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Version: 3.1

Add a dedicated journal device to a node

A journal device is a dedicated storage component used to improve the performance and reliability of write operations. It logs write operations before they are finalized in the main storage volumes. This page outlines how to configure a Portworx StorageCluster to add a journal device to a new or existing node.

Prerequisites​

Before proceeding, ensure that:

  • The chosen journal device matches or surpasses the performance of the data pool devices.
  • Your setup does not use PX-StoreV2 backend.
  • The selected device or a partition on the selected device is not being used by any other service or applications.

Check your current journal device configuration​

Before you begin, you may already have a journal device configured for your cluster. If you're unsure, you can check the current journal device configuration by running the pxctl status command and finding the Journal Device section:

pxctl status
...
    Journal Device: 
    1   /dev/sdb1   STORAGE_MEDIUM_SSD  3.0 GiB
    ...

Add a journal device to a new node automatically​

You can add a journal device to a new node automatically by editing your Portworx StorageCluster. Using this method, Portworx creates a partition from the existing storage pool drives:

storage:
    useAll: true
    journalDevice: auto
caution

You cannot use this method to add a journal device existing nodes.

Add journal device manually​

You can use this method to add a journal device to a new or existing node manually. Done in this way, Portworx creates a journal device out of a drive, cloud drive, or partition you provide it.

Add journal device to a new node​

Follow the steps in this section to edit your Portworx StorageCluster to add the size and type of the journal device you want to add for your environment.

  1. Run the command to edit your Portworx StorageCluster:

    kubectl edit stc <px-cluster-ID> -namespace <px-namespace>

  2. Add the journalDeviceSpec parameter and specify the type and size of the device:

    spec:
        cloudStorage:
            deviceSpecs:
            - type=pd-standard,size=150
            journalDeviceSpec: type=<device-type>,size=<device-size>

  3. After you add a storage node, run the following command on a node to verify that a journal device is added:

    Status: PX is operational
    Telemetry: Disabled or Unhealthy
    Metering: Disabled or Unhealthy
    License: Trial (expires in 31 days)
    Node ID: 5990262c-aeb0-4404-a5f1-6ccfb5c6b80a
       IP: 10.13.158.150 
       Local Storage Pool: 1 pool
       POOL    IO_PRIORITY     RAID_LEVEL   USABLE  USED    STATUS  ZONE    REGION
       0    HIGH        raid0       384 GiB 12 GiB  Online  default default
       Local Storage Devices: 3 devices
       Device   Path        Media Type          Size        Last-Scan
       0:1     /dev/sdf    STORAGE_MEDIUM_SSD   128 GiB     31 Jan 24 02:26 UTC
       0:2     /dev/sdd    STORAGE_MEDIUM_SSD   128 GiB     31 Jan 24 02:26 UTC
       0:3     /dev/sde    STORAGE_MEDIUM_SSD   128 GiB     31 Jan 24 02:26 UTC
       total            -           384 GiB
       Cache Devices:
       * No cache devices
       Journal Device: 
       1    /dev/sdb1   STORAGE_MEDIUM_SSD  3.0 GiB
       Metadata Device: 
       1    /dev/sdc    STORAGE_MEDIUM_SSD  64 GiB
    Cluster Summary
       Cluster ID: PX-xxx-0377
       Cluster UUID: 847373dd-xxxx
       Scheduler: none
       Total Nodes: 3 node(s) with storage (3 online)
       IP           ID                                    SchedulerNodeName   Auth      StorageNode    Used    Capacity     Status  StorageStatus   Version             Kernel                        OS
       10.xx.xxx    b0e40a2e-2e99-4f0d-817b-4c988d5af111    N/A              Disabled          Yes      12 GiB  384 GiB     Online  Up              3.1.0.0-0a8098d   3.10.0-1160.80.1.el7.x86_64   CentOS Linux 7 (Core)
       10.xx.xxx    aa07c3ce-2475-4542-96c8-b06882d44629    N/A              Disabled          Yes      12 GiB  384 GiB     Online  Up              3.1.0.0-0a8098d   3.10.0-1160.80.1.el7.x86_64   CentOS Linux 7 (Core)
       10.xx.xxx    5990262c-aeb0-4404-a5f1-6ccfb5c6b80a    N/A              Disabled          Yes      12 GiB  384 GiB     Online  Up (This node)  3.1.0.0-0a8098d   3.10.0-1160.80.1.el7.x86_64   CentOS Linux 7 (Core)

