Version 9.0(1) - 9.1(x)
Notes on PAWS-M VM configurations
IOPS and Storage System Performance Requirements

Version 9.0(1) - 9.1(x)

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Notes on PAWS-M VM configurations

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For Small or Small Plus TRCs, or for Specs-based servers with a Restricted UC Performance CPU, use UCM 1K user VM configuration as the "Small ELM" or "Small PAWS-M" capacity point.

For all other TRCs, and for Specs-based servers with a Full UC Performance CPU, use the UCM 2.5K user VM configuration as the "Medium/Large ELM" or "Medium/Large PAWS-M" capacity point.

IOPS and Storage System Performance Requirements

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This section provides the IOPS data for a Cisco Unified Communications Manager system under load. These values are per active VM. Which VMs are active, and how many are active simultaneously, depends on how the CUCM cluster nodes are setup with respect to service activation, redundancy groups, etc. (see www.cisco.com/go/ucsrnd for details).

93-98% ot total IO is "sequential writes" with an IO block size of 4 kilobytes.

• Active call processing: As a reference, the following steady state IOPS were observed at various loads (expressed in Busy Hour Call Attempts):
  • 10K BHCA produces ~ 35 IOPS
  • 25K BHCA produces ~ 50 IOPS
  • 50K BHCA produces ~ 100 IOPS
  • 100K BHCA produces ~ 150 IOPS
• Software upgrades during business hours generate 800 to 1200 IOPS in addition to steady state IOPS.
• CDR/CMR via CDR Analysis and Reporting (CAR)
  • CUCM sending CDR/CMR to the external billing server does not incur any additional IOPS.
  • Enabling CAR continuous loading results in around 300 IOPS average on the system.
  • Scheduled uploads are around 250 IOPS for Publisher's VM only.
• Trace collection is 100 IOPS (occurs on all VMs for which tracing is enabled).
• Nightly backup (usually Publisher's VM only) is 50 IOPS