Device group metrics

Unisphere collects and displays metrics for device groups.

Within the PM metrics section, V4 is used to denote that the metric is supported only by a storage system (array) running PowerMaxOS 10 (6079). V3 is used to denote that the metric is supported only by a storage system (array) running HYPERMAX OS 5977 or PowerMaxOS 5978. Metrics without the denotation are supported by all storage systems (arrays).

The following table lists all metrics that are available for device groups.

Table 1. Device group metrics

Metric	Description
% Hit	The percentage of I/O operations that were immediately satisfied from cache
% Miss	The percentage of I/O operations that were misses
% Random IO	The percentage of I/O operations that were random
% Random Read Hit	Calculated value: 100 * (random read hits per sec/total I/Os per sec).
% Random Read Miss	Calculated value: 100 * (random read misses per sec/total I/Os per sec).
% Random Reads	The percentage of all read I/Os that were random.
% Random Write Hit	Calculated value: 100 * (random write hits per sec/total I/Os per sec).
% Random Write Miss	Calculated value: 100 * (random write misses per sec/total I/Os per sec).
% Random Writes	The percentage of all write I/Os that were random
% Read Hit	The percentage of read operations, performed by the group, that were immediately satisfied by cache.
% Read Miss	The percentage of read miss operations performed each second by the group. A miss occurs when the requested read data is not found in cache.
% Reads	The percentage of I/O operations that were reads
% Seq Read	Calculated value: 100 * (seq reads per sec/total I/Os per sec).
% Seq Read Hit	The percentage of the sequential read operations that were immediately satisfied from cache.
% Seq Read Miss	The percentage of the sequential read operations that were misses.
% Seq Write Hit	The percentage of the sequential write operations that were immediately satisfied from cache.
% Seq Write Miss	The percentage of the sequential write operations that were misses.
% Seq Writes	Calculated value: 100*(seq writes per sec/total I/Os per sec).
% Sequential IO	Calculated value: 100 * (total seq I/Os per sec/total I/Os per sec)
% Write Hit	The percentage of write operations, performed by the group, that were immediately satisfied by cache.
% Write Miss	The percentage of write miss operations performed each second by the group. A miss occurs when the write operation had to wait while data was destaged from cache to the disks.
% Writes	The percentage of I/O operations that were writes
Allocated Capacity	The allocated capacity of the device group
Avg IO Size	Calculated value: (HA Kbytes transferred per sec/total I/Os per sec)
Avg Read Size	Calculated value: (Kbytes read per sec/total reads per sec)
Avg Write Size	Calculated value: (Kbytes written per sec/total writes per sec)
Avg. Write Paced Delay (ms)	Average write paced delay (milliseconds) (V3).
BE % Reads	The percent of the back-end I/O that were read requests.
BE % Writes	The percent of the back-end I/O that were write requests.
BE Optimize Write Throughput	Internal metric
BE Partial Sector Writes (KB)	The kilobytes of back-end I/O that were partial sector writes (V3)
BE Prefetched Throughput	The number of MBs prefetched from disk to cache in a second.
BE Prefetched Tracks Used/sec	The number of prefetched tracks used each second from the disk directors to the cache.
BE Prefetched Tracks/sec	The total prefetched tracks each second from the disk directors to the cache.
BE RDF Copy Throughput	Internal metric
BE RDF Copy/sec	Internal metric
BE Read Reqs/sec	The number of read requests each second performed by the disk directors to cache.
BE Read Throughput For Copy	BE Read Throughput For Copy
BE Reads For Copy/sec	Internal metric
BE Reqs/sec	The number of read/write requests each second performed by the disk directors to cache.
BE Throughput Read	BE Throughput Read
BE Throughput Transferred	BE Write Throughput Transferred
BE Throughput Written	BE Throughput Written
BE Write Reqs/sec	The number of write requests each second performed by the disk directors to cache.
BE Write Throughput For Copy	BE Write Throughput for copy
BE Write Throughput For Rebuild	BE Write Throughput for rebuild.
BE Writes For Copy/sec	Internal metric
BE Writes For Rebuild/sec	Internal metric
Device Block Size	The block size of the volume
Host Hits/sec	The number of host read/write operations performed each second by the group that were immediately satisfied from cache.
Host lOs/sec	The number of host operations performed each second by the group.
Host Misses/sec	The number of host read/write operations performed each second by the group that could not be satisfied from cache.
Host Read Hits/sec	The number of host read operations performed each second by the group that were immediately satisfied from cache.
Host Read Misses/sec	The number of host read operations performed each second by the group that were not satisfied from cache.
Host Reads/sec	The number of host read operations performed each second by the group.
Host Throughput	The cumulative number of host MBs read/writes per second by the group.
Host Throughput Read	The cumulative number of host MBs read per second by the group
Host Throughput Written	The cumulative number of host MBs written per second by the group
Host Write Hits/sec	The number of host write operations performed each second by the group that were immediately satisfied from cache.
Host Write Misses/sec	The number of host write operations performed each second by the group that were not satisfied from cache.
Host Writes/sec	The number of host write operations performed each second by the group.
IO Density	The number of BE requests per GB of disk.
Max WP Capacity Threshold	The capacity of the maximum number of write-pending slots available
Max WP Threshold	The maximum number of write-pending slots available for the group
Random IOs/sec	I/Os from a host that is not identified as part of a sequential stream
Random Read Hits/sec	Random read I/O that were satisfied from the cache
Random Read Misses/sec	Random read I/O that were misses
Random Reads/sec	Read I/O commands from a host that is not identified as part of a sequential stream.
Random Write Hits/sec	Random write I/Os that were immediately placed in cache because space was available.
Random Write Misses/sec	Random write I/Os that were misses.
Random Writes/sec	Write I/O commands from a host that is not identified as part of a sequential stream.
RDF Reads/sec	Total SRDF reads per second for the device group.
RDF Response Time	The SRDF round-trip time - the metric is calculated as follows: SRDF Accumulated Service Time/(SRDF Reads/sec + SRDF Writes/sec) rolled up from the SRDF devices in the group
RDF Rewrites/sec	SRDF rewrites per second.
RDF MBs Read/sec	SRDF MBs reads per second.
RDF Throughput Read	SRDF MBs written per second
RDF Throughput Written	Total SRDF writes per second for the device group.
RDF/S Write RT	A summary of the read, write, and average response times for the selected SRDF/S group.
Read Miss RT	The average time that it took the storage system to serve one read miss I/O for this group.
Read RT	The average time that it took the storage system to serve one read I/O for this group.
Response Time	The average time that it takes to satisfy I/O requests.
Seq lOs/sec	Number of I/O operations performed each second that were sequential.
Seq Read Hits/sec	Number of sequential read operations performed each second by the group that were immediately satisfied from cache.
Seq Read Miss/sec	Number of sequential read operations performed each second by the group that were misses
Seq Reads/sec	Number of read I/O operations performed each second that were sequential.
Seq Write Hits/sec	Number of sequential write operations performed each second by the group that were immediately satisfied from cache.
Seq Write Misses/sec	Number of sequential write operations performed each second by the group that were misses.
Seq Writes/sec	Number of write I/O operations performed each second that were sequential.
Total Capacity	The total capacity of the device group
WP Count	The number of tracks in write pending mode for the group.
WP Used Capacity	The WP used capacity
Write Miss RT	The average time that it took the storage system to serve one write miss I/O for this group.
Write Paced Delay (ms)	Write paced delay (milliseconds) (V3).
Write RT	The average time that it took the storage system to serve one write I/O for this group.