use the arrow keys to highlight Write, and then press Enter.
10. When prompted to save your changes, type yes and then press Enter. The edited partition table is saved to the disk.
11. Use the arrows keys to highlight Quit, and then press Enter to exit the cfdisk utility.
12. Reboot the node. Note that a reboot is not required for nodes running Ubuntu 18.04 (Bionic).
13. When the reboot completes, log in to a shell on the node, and then issue the lsblk command. The output includes the new partition. Make a note of the device filename for the partition, which is the /dev directory prepended to the partition name. In the example here, the new partition is sda3 and its device filename is /dev/sda3.

admin@Analytics$ lsblk
NAME                     MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                        8:0    0     1T  0 disk
├─sda1                     8:1    0   243M  0 part /boot
├─sda2                     8:2    0     1K  0 part
├─sda3                     8:3    0 976.6G  0 part
└─sda5                     8:5    0  79.8G  0 part
  ├─system-root (dm-0)   252:0    0  71.7G  0 lvm  /
  └─system-swap_1 (dm-1) 252:1    0     8G  0 lvm
sr0                       11:0    1  1024M  0 rom

Initialize the New MBR Partition

To initialize the new partition, issue the sudo pvcreate device-filename command. Use the device filename for the partition you created in the previous section. For example:

admin@Analytics$ sudo pvcreate /dev/sda3
  Physical volume "/dev/sda3" successfully created

Add the MBR Partition to a Volume Group

Before you can extend the root filesystem, you must add the new partition to a volume group.

To add the new partition to the root filesystem's volume group:

1. To display the existing volume group configuration, issue the sudo vgdisplay command. Typically, the node contains only the volume group named "system".

 admin@Analytics$ sudo vgdisplay
  --- Volume group ---
  VG Name               system
  System ID
  
  (Output omitted for brevity.)

2. To add the partition to an existing volume group, issue the sudo vgextend volume-group partition-name command. For volume-group, use the volume group name from Step 1. For partition-name, use the device filename you used in the sudo pvcreate command. For example:

admin@Analytics$ sudo vgextend system /dev/sda3
  Volume group "system" successfully extended 

Additional storage is now included in the volume group, although the storage is not yet mapped to any logical volumes.

Extend the Logical Volume Using an MBR Partition

To extend the logical volume:

1. To increase the size of the logical volume for the root filesystem, issue the lvextend command. The command uses the device file /dev/system/root, which is a link to the device file for the root filesystem, which, in this example, is /dev/dm-0. The –l+100%FREE argument adds all available free disk space to the logical volume. In the example here, the lvextend command adds the disk space from partition 3 to logical volume dm-0, so that dm-0 now contains most of partition 5 and all of partition 3.

   admin@Analytics$ sudo lvextend -l+100%FREE /dev/system/root

2. To display which partitions are now included in the logical volume, issue the lsblk command. In the following example output, the command verifies that dm-0 now includes the new partition.

admin@Analytics$ lsblk
NAME                     MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                        8:0    0     1T  0 disk
├─sda1                     8:1    0   243M  0 part /boot
├─sda2                     8:2    0     1K  0 part
├─sda3                     8:3    0 976.6G  0 part
│ └─system-root (dm-0)   252:0    0     1T  0 lvm  /
└─sda5                     8:5    0  79.8G  0 part
  ├─system-root (dm-0)   252:0    0     1T  0 lvm  /
  └─system-swap_1 (dm-1) 252:1    0     8G  0 lvm
sr0                       11:0    1  1024M  0 rom

Extend the Root Filesystem

To have the root filesystem use the additional storage, you update data structures to resize the filesystem.

To resize the root filesystem:

1. Issue the resize2fs command. This command uses the device file /dev/mapper/system-root, which is a link to the device file for the root filesystem, in this example, /dev/dm-0.

admin@Analytics$ sudo resize2fs /dev/mapper/system-root

2. To verify that the root filesystem has been allocated additional disk space, issue the df –kh command.

admin@Analytics$ df -kh
Filesystem      Size  Used Avail Use% Mounted on
udev            7.9G   12K  7.9G   1% /dev
tmpfs           1.6G  348K  1.6G   1% /run
/dev/dm-0       1.1T  4.3G  985G   1% /
none            4.0K     0  4.0K   0% /sys/fs/cgroup
none            5.0M     0  5.0M   0% /run/lock
none            7.9G   32K  7.9G   1% /run/shm
none            100M     0  100M   0% /run/user
/dev/sda1       236M   79M  145M  36% /boot

The Analytics > Administration > System Status > Status screen in the Director GUI also displays the increased storage. In the following example, steps were performed on both nodes of the cluster so that they both display an increase in the Disk Free column.


