Chapter 3 Statistics and Datasets
Determining the impact of a dynamic statistic
Capacity: Capacity Percent Used
Capacity System Pool Bytes Used
Capacity: System Pool Bytes Used
Capacity System Pool Percent Used
Capacity: System Pool Percent Used
Data Movement NDMP Bytes Statistics
Data Movement: NDMP Bytes Statistics
Data Movement NDMP Operations Statistics
Data Movement: NDMP Operations Statistics
Data Movement Replication Bytes
Data Movement: Replication Bytes
Data Movement Replication Operations
Data Movement: Replication Operations
Data Movement Shadow Migration Bytes
Data Movement: Shadow Migration Bytes
Data Movement Shadow Migration Ops
Data Movement: Shadow Migration Ops
Data Movement Shadow Migration Requests
Data Movement: Shadow Migration Requests
Protocol Fibre Channel Operations
Protocol: Fibre Channel Operations
Protocol: HTTP/WebDAV Requests
Data Movement NDMP Bytes Transferred to/from Disk
Data Movement: NDMP Bytes Transferred to/from Disk
Data Movement NDMP Bytes Transferred to/from Tape
Data Movement: NDMP Bytes Transferred to/from Tape
Data Movement NDMP File System Operations
Data Movement: NDMP File System Operations
Data Movement Replication Latencies
Data Movement: Replication Latencies
Disk ZFS Logical I/O Operations
Disk: ZFS Logical I/O Operations
Memory Kernel Memory Lost to Fragmentation
Memory: Kernel Memory Lost to Fragmentation
The CPUs statistic is used to display the heat map for CPUs broken down by percent utilization. This is the most accurate way to examine how CPUs are utilized.
When investigating CPU load, after checking the utilization average from CPU Percent Utilization.
This statistic is particularly useful for identifying if a single CPU is fully utilized, which can happen if a single thread is saturated with load. If the work performed by this thread cannot be offloaded to other threads so that it can be run concurrently across multiple CPUs, then that single CPU can become the bottleneck. This will be seen as a single CPU stuck at 100% utilization for several seconds or more, while the other CPUs are idle.
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CPU utilization includes the time to process instructions (that are not part of the idle thread); which includes memory stall cycles. CPU utilization can be caused by:
executing code (including spinning on locks)
memory load
Since the appliance primarily exists to move data, memory load often dominates. So a system with high CPU utilization may actually be high as it is moving data.