Snapshots and Clones

With snapshots and clones, you can leverage fast and thin point-in-time snapshots/clones of Lightbits volumes. A snapshot can be taken from a volume, and a volume can be created from a snapshot (aka a clone).

Creating the Initial Volume on Lightbits

To create a sample volume:

root@rack03-server72:~ lbcli create volume --size="25 Gib" --name=vol1 --acl="acl3" --replica-count=1 --project-name=default

Name UUID State Protection State NSID Size Replicas Compression ACL Rebuild Progress

vol1 01b20f49-13d6-468f-b82d-752594922a6e Creating Unknown 0 25 GiB 1 false values:"acl3"

Get the cluster details for attaching the volume to the client.

root@rack03-server72:~ lbcli get cluster

UUID Subsystem NQN Current max replicas Supported max replicas MinVersionInCluster MinAllowedVersion MaxAllowedVersion

2ac0b5f1-e332-4526-9799-e5cec2208837 nqn.2016-01.com.lightbitslabs:uuid:1fa41a41-cf47-4ebd-b0f4-babda5fe322c 3 3 2.3.12~b793 2.3.X

Connect to the volume from a client to see the SSD device.

Connect to the volume to attach the SSD device to the client (this can be executed with a simple ‘for’ loop as well).

LIGHTBITS_CONTROLLER_IPS="172.16.231.70 172.16.231.71 172.16.231.72"; for CONTROLLER_IP in $LIGHTBITS_CONTROLLER_IPS; do nvme connect -t tcp -a $CONTROLLER_IP --ctrl-loss-tmo -1 -n $LIGHTBITS_CLUSTER_NQN -s 4420 -q $VOLUME_ACL; done

Check volumes are mapped

lsblk

Sample Output

root@rack07-server56:~ lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT

nvme0n1 259:1 0 50G 0 disk

sda 8:0 0 111.8G 0 disk

|-sda2 8:2 0 1G 0 part /boot

|-sda3 8:3 0 110.8G 0 part

| |-inaugurator--v2-osmosis--cache 253:1 0 30G 0 lvm

| |-inaugurator--v2-root 253:2 0 58.2G 0 lvm /

| `-inaugurator--v2-swap 253:0 0 8G 0 lvm [SWAP]

`-sda1

Mount the SSD device to a mounting point on the client.

Make sure the e2fsprogs package is installed. If not: yum install e2fsprogs.

# Create directory to mount snapshot

root@rack07-server56:~ mkdir /tmp/snapshot

# Format device to ext4

root@rack07-server56:~ mkfs.ext4 /dev/nvme0n1

# Mount volume

root@rack07-server56:~ mount /dev/nvme0n1 /tmp/snapshot

# Check mount

root@rack07-server56:~ df -h

Filesystem Size Used Avail Use% Mounted on

devtmpfs 32G 0 32G 0% /dev

/dev/nvme0n1 25G 45M 24G 1% /tmp/snapshot

Put some data into the mounted SSD disk.

Create a file using the dd command:

# Move to working directory

root@rack07-server56:~ cd /tmp/snapshot

# Add data

root@rack07-server56:/tmp/snapshot dd if=/dev/zero of=1g_sample_file.txt bs=4096 count=256000

# Check file content

root@rack07-server56:/tmp/snapshot ll -h

-rw -r--r--. 1 root root 1000M Mar 2 10:32 1g_sample_file.txt

From the Lightbits server, create a snapshot of the initial volume.

# Create snapshot

root@rack03-server72:~ lbcli create snapshot --name=snapshot1 --project-name=default --source-volume-name=vol1

# Check snapshot is available

root@rack03-server72:~ lbcli list snapshots --project-name=default

Name UUID Source volume UUID

snapshot1 ca6e5578-3289-4c03-8445-f035189698c3 01b20f49-13d6-468f-b82d-752594922a6e

Put more data from the client side to the mounted disk.

# Add data

root@rack07-server56:/tmp/snapshot dd if=/dev/zero of=1g_sample_file2.txt bs=4096 count=256000

# Check file content

root@rack07-server56:/tmp/snapshot ll -h

-rw -r--r--. 1 root root 1000M Mar 2 10:32 1g_sample_file.txt

-rw -r--r--. 1 root root 1000M Mar 2 11:35 1g_sample_file2.txt

Create a clone from the snapshot that was created.

root@rack03-server72:~ lbcli create volume --name=clone_snap1 --source-snapshot-uuid=ca6e5578-3289-4c03-8445-f035189698c3 --acl="acl3" --replica-count=1 --size="25 Gib" --project-name=default

Name UUID State Protection State NSID

Size Replicas Compression ACL Rebuild Progress

clone_snap1 30242a3b-cf7d-4a1e-ae0c-14295b631ebf Creating Unknown 0 25 GiB 1 false values:"acl3"

Connect to the clone and verify that it holds only the initial data.

If the same ACL is used, the cloned SSD disk should be attached automatically on the client.

root@rack07-server56:~ lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT

nvme0n1 259:1 0 25G 0 disk /tmp/snapshot

nvme0n2 259:3 0 25G 0 disk

Mount the clone to a different directory

# Create mount point

root@rack07-server56:~ mkdir /tmp/clone

# Mount volume

root@rack07-server56:~ mount /dev/nvme0n2 /tmp/clone

Check mounts

root@rack07-server56:~ df -h

/dev/nvme0n1 25G 3.0G 21G 13% /tmp/snapshot

/dev/nvme0n2 25G 1.1G 23G 5% /tmp/clone

See that only the original sample file exists before the snapshot was taken

# Move to clone directory

root@rack07-server56:~ cd /tmp/clone

# Check contents of clone volume

root@rack07-server56:/tmp/clone ll -h

total 1024004

-rw -r--r--. 1 root root 1048576000 Mar 2 10:32 1g_sample_file.txt

Roll back a volume to the snapshot, and verify that its contents now only have the file that was created before taking the snapshot.

