Storage discovery examples

  • Release version: Yokohama
  • Updated January 30, 2025
  • 2 minutes to read
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    Summary of Storage discovery examples

    ServiceNow Discovery automatically identifies and creates configuration items (CIs) and relationships for physical and logical storage components connected to application and database servers. It supports direct attached storage (DAS) and multipath fibre channel storage area networks (SAN), helping you maintain an accurate and detailed configuration management database (CMDB).

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    Direct Attached Storage (DAS)

    Discovery detects SCSI drives attached directly to Linux hosts, including partitions and logical volumes managed by Logical Volume Management (LVM). For example, a SCSI device with bootable and storage pool partitions is discovered with the following key CIs and relationships:

    • Physical storage device: Represented as SCSI disk CIs.
    • Partitions: Each partition is identified, including details such as mount points and file systems (e.g., Ext4).
    • Logical volumes and storage pools: LVM-managed volumes and storage pools are mapped and linked to their physical partitions.

    This detailed mapping ensures visibility of storage utilization and structure, such as boot partitions and storage pools mounted on the Linux root file system.

    Multipath Fibre Channel Storage

    Discovery supports SAN environments where multiple physical storage devices are connected via fibre channel switched fabrics, providing failover through redundant paths. Key capabilities include:

    • Identifying multiple physical storage devices connected through fibre switches.
    • Discovering partitions and logical volumes mapped across multiple physical devices.
    • Capturing mount points and file system details for logical volumes on Linux hosts.
    • Creating CIs for host bus adapters (HBAs) and physical block storage components.
    • Establishing relationships within fibre channel switched fabrics, showing redundant connectivity paths for failover and high availability.

    Key Outcomes

    • Comprehensive storage visibility: Understand the complete storage topology from physical disks through partitions, logical volumes, and file systems.
    • Accurate CMDB population: Automatically build and maintain detailed CIs and relationships reflecting storage infrastructure and multipath configurations.
    • Improved infrastructure management: Enable better impact analysis, troubleshooting, and capacity planning through precise storage component mapping.
    • Support for failover environments: Capture fibre channel fabric redundancy to support high availability and disaster recovery planning.

    Discovery creates configuration items (CI) and CI relationships for physical and logical storage components attached directly to application and database servers or by fibre channel switched fabric in a multi-path configuration.

    Direct attached storage

    In this example of direct attached storage (DAS), a SCSI drive with two partitions, /dev/sda1 and /dev/sda2, is attached to a Linux host. The /dev/sda1 partition is bootable and supports the system software. The /dev/sda2 partition contains a logical volume configured as a storage pool and mounted to the Linux root file system by Logical Volume Management (LVM). The storage pool uses only 1.5GB of the partition, leaving 13GB of storage available for additional logical volumes.
    Figure 1. Direct attached storage example
    Direct attached storage DAS example
    Table 1. CIs and relationships created for direct attached storage (DAS)
    Configuration item Description Tables Key reference and Relationships
    /dev/sda SCSI physical storage device
    • [cmdb_ci_disk]
    • [cmdb_ci_storage_device]
    • [cmdb_rel_ci]
    		 [cmdb_rel_ci]
    • Provides: /dev/sda
    • Provided by:/dev/sda1
    [cmdb_rel_ci]
    • Provides: /dev/sda
    • Provided by:/dev/mapper/lvm-root-333-0
    /dev/sda1 Partition 1 on the SCSI storage device
    • [cmdb_ci_partition]
    • [cmdb_ci_storage_volume]
    • [cmdb_ci_file_system]
    • [cmdb_rel_ci]
    		 [cmdb_ci_file_system]
    • Mount point: /boot
    • File system: Ext4
    [cmdb_rel_ci]
    • Provides: /dev/sda
    • Provided by:/dev/sda1
    /dev/sda2 Partition 2 on the SCSI storage device
    • [cmdb_ci_partition]
    • [cmdb_ci_storage_pool_member]
    		 [cmdb_ci_storage_pool_member]
    • Pool: /dev/mapper/lvm-root-333-0
    • Storage: /dev/sda2
    /dev/mapper/lvm-root-333-0 Linux logical volume, mapped with LVM to a physical disk storage partition.
    • [cmdb_ci_storage_device]
    • [cmdb_ci_storage_volume]
    • [cmdb_ci_file_system]
    • [cmdb_ci_storage_pool]
    • [cmdb_ci_storage_pool_member]
    • [cmdb_ci_lvm_pool]
    • [cmdb_ci_lvm_pool_member][cmdb_rel_ci]
    		 [cmdb_ci_file_system]
    • Mount point: /
    • File system: Ext4
    [cmdb_rel_ci]
    • Provides: /dev/sda
    • Provided by:/dev/mapper/lvm-root-333-0
    [cmdb_ci_storage_pool_member]
    • Pool: /dev/mapper/lvm-root-333-0
    • Storage: /dev/sda2

    Multipath fibre channel storage

    In this example of a fibre channel storage area network (SAN), two physical storage devices, mpatha and mpathb, are attached to a Linux host through fibre switches, which provide failover capabilities. The mpatha drive contains two partitions, mpatha1 and mpatha2. The first partition is mounted directly to /boot on the Linux host. Three logical volumes are mapped to the mpatha2 partition and to the physical device mpathb. The logical volumes are mounted as Ext4 file systems in folders on the Linux root structure. This example shows the CIs that Discovery manages for each component and the mounting points for the logical volumes on the Linux host.

    Figure 2. Multipath fibre channel storage example
    Multipath fibre channel storage example

    Switched fibre fabric details

    Discovery creates CIs for the logical sub-components in NAS and SAN environments, such as fibre channel disks and pool components, as well as for host bus adapters (HBA) and physical block storage. In multipath environments, Discovery creates CI relationships within the switched fibre fabrics that connects the Linux host to the physical storage devices. In this diagram, the fibre fabrics have redundant paths that the SAN environment can use for failover if connections fail.

    Figure 3. Fibre fabric redundant paths
    Fibre fabric redundant paths