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# Thin Volume metrics

Unisphere collects and displays metrics for thin volumes.

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 thin volumes.

Table 1. Thin volume metrics
Metric | Description
--- | ---
% Hit | The percent of operations that were immediately satisfied by cache
% Miss | The percent of operations that were misses. A miss occurs when the operation cannot be immediately satisfied from cache because the data is not there or the operation has to wait while data is de-staged from cache to disks.
% PowerPath Observed Relative RT | Ratio of PowerPath Response Time to FA Response Time, as a percentage
% Random IO | The percent 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 percent of I/O that is random reads.
% 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 percent of write commands from a host that is not identified as part of a sequential stream.
% Read Hit | The percentage of read operations, performed by the volume, that were immediately satisfied by cache.
% Read Miss | The percentage of read miss operations performed each second by the volume. A miss occurs when the requested read data is not found in cache or the write operation had to wait while data was destaged from cache to the disks.
% Reads | The percentage of I/Os operations that were reads
% Seq Read | Calculated value: 100 * (seq reads per sec/total I/Os per sec).
% Seq Read Hit | The percent of the sequential read operations that were immediately satisfied from cache.
% Seq Read Miss | The percent of the sequential read operations that were misses.
% Seq Write Hit | The percent of the sequential write operations that were immediately satisfied from cache.
% Seq Write Miss | The percent of the sequential write operations that were misses
% Seq Writes | Calculated value: 100*(seq writes per sec/total I/O operations per second).
% Sequential IO | Calculated value: 100 * (total seq I/Os per sec/total I/O operations per second)
% Write Hit | The percentage of write operations, performed by the volume, that were immediately satisfied by cache
% Write Miss | The percent of write miss operations performed each second by the volume. 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
Avg IO Size | Calculated value: (HA Kbytes transferred per sec/total IOs per sec)
Avg QOS Delay Per IO | Delay induced by service level management. Calculated value: (Delayed I/O Time /Delayed I/O Count /1000) (applies only to storage systems running PowerMaxOS 5878 or later)
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 (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 Pretetched Tracks/sec | The total prefetched tracks each second from the disk directors to the cache.
BE Read Reqs/sec | The number of read requests each second performed by the disk directors to the cache.
BE Reqs/sec | Number of read/write requests each second performed by the disk directors to cache.
BE Throughput Read | The number of MBs read by the disk directors from the disk each second
BE Throughput Transferred | Calculated value: (MBs read per sec + MBs written per sec)
BE Throughput Written | The number of MBs written to the disk from the disk director each second
BE Write Reqs/sec | The number of write requests each second performed by the disk directors to the cache.
Capacity of RDF Invalid Tracks | The capacity of SRDF invalid tracks
Device Block Size | The block size of the volume
Effective Used Capacity | The effective used capacity
External Read RT | The time that it takes to process a read outside of the system (V4)
External Response Time | The time that it takes to process an I/O request ioutside of the system (V4)
External Write RT | The time that it takes to process a write outside of the system (V4)
Host Hits/sec | The total number of host read I/O and write I/O operations performed each second by the volume that were immediately satisfied by cache.
Host IOs/sec | The total number of host read I/O and write I/O operations performed each second by the volume.
Host Misses/sec | The total number of host read I/O and write I/O operations missed each second by the volume.
Host Read Hits/sec | The total number of host read I/O operations performed each second by the volume that were immediately satisfied by cache.
Host Read Misses/sec | The total number of host read I/O operations missed each second by the volume.
Host Reads/sec | The total number of host read I/O operations performed each second by the volume.
Host Throughput | A cumulative number of host MBs read/writes per second
Host Throughput Read | A cumulative number of host MBs read per second
Host Throughput Written | A cumulative number of host MBs written per second
Host Write Hits/sec | The total number of host write I/O operations performed each second by the volume that were immediately satisfied by cache.
Host Write Misses/sec | The total number of host write I/O operations missed each second by the volume.
Host Writes/sec | The total number of host write I/O operations performed each second by the volume.
Internal Read RT | The internal read response time (V4)
Internal Response Time | The internal response time (V4)
Internal Write RT | The internal write response time (V4)
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 volume
Number of RDF Invalid Tracks | Number of SRDF invalid tracks (V3)
PowerPath Average Response Time | The average response time in milliseconds using PowerPath metrics
PowerPath Observed Delta RT | The difference between PowerPath average response time and device or storage group response time
PowerPath Read Response Time | The read response time from the perspective of PowerPath
PowerPath Write Response Time | The write response time from the perspective of PowerPath
Random Hits/sec | The total number of hits per second that were not sequential
Random IOs/sec | The number of I/Os from a host that is not identified as part of a sequential stream
Random Read Hits/sec | The number of random read I/Os that were satisfied from the cache.
Random Read Misses/sec | The number of random read I/Os that were misses.
Random Reads/sec | The number of read I/O commands from a host that is not identified as part of a sequential stream.
Random Write Hits/sec | The number of random write I/Os that were immediately placed in cache because space was available.
Random Write Misses/sec | The number of random write I/O operations per second that were misses.
Random Writes/sec | The number of write I/O commands from a host that is not identified as part of a sequential stream.
RDF Reads/sec | SRDF reads per second.
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 Throughput Read | SRDF MBs read per second.
RDF Throughput Written | SRDF MBs written per second
RDF Writes/sec | SRDF writes per second.
RDF/S Write RT | The average time that it took the volume to serve one write I/O
Read Miss RT | The average time a read miss operation was performed by the volume. A miss occurs when the requested data is not found in cache.
Read RT | The calculated average read response time
Response Time | The calculated average response time
Seq IOs/sec | The number of I/O operations performed each second that were sequential.
Seq Read Hits/sec | The number of sequential read operations performed each second by the volume that were immediately satisfied from cache
Seq Read Miss/sec | The number of sequential read operations performed each second by the volume that were misses
Seq Reads/sec | The number of read I/O operations performed each second that were sequential.
Seq Write Hits/sec | The number of sequential write operations performed each second by the volume that were immediately satisfied from cache
Seq Write Misses/sec | The number of sequential write operations performed each second by the volume that were misses
Seq Writes/sec | The number of write I/O operations performed each second that were sequential.
Slot Collisions/sec | Write misses/sec due to the desired cache slot being locked by another request (Task 7 + Task 11) (V4)
Slot Collisions RT | The average response time of a write miss due to the desired cache slot being locked by another request (Task 7 + Task 11) (V4)
Total Capacity | The total capacity of the thin volume (GB)
Total Response Time | The total response time
VAAI Total Command Count | Number of VAAI commands that were issued
VAAI Total Time | VAAI total time
VAAI Unmap Command Count | Number of VAAI unmap commands that were issued.
VAAI Unmap MB | VAAI Unmap MB (V3)
VAAI Unmap Throughput | VAAI Unmap throughput
VAAI Write Same Command Count | Number of VAAI write same commands issued.
VAAI Write Same MB | VAAI Write Same MB (V3)
VAAI Write Same Throughput | VAAI Write Same throughput
VAAI XCopy Command Count | Number of VAAI XCopy commands issued
VAAI XCopy MB | VAAI XCopy MB (V3)
VAAI XCopy Throughput | VAAI XCopy throughput
WP Count | The number of tracks in write pending mode for the volume.
WP Used Capacity | WP used capacity
Write Miss RT | The average time a write miss operation was performed by the volume. A miss occurs when the write operation has to wait while data is destaged from cache to disks.
Write Paced Delay (ms) | Write paced delay (V3).
Write RT | The calculated average write response time

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