Understanding a Volume Location in the Lightbits Cluster

You can use the lbcli get volume command to see which node in the cluster holds the data of a specific volume. Note that volume placement could change during the lifecycle of a volume, due to dynamic rebalancing.

Sample Command

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$ lbcli -J $LIGHTOS_JWT get volume --uuid=48dbbe54-1548-4444-866e-6438d4877e5f​(Project Admin should add the --project-name=<project-name>)
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Sample Output

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name: vol_3rebuildProgress: NoneUUID: 48dbbe54-1548-4444-866e-6438d4877e5fAcl:    Values:    - hostnqn1nsid: 4size: "107374182400"nodeList:- 9a625dbf-de1b-4211-b9d3-0bdf70faa5f5- 9f1a3a85-5be5-4f98-a44e-4271fbdbe7cc- a7f67ad0-1f3d-49cb-9650-b82042378014protectionState: FullyProtectedreplicaCount: 3state: Created
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You can also run the nvme list-subsys command on the application server, on a specific block-device that corresponds to a volume on the cluster.

Sample Command

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# nvme list-subsys nvme0n1
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Sample Output

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nvme-subsys0 -NQN=nqn.2014-08.org.nvmexpress:NVMf:uuid:b550533c-8bb0-46df-9019-cd4c25c6e6e7\ +- nvme0 tcp traddr=10.18.38.4 trsvcid=4420 live  +- nvme1 tcp traddr=10.18.38.5 trsvcid=4420 live  +- nvme2 tcp traddr=10.18.38.7 trsvcid=4420 live inaccessible +- nvme3 tcp traddr=10.18.38.8 trsvcid=4420 live optimized +- nvme4 tcp traddr=10.18.38.29 trsvcid=4420 live inaccessible
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This command’s output includes the cluster’s primary node (optimized) IP address for the volume, the secondary node (inaccessible) IP address, and the other nodes that do not hold data for that volume (block device nvme0n1).

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