Server I/Os added to Performance Monitor

Ops Center High Availability User Guide

Version: 10.8.x
File Size: 3.9 MB
Audience: anonymous
Part Number: MK-99ADM003-10

The number of I/Os (reads and writes) to GAD volumes that is added to Performance Monitor depends on the GAD status, as shown the following tables.

Table. Writes to GAD volumes to be added to Performance Monitor
GAD status	P-VOL	S-VOL
Mirrored	The sum of the following values: Number of writes to the P-VOL Number of RIOs to the P-VOL from the S-VOL	The sum of the following values: Number of reads from the S-VOL Number of RIOs to the S-VOL from the P-VOL
Quorum disk blocked or no quorum disk volume	Number of writes to the P-VOL	The sum of the following values: Number of writes from the server to the S-VOL Number of RIOs from the P-VOL to the S-VOL
Mirroring	Number of writes to the P-VOL	Number of RIOs to the S-VOL from the P-VOL
Suspended (when the P-VOL has the latest information)	Number of writes to the P-VOL	Not counted*
Suspended (when the S-VOL has the latest information)	Not counted*	Number of writes to the S-VOL
Blocked	Not counted*	Not counted*
* Reads and writes by a server are illegal requests and cause an error. However, they could be counted as I/O.

Table. Reads to GAD volumes to be added to Performance Monitor
GAD status	P-VOL	S-VOL
Mirrored	Number of reads from the P-VOL	Number of reads from the S-VOL
Quorum disk blocked or no quorum disk volume	Number of reads from the P-VOL	Number of reads from the S-VOL
Mirroring	Number of reads from the P-VOL	Not counted*
Suspended (when the P-VOL has the latest information)	Number of reads from the P-VOL	Not counted*
Suspended (when the S-VOL has the latest information)	Not counted*	Number of reads from the S-VOL
Blocked	Not counted*	Not counted*
* Reads and writes from a server are illegal requests and cause an error. However, they could be counted as I/O.

Table. Relation between the number of I/Os added to Performance Monitor and the number of server I/Os
GAD status	Number of writes	Number of reads
Mirrored	Approximately the same* as the number of writes to the P-VOL or S-VOL	The same as the total number of reads from the P-VOL and S-VOL
Quorum disk blocked	The same as the number of writes to the P-VOL	The same as the number of reads from the P-VOL
Quorum disk blocked or no quorum disk volume	The same as the number of writes to the P-VOL	The same as the total number of reads from the P-VOL and S-VOL
Mirroring	The same as the number of writes to the P-VOL	The same as the number of reads from the P-VOL
Suspended (P-VOL has latest data)	The same as the number of writes to the P-VOL	The same as the number of reads from the P-VOL
Suspended (S-VOL has latest data)	The same as the number of writes to the S-VOL	The same as the number of reads from the S-VOL
Blocked	Not counted	Not counted
* For writes by a server, RIOs might be divided before being issued. For this reason, this number might differ from the number of writes by a server.