Managing instance storage

Listing the block devices on your instance

On Linux®, you can use the lsblk command to list the block devices after you logged in to your instance. In the following example, the instance that is provisioned has two 600 GB instance disks and two 50 GiB data volumes. A list of custom columns is specified to the lsblk command to highlight some differences between instance storage and remote Block Storage.

Instance Disks are measured in gigabytes (GB), but lsblk shows size in gibibyte (GiB).

$ lsblk -o NAME,SIZE,MAJ:MIN,TYPE,PHY-SEC,LOG-SEC,MOUNTPOINT
NAME          SIZE MAJ:MIN TYPE PHY-SEC LOG-SEC MOUNTPOINT
vda           100G 252:0   disk     512     512
├─vda1          1G 252:1   part     512     512 /boot
└─vda2         99G 252:2   part     512     512
  ├─cl-root    97G 253:0   lvm      512     512 /
  └─cl-swap   2.1G 253:1   lvm      512     512
vdb         558.8G 252:16  disk    4096    4096
vdc         558.8G 252:32  disk    4096    4096
vdd            50G 252:48  disk     512     512
vde            50G 252:64  disk     512     512
vdf           366K 252:80  disk     512     512
vdg            44K 252:96  disk     512     512

In this example all of the Block Storage devices are virtio_blk devices:

• vda is the boot volume.
• vdb and vdc are the 600 GB instance storage disks. In Linux®, instance storage disks follow the boot volume with the first one being /dev/vdb. Since the lsblk command is displaying “G” units as base-2 gibibytes, the size is displayed as 558.8 GiBs. The sector size column values might differ depending on the operating system or the generation of profile. For example, x3d instance profile families might provision with 512 byte sector sizes for local disks.
• vdd and vde are remote data volumes that are attached to the instance. Since these data volumes are requested in the same units as lsblk is displaying, their size remains as whole GiBs (50).
• vdf and vdg are small block volumes that are used for the cloud-init configuration of the instance.

Using the Metadata service to list instance storage

The metadata service can be used from within the instance to retrieve information about the instance, including instance storage disks. To retrieve metadata information, the metadata service capability must be enabled when the instance is provisioned or by updating the instance afterward. For more information on enabling and usage procedure, see Accessing metadata from an instance.

If you have an instance with the Metadata service enabled, the following steps demonstrate an example of utilizing instance storage metadata from a Linux virtual server.

1. Retrieve a short-lived instance identity token.

   instance_identity_token=`curl -X PUT "http://api.metadata.cloud.ibm.com/instance_identity/v1/token?version=2024-02-20" -H "Metadata-Flavor: ibm" -H "Accept: application/json" -d '{ "expires_in": 300 }' | jq -r '(.access_token)'`
   

   Use HTTPS instead of HTTP if the secure metadata service endpoint is enabled. You might need to install curl or jq packages before running the curl command. For example: sudo apt install jq

2. Use the token to obtain instance metadata and select the disks portion and store the json in a bash variable.

   disks=$(curl -sS -X GET "http://api.metadata.cloud.ibm.com/metadata/v1/instance?version=2024-02-20" -H "Authorization: Bearer $instance_identity_token" | jq -r '.disks')
   

3. Loop over virtio devices in /dev/disk/by-id and correlate device paths to the instance disk information stored in the previous step.

   for ln in $(ls /dev/disk/by-id/virtio*); do b=$(basename $ln); s=${b#virtio-}; disk=$(echo $disks | jq -r ".[] | select(.id | startswith(\"$s\"))"); if [ -n "$disk" ]; then echo "$ln $(readlink -f $ln) $(echo $disk | jq -r '(.size|tostring) + " " + .name')";fi;done
   

The following is example output of the prior command where the column order is (1) by-id path, (2) symlink device target, (3) size in GB, and (4) the Cloud UI/CLI/API disk name:

/dev/disk/by-id/virtio-0736-35db69bb-d09b-4 /dev/vdc 600 palmtree-vacuumed-judiciary-wharf
/dev/disk/by-id/virtio-0736-874803ac-2593-4 /dev/vdb 600 lunacy-dismantle-dotted-fiddling

In this case, the disk names are the random four-word generated names, but these can be edited to have custom names. For more information, see Updating one of the default names.

Partitioning, formatting, and mounting instance storage disks

The instance storage disks can be partitioned, formatted with a file system, and mounted into the hierarchical file system in the same manner as the remote block volumes.