    You will see the journal device details in the status.

Add a journal device to an existing node​

info

This workflow is not supported in a disaggregated cloud deployment. Contact the support team if your setup is disaggregated in a cloud environment.

To add a journal device to an existing node, follow the steps in this section:

  1. Switch the node to pool maintenance mode:

    pxctl service pool maintenance --enter
    This is a disruptive operation, PX will restart in maintenance mode.
    Are you sure you want to proceed ? (Y/N): Y

    Respond with Y when prompted.

  2. Confirm that the node is in pool maintenance mode:

    pxctl status
    Status: PX storage in pool maintenance
    Telemetry: Disabled or Unhealthy
    Metering: Disabled or Unhealthy
    License: PX-Enterprise (floating) (lease renewal in 6h, 4m)
    Node ID: db636a43-894e-4d09-8268-f739ed673990
        IP: 10.xx.xxx.xxx 
        Local Storage Pool: 1 pool
        POOL    IO_PRIORITY RAID_LEVEL  USABLE  USED    STATUS      ZONE    REGION
        0   HIGH        raid0       2.0 TiB 1.0 TiB In Maintenance  default default
        Local Storage Devices: 2 devices
        Device  Path        Media Type      Size            Last-Scan
        0:1 /dev/sdc    STORAGE_MEDIUM_SSD  1021 GiB        15 Dec 23 15:02 UTC
        0:2 /dev/sdd    STORAGE_MEDIUM_SSD  1.0 TiB         15 Dec 23 15:02 UTC
        total           -           2.0 TiB
    Cluster Summary
        Cluster ID: PX-xxx
        Cluster UUID: 3a38fa3d-2d5f-4d5b-92de-2b9a5f67ba0e
        Scheduler: none
        Total Nodes: 9 node(s) with storage (8 online)
        IP              ID                                     SchedulerNodeName    Auth        StorageNode Used        Capacity    Status          StorageStatus         Version           Kernel                       OS
        10.xx.xxx.xxx   ff27a278-c38d-4383-957c-e4e9916fcde5    N/A                 Disabled    Yes         879 GiB     2.0 TiB     Online          Up                    3.1.0.0-4375431   4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
        10.xx.xxx.xxx   f983aa93-3f67-43cc-b9ae-746abe26a72b    N/A                 Disabled    Yes         531 GiB     2.0 TiB     Online          Up                    3.1.0.0-4375431   4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
        10.xx.xxx.xxx   db636a43-894e-4d09-8268-f739ed673990    N/A                 Disabled    Yes         20 GiB      350 GiB     In Pool Maintenance Down (This node)  3.1.0.0-4375431   4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
        10.xx.xxx.xxx   b9b21a35-ae3a-4217-a898-312cb721e64f    N/A                 Disabled    Yes         1.0 TiB     2.0 TiB     Online          Up                    3.1.0.0-4375431   4.20.13-1.el7.elrepo.x86_64 CentOS Linux 7 (Core)
        ...

    You should see a status output indicating that the node is in pool maintenance mode.

  3. Add the journal device. It is recommended to use an SSD/NVME for this purpose:

    pxctl service drive add --drive /dev/nvme01 --journal
    Successfully added journal device /dev/nvme010p1

  4. Exit the pool maintenance mode: 

    pxctl service pool maintenance --exit
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