Virtual machine instrumentation categories

IBM Spectrum Protect™ virtual machine (VM) instrumentation reports the elapsed times for many process categories.

The following table lists the virtual machine instrumentation categories that are tracked and the activity that is timed.

Table 1. Virtual machine instrumentation categories
Category Activity
VM Snapshot Time that is spent generating and removing a VM guest snapshot by using the VMware Infrastructure Software Development Kit (VI SDK). Some of the work is completed asynchronously, for example, snapshot delete.
VM Send Data Time that is spent sending data to the IBM Spectrum Protect server. Data processing includes client-side data deduplication and the Network Send phase.
VM Get Data Time that is spent retrieving data from the IBM Spectrum Protect server. This category includes the following activities:
  • Retrieving control files from the IBM Spectrum Protect server during incremental backup.
  • Buffering data that is received during VM guest restore, and is then written out by using VM I/O writes to VMware.
VM Query Time that is spent querying the IBM Spectrum Protect server to determine the following:
  • Whether data deduplication and compression, or both, are enabled.
  • Whether file space queries for nodes on virtual machines are used.
VM Query VE Time that is spent querying whether VMware VM guest disks are changed. This category uses the VMware VI SDK to identify a set of changed blocks.
VM Assign Time that is spent assigning file groups to the IBM Spectrum Protect server, by using the dsmGroupHandler function.
VM VCM Lock Time that is spent locking a semaphore during Volume Control Manager (VCMLIB) API calls. The time is spent on the following functions:
  • Locking for volume control data reads or updates
  • Manipulating data by block control
  • Retrieving megablocks in a volume
VM Transaction Time that is spent processing transactions with the IBM Spectrum Protect server.
VM I/O Time that is spent reading and writing data to and from the VIX Disk Library for Virtual Disk Development Kit (VDDK) disks for a VM. Performance can vary depending on whether thin or thick-provisioned disks are used and if the disks are lazy zeroed.
VM Control File I/O Time that is spent reading and writing VM guest control (CTL) files during VM guest backup and restore operations.
Thread Wait Time that is spent opening and closing VDDK disks on IBM Spectrum Protect for Virtual Environments clients.

Opening and closing of VM disks is serialized for an IBM Spectrum Protect client instance. The time that it takes to open and close the VM disks includes mounting the disk on the client or proxy system.