• For instructions for Linux®, see Set up your Block Storage for VPC data volume for use (Linux) or Configuring a single disk instance storage by using the cloud-config script.
• For Windows®, use the Computer Management UI to bring a block volume online, partition, and format it. For more information, see Set up your Block Storage for VPC data volume for use (Windows).

The following lsblk example shows the output after logging into a bx3d-48x240 instance and partitioning vdc into two primary partitions, formatting them with separate file systems, and mounting them. The grep command with reqular expression is used to filter the output to just the vdb and vdc devices obtained through the Metadata service (refer to the prior section).

$ lsblk | grep -E "NAME|vd[b|c]"
NAME    MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
vdb     252:16   0 726.4G  0 disk
vdc     252:32   0 726.4G  0 disk
├─vdc1  252:33   0   200G  0 part /mnt/localdisk1
└─vdc2  252:34   0 526.4G  0 part /mnt/localdisk2

Due to the ephemeral nature of instance storage, configure the mount entry in the Linux® VM’s /etc/fstab file with the nofail option, or leave the mount entry out entirely. This setting avoids a mount failure during boot.

The following example shows a mount entry with the nofail option.

/dev/vdb1 /mnt/inststg1 ext4 defaults,nofail 0 0

Looking up instance storage details of an instance profile

Look for the instance storage column in the web UI or CLI when you filter instance profiles. It may be called Storage(GB).

The following examples show possible column values and what they mean:

• 1 x 150 GB – A single 150 GB block device is attached to the virtual server instance for instance storage.
• 2 x 600 GB – Two 600 GB (1200 total) instance storage block devices are attached.

In some contexts, you might see an Interface Type (usually virtio_blk) for an instance profile or for an attached instance disk. The following example shows details that were obtained from the CLI for a specific instance profile.

$ ibmcloud is in-pr bx2d-48x192
Getting instance profile bx2d-48x192 under account YYYYYY as user vpc-user@myco.com...

Name                     bx2d-48x192
Architecture             amd64
vCPU Manufacturer        intel
Family                   balanced
vCPUs                    48
Memory(GiB)              192
GPU                      Model   Manufacturer   Count   Memory(GiB)
                         -       -              -       -

Numa Count               -
Bandwidth(Mbps)          80000
Volume bandwidth(Mbps)   -
Instance Storage Disks   Quantity   Size   Supported interface types
                         2          900    virtio_blk

Min NIC Count            1
Max NIC Count            10

Reporting instance storage information

You can report instance storage information for your virtual server instance by using the following CLI example. Substitute your own instance ID or name.

$ ibmcloud is instance-disks 0716_f8c0fd3b-cada-46c3-91f6-c271937ef488
Listing disks of instance 0716_f8c0fd3b-cada-46c3-91f6-c271937ef488 under account YYYYYY as user vpc-user@myco.com...
ID                                          Name                               Size   Interface Type
0716-6ebed02f-c421-4b06-a73b-f334413e84b3   clunky-refocus-tidings-underpaid   600    virtio_blk
0716-54ee0659-d92a-4d4c-ac6b-8f03cb178a07   linguini-epiphany-lush-preschool   600    virtio_blk

Updating one of the default names

You can update the custom names of the instance storage disks by using the following CLI command. Substitute your own instance ID and disk ID for the last two parameters, respectively.

$ ibmcloud is instance-disk-update 0716_f8c0fd3b-cada-46c3-91f6-c271937ef488 0716-6ebed02f-c421-4b06-a73b-f334413e84b3 --name my-instance-disk1
Updating instance disk 0716-6ebed02f-c421-4b06-a73b-f334413e84b3 of instance 0716_f8c0fd3b-cada-46c3-91f6-c271937ef488 under account YYYYYY as user vpc-user@myco.com...

ID               0716-6ebed02f-c421-4b06-a73b-f334413e84b3
Name             my-instance-disk1
Size             600
Interface Type   virtio_blk
Created          2020-10-29T22:57:15-05:00

$ ibmcloud is instance-disks 0716_f8c0fd3b-cada-46c3-91f6-c271937ef488
Listing disks of instance 0716_f8c0fd3b-cada-46c3-91f6-c271937ef488 under account YYYYYY as user vpc-user@myco.com...
ID                                          Name                               Size   Interface Type
0716-6ebed02f-c421-4b06-a73b-f334413e84b3   my-instance-disk1                  600    virtio_blk
0716-54ee0659-d92a-4d4c-ac6b-8f03cb178a07   linguini-epiphany-lush-preschool   600    virtio_blk