 

Configure a New Partition for a GPT Format Disk

To create a new partition from unassigned sectors on an existing GPT disk using the available disk space:

1. To edit the partition table for your disk, use the Linux gdisk utility. Use this utility on the disk device file listed in the output of the fdisk command, as described in Display Total Available VM Disk Storage, above. The utility copies the partition table from the disk into memory so that you can edit it.

admin@Analytics$ sudo gdisk /dev/sde
GPT fdisk (gdisk) version 0.8.8
Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): n

2. Enter n to create a new partition.

Partition number (1-128, default 1):
First sector (34-6476005342, default = 40) or {+-}size{KMGTP}:
Last sector (40-6476005342, default = 6476005342) or {+-}size{KMGTP}:
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300): 8e00
Changed type of partition to 'Linux LVM'
Command (? for help): w

3. Enter values for the partition number, first sector, and last sector. In the above example, the user presses Enter three times to accept the default values.
4. Enter 8e00 for the Hex code or GUID value. This marks the partition as type Linux LVM.
5. Enter w to save your changes to the in-memory copy of the partition table.

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
Do you want to proceed? (Y/N): Y
OK; writing new GUID partition table (GPT) to /dev/sde.
The operation has completed successfully.

6. Enter Y to save your changes to the partition table on disk.
7. Issue the lsblk command to display the new partition. In the example here, the new partition is sde1 and its device filename is /dev/sde1.

admin@Analytics$ lsblk
sda                        8:0    0    80G  0 disk
├─sda1                     8:1    0   243M  0 part /boot
├─sda2                     8:2    0     1K  0 part
└─sda5                     8:5    0  79.8G  0 part
  ├─system-root (dm-0)   252:0    0  71.7G  0 lvm  /
  └─system-swap_1 (dm-1) 252:1    0     8G  0 lvm
sde                        8:64   0     3T  0 disk
`-sde1                     8:65   0     3T  0 part
sr0                       11:0    1  1024M  0 rom

Initialize the New GPT Partition

To initialize the new partition, issue the sudo pvcreate device-filename command. Use the device filename for the partition you created in the previous section. For example:

admin@Analytics$ sudo pvcreate /dev/sde1
  Physical volume "/dev/sde1" successfully created

Add the GPT Partition to a Volume Group

1. To display the existing volume group configuration, issue the sudo vgdisplay command. Typically, the node contains only the volume group named "system".

 admin@Analytics$ sudo vgdisplay
  --- Volume group ---
  VG Name               system
  System ID
  
  (Output omitted for brevity.)

2. To add the partition to an existing volume group, issue the sudo vgextend volume-group partition-name –An command. For volume-group, use the volume group name from the previous step. For partition-name, use the device filename you used in the sudo pvcreate command. For example:

admin@Analytics$ sudo vgextend system /dev/sde1 -An
  Volume group "system" successfully extended

Extend the Logical Volume Using a GPT Partition

To extend the logical volume:

1. To increase the size of the logical volume for the root filesystem, issue the lvextend command with the -An option. The command uses the device file /dev/system/root, which is a link to the device file for the root filesystem. The –l+100%FREE argument adds all available free disk space to the logical volume. In the example here, the lvextend command adds the disk space from partition sde1.

admin@Analytics$ sudo lvextend -l+100%FREE /dev/system/root -An
Extending logical volume root to 3.92 TiB
WARNING: This metadata update is NOT backed up
Logical volume root successfully resized

2. To display which partitions are now included in the logical volume, issue the lsblk command.

admin@Analytics$ lsblk

Extend the Root Filesystem

To have the root filesystem use the additional storage, you update data structures to resize the filesystem.

To resize the root filesystem:

1. Issue the resize2fs command. This command uses the device file /dev/mapper/system-root, which is a link to the device file for the root filesystem.

admin@Analytics$ sudo resize2fs /dev/mapper/system-root
resize2fs 1.42.9 (4-Feb-2014)
Filesystem at /dev/mapper/system-root is mounted on /; on-line resizing required
old_desc_blocks = 58, new_desc_blocks = 252
The filesystem on /dev/mapper/system-root is now 1052965888 blocks long.

2. To verify that the root filesystem has been allocated additional disk space, issue the df –kh command.

admin@Analytics$ df -kh
Filesystem                 Size  Used Avail Use% Mounted on
/dev/mapper/system-root    3.9T  694G  3.1T  19% /
none                       4.0K     0  4.0K   0% /sys/fs/cgroup
udev                        32G   12K   32G   1% /dev

(Output omitted for brevity.)