The rollback operation takes a volume and restores it back to a snapshot state (data + md). It is recommended to either remove active mounts, detach the volume, or flush caches before performing this operation.

The process should be as follows:

Stop process/es that use the volume.
Unmount FS create on top of the volume; e.g., for mount point /mnt/volumetorollback.a. Unmount /mnt/volumetorollback.
Perform rollback via lbcli.
Mount the volume: mount /mnt/volumetorollback.

Unmount the device from the mount point:

root@rack07-server56:~ umount -l /tmp/snapshot

umount: /dev/nvme0n1: not mounted

Check the UUID of the snapshot, and of the volume you would like to roll back:

# List volumes

root@rack03-server72:~ lbcli list volumes

Name UUID State Protection State NSID Size Replicas Compression ACL Rebuild Progress

vol1 01b20f49-13d6-468f-b82d-752594922a6e Available FullyProtected 2 25 GiB 1 false values:"acl3" None

clone_snap1 30242a3b-cf7d-4a1e-ae0c-14295b631ebf Available FullyProtected 3 25 GiB 1 false values:"acl3" None

# List snapshots

root@rack03-server72:~ lbcli list snapshots --project-name=default

Name UUID Source volume UUID State

snapshot1 ca6e5578-3289-4c03-8445-f035189698c3 01b20f49-13d6-468f-b82d-752594922a6e Available

To roll back the volume to the snapshot, run:

root@rack03-server72:~ lbcli rollback volume --project-name=default --src-snapshot-uuid=ca6e5578-3289-4c03-8445-f035189698c3 --uuid=01b20f49-13d6-468f-b82d-752594922a6e

Mount the volume again from the client side, and verify that only one file is there:

# Mount volume

root@rack07-server56:~ mount /dev/nvme0n1 /tmp/snapshot

# Check only original file exists

root@rack07-server56:~ ll -h /tmp/snapshot

total 1024004

-rw -r--r--. 1 root root 1048576000 Mar 2 10:32 1g_sample_file.txt

Create a snapshot-policy:

# Flags meaning

root@rack03-server72:~ lbcli create snapshots-policy --help

--days-in-cycle int Days in cycle for daily schedule policy (required if

hours-in-cycle wasn't provided) (default -1)

--description string Policy description

--hours-in-cycle int Hours in cycle for hourly schedule policy (required if

days-in-cycle wasn't provided) (default -1)

--name string Policy name (required)

--project-name string Project name (required)

--retention-time string Retention time will determine for how long to keep the

snapshots

--start-time string Schedule start time. It must be in the form of HH:MM , in

which HH is 00-23 and MM is 00-59

--volume-name string Volume name to assign policy to (required if volume -uuid

wasn't provided)

--volume-uuid string Volume UUID to assign policy to (required if volume -name

root@rack03-server72:~ lbcli create snapshots-policy --project-name=default --name=policy1 --volume -uuid=a7f67ad0-1f3d-49cb-9650-b82042378014 --description="my policy" --hours-in-cycle=2 --start-time=22:00 --retention-time=4h

Name UUID Volume Name State Type

policy1 3c03b2bf-e102-4c6c-8c6d-173224148f31 vol1 Creating Hourly

List snapshot-policies:

root@rack03-server72:~ lbcli list snapshots-policies --project-name=default --volume-uuid=a7f67ad0-1f3d-49cb-9650-b82042378014

Name UUID Volume Name State Type

policy1 3c03b2bf-e102-4c6c-8c6d-173224148f31 vol1 Active Hourly

Get snapshot-policies:

root@rack03-server72:~ lbcli get snapshots-policy --project-name=default --uuid=3c03b2bf-e102-4c6c-8c6d-173224148f31 -o json

{

"UUID": "3c03b2bf-e102-4c6c-8c6d-173224148f31",

"name": "policy1",

"resourceUUID": "a7f67ad0-1f3d-49cb-9650-b82042378014",

"resourceName": "vol1",

"projectName": "default",

"schedulePolicy": {

"snapshotSchedulePolicy": {

"hourlySchedule": {

"startTime": "2021-03-08 T22:16:21Z",

"hoursInCycle": 2

}

"retentionTime": "14400s"

"description": "my policy",

"state": "Active"

}

Rollback volume:

root@rack03-server72:~ lbcli rollback volume --project-name=default --src-snapshot-uuid=bd52d3d8-65a5-49fe-a934-b7d8b07ef040 --uuid=05f49718-4897-4ff5-adb9-5d7ccd6fc138

Delete snapshots/snapshot-policy:

# Delete snapshot

root@rack03-server72:~ lbcli delete snapshot --project-name=default --uuid=bd52d3d8-65a5-49fe-a934-b7d8b07ef040

# Delete snapshot policy

root@rack03-server72:~ lbcli delete snapshots-policy --project-name=default --uuid=3c03b2bf-e102-4c6c-8c6d-173224148f31

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