XRC information in SMF type 42 records

The system data mover (SDM) writes a System Management Facilities (SMF) record type 42 subtype 11 for extended remote copy session statistics whenever the SMF timer interval ends. This SMF XRC information can be used by the DFSMSdfp Optimizer to provide information for capacity planning and environmental tuning.

Note: XRC cannot process SMF records for physical sessions that have ended during the SMF interval. A session can be ended, for instance, due to a “lost” physical session.

The following three fields are included in the SMF type 42 record when a subtype 11 record is written:

Offsets Dec. Hex	Name	Length	Format	Description
36 24	SMF42XRO	4	binary	Offset to XRC statistics.
40 28	SMF42XRL	2	binary	Length of XRC statistics.
42 2A	SMF42XRN	2	binary	Number of XRC sessions.

Table 1 contains the SMF record type 42 information that applies to XRC. This information is grouped within a subtype 11 record, which is only included when there is an active XRC session. A volume must be in duplex state before SMF information is accumulated for that volume.

Table 1. Record layouts for subtype 11
Offsets Dec. Hex	Name	Length	Format	Description
The following relate to an XRC session:
0 0	S42XRID	8	EBCDIC	Logical session ID.
8 8	S42XRTYP	8	EBCDIC	Session type: `XRC` = disaster recovery session, `MIGRATE` = migration session.
16 10	S42XRSSO	4	binary	Offset to first storage subsystem identifier (SSID) data section.
20 14	S42XRSSN	2	binary	Number of SSIDs for the session.
22 16	S42XRSSL	2	binary	Length of SSID data section.
24 18	S42XRVLO	4	binary	Offset to first volume data section.
28 1C	S42XRVLN	2	binary	Number of volume data sections.
30 1E	S42XRVLL	2	binary	Length of volume data sections.
The following relate to XRC SSID data:
0 0	S42XRSNX	4	binary	Offset to next SSID data section (0 if last SSID).
4 4	S42XRSID	2	binary	SSID.
6 6	S42XRIDP	1	binary	Storage control session ID.
7 7		1		Reserved.
8 8	S42XRVSH	4	binary	Number of primary volumes associated with this SSID that are still included in the XRC session at the end of the SMF interval. This includes both volume pairs and utility volumes.
12 C	S42XRTPR	4	binary	Total number of primary SDM record updates read.
16 10	S42XRNWD	4	binary	Number of primary SDM reads with data.
20 14	S42XRNND	4	binary	Number of primary SDM reads with no data.
24 18	S42XRNLR	4	binary	Number of primary SDM record updates left to be read at the point in the SMF when information is collected.
28 1C	S42XRNFW	4	binary	Number of format writes.
32 20	S42XRNUW	4	binary	Number of update writes.
36 24	S42XRARS	4	binary	Average record update size of data processed, in bytes.
40 28		4		Reserved.
The following relate to XRC volumes:
0 0	S42XRVLX	4	binary	Offset to next volume data section (0 if last volume).
4 4	S42XRVLV	6	EBCDIC	Volume serial number.
10 A	S42XRVAV	6	EBCDIC	Other volume serial number in pair.
16 10	S42XRVPS	1	EBCDIC	"P" if primary volume, "S" if secondary volume, "U" if utility volume.
17 11		1		Reserved.
18 12	S42XRVSS	2	binary	SSID associated with volume.
20 14	S42XRVPR	4	binary	Primary = total number of primary SDM record updates read. Secondary = total number of SDM records written.
24 18	S42XRVWD	4	binary	Primary = number of SDM reads with data. Secondary = 0.
28 1C	S42XRVND	4	binary	Primary = number of SDM reads with no data. Secondary = 0.
32 20	S42XRVFW	4	binary	Number of format writes.
36 24	S42XRVUW	4	binary	Number of update writes.
40 28	S42XRVRS	4	binary	Primary = average record size read, in bytes. Secondary = average record size written, in bytes.
44 2C	S42XRVRW	4	binary	Primary = number of read tracks. Secondary = number of write tracks.
48 30		4		Reserved.