Storage system response characteristics to failure conditions

True Copy for Mainframe User Guide for VSP One Block 85

Version

10.5.x

File Size

2745 KB

Audience

anonymous

Part Number

MK-26VSP1B036-02

ft:lastEdition

2026-06-23

VSP One Block 85 supports CGROUP in the GDPS environment by performing PPRC-compatible actions and returning PPRC-compatible messages according to failure conditions.

To enable PPRC support, run the CCI raidcom modify remote_replica_opt command with "enable" set to the -pprc_opt option. If the -pprc_opt disable option is specified, the host processor generates a system console message that includes the SIM instead of the IEA494I or IEA491E message.

The following figure shows failure conditions, with corresponding storage system response characteristics in the table following the figure.

Failure condition		Pairs split?	Expected messages	FREEZE function
1. Failure of all channel interfaces on the primary system		No	No IEA480E, IEA491E, or IEA494I messages display.	Not activated¹
2. Failure of a disk on the primary system	Failure of one physical disk in a parity group	No	(1) IEA480E message (SIM for blocked physical disk or disk's port) is displayed when the next I/O is issued to any volume in the parity group. (2) No IEA491E or IEA494I messages display.	Not activated¹
2. Failure of a disk on the primary system	Failure of two physical disks in a parity group	No	(1) IEA480E message (SIM for blocked LDEV) is displayed when the next I/O is issued to any volume in the parity group. (2) No IEA491E or IEA494I messages display.	Not activated²
3. Failure of a link between the primary and secondary system		No	(1) IEA480E message (SIM for blocked TCz path) is reported when the next I/O to any device in this primary system is issued. (2) No IEA491E or IEA494I messages display.	Not activated
4. Failure of NVS on the primary system, failure of primary system read cache	One side of primary system cache blocked due to failure	No³	(1) IEA480E (SIM for cache blocked) is reported when the next I/O to any device in this primary system is issued. (2) No IEA491E or IEA494I messages display.	Not activated
	One side of primary system cache blocked due to maintenance	No³	No IEA480E, IEA491E, or IEA494I messages display.	Not activated
	One side of primary system cache blocked by SET CACHE OFF	No³	No IEA480E, IEA491E, or IEA494I messages display.	Not activated
5. Both sides of primary system cache blocked due to failure		No	No IEA480E, IEA491E, or IEA494I messages display. The primary system returns CC=3 for all I/Os.	Not activated
6. Failure of a disk on the secondary system	Failure of a disk in a parity group	No	(1) The secondary system reports IEA480E message (SIM for blocked disk or disk's port) to either the primary system or the host processor (whichever issues the next I/O first) when the next I/O is issued to any volume in the parity group. If primary system receives the SIM, it passes the SIM to the attached host processor, and the IEA480E message is reported when the next I/O to this primary system is issued to any P-VOL paired with the volume in the parity group. (2) No IEA491E or IEA494I messages display.	Not activated
6. Failure of a disk on the secondary system	Failure of two disks in a parity group	Yes	(1) The secondary system reports IEA480E message (SIM for LDEV blocked) to either the primary system or the host processor (whichever issues the next I/O first) when the next I/O is issued to any volume in the parity group. If primary system receives the SIM, it passes the SIM to the attached host processor, and the IEA480E message is reported when the next I/O to this primary system is issued to any P-VOL paired with the volume in the parity group. (2) One or more IEA494I message showing EXTENDED LONG BUSY display. (3) One or more IEA491E or IEA494I message showing PAIR SUSPENDED display.	Activated if the FREEZE option is enabled for the affected primary system pairs.
7. Failure of NVS on the secondary system, failure of secondary system read cache	One side of secondary system cache blocked due to failure	No	(1) The secondary system reports IEA480 message (SIM for cache blocked) to either the primary system or the host processor (whichever issues the next I/O first). If primary system receives the SIM, it passes the SIM to the attached host processor. Therefore, IEA480 is reported when the next I/O to any device in this primary system issued. (2) No IEA491E or IEA494I messages display.	Not activated
	One side of secondary system cache blocked due to maintenance	No	No IEA480, IEA491E, or IEA494I messages display.	Not activated
	One side of secondary system cache blocked by SET CACHE OFF	No	No IEA480, IEA491E, or IEA494I messages display.	Not activated
8. Both sides of secondary system cache blocked due to failure		Yes	(1) No IEA480 (SIM for blocked cache) is displayed. (2) One or more IEA494I message showing EXTENDED LONG BUSY display. (3) One (or more) IEA491E and IEA494I messages showing PAIR SUSPENDED display. (4) If CGROUP FREEZE and RUN are issued, IEA494I messages showing PAIR SUSPENDED display when the primary system accepts CGROUP RUN. These messages are from the TCz pairs for which FREEZE option is enabled, and from main volumes that did not already report IEA491E/IEA494I at (3).	Activated if the FREEZE option is enabled for the affected primary system pairs.
9. Failure of all links between the primary and secondary system		Yes	(1) IEA480 (SIM for TCz path blocked) message is reported when the next I/O to any device in this primary system is issued. (2) One or more IEA494I message showing EXTENDED LONG BUSY display. (3) One or more IEA491E or IEA494I message showing PAIR SUSPENDED display.	Activated if the FREEZE option is enabled for the affected primary system pairs.
10. Power failure	a. On the primary system	No	No IEA480, IEA491E, or IEA494I messages display.	Not activated
10. Power failure	b. On the secondary system	Yes	(1) IEA480 (SIM for blocked TCz path) message is reported when the next I/O to any device in this primary system is issued. (2) One or more IEA494I message showing EXTENDED LONG BUSY display. (3) One or more IEA491E or IEA494I message showing PAIR SUSPENDED display.	Activated if the FREEZE option is enabled for the affected primary system pairs.
Notes: Because of the nature of the failure, there is no means of activating the FREEZE feature. FREEZE is not activated, though activation is possible with the relevant command. When one side of the primary system cache is blocked, TCz pairs in Duplex status are not affected, but Pending pairs are split. Splitting pairs in Pending status provides additional protection against unexpected events caused by cache failure.