Using the four-system complex shown earlier in Figure 1, assume that it is necessary to purge SYS1 from the ring. SYS1 is a quiesced system. The operator on SYS2 issues the purge command; thus, SYS2 is the assisting system. The required steps are:

1. On SYS2, the operator issues VARY GRS(SYS1), PURGE. The following messages appear:

   ISG016I SYSTEM SYS1 OWNS OR IS WAITING FOR GLOBAL RESOURCES
   ISG017D CONFIRM PURGE REQUEST FOR SYSTEM SYS1 - REPLY NO OR YES

   These messages indicate that users on SYS1 still own, or are waiting for, global resources. The operator on SYS2 should reply NO unless the operator knows the work on SYS1 has been shut down. The operator on SYS1 must shut the work down. Replying YES to message ISG017D might create a data integrity exposure. When the work on SYS1 has been shut down, the operator on SYS2 can reissue the VARY GRS(SYS1), PURGE command.

2. On SYS2, the following message appears:

   ISG011I SYSTEM SYS1 - BEING PURGED FROM GRS COMPLEX

3. On all active systems, the following message appears:

   ISG013I SYSTEM SYS1 - PURGED FROM GRS COMPLEX

4. On SYS1, the operator must stop the system. At this point, SYS1 is no longer known to global resource serialization. The ring consists of SYS2, SYS3, and SYS4. To rejoin the ring, SYS1 must reIPL with GRS=JOIN.
   While purging SYS1, global resource serialization detected a potential data integrity exposure, indicated by message ISG016I. When this message appears, the operator should follow the installation's procedures for resolving the problem, such as contacting the system programmer responsible for investigating the state of resources. More information about the problem normally appears in SYSLOG, where the following message appears to describe any resources that might have been damaged by purging the system:

   ISG018I REQUESTORS FROM SYSTEM SYS1 HAVE BEEN PURGED FROM RESOURCES
             NAMED xxxx,yyyy