Determining the file system owner

To determine the zFS owner of a zFS file system, use the zfsadm lsaggr command. To determine the z/OS® UNIX owner, use the following commands:

df -v shell command
d omvs,f operator command
f bpxoinit,filesys=d,all operator command

Figure 1 shows the output of the zfsadm lsaggr command and the df -v command after the file system was mounted (as shown in Figure 1) issued from SY2:

Figure 1. zfsadm lsaggr and df -v output after mount

# zfsadm lsaggr
IOEZ00106I A total of 1 aggregates are attached
PLEX.JMS.AGGR008.LARGE08                        SY2       R/W

# df -v
Mounted on     Filesystem                Avail/Total    Files      Status    
/zfsmnt5       (PLEX.JMS.AGGR008.LARGE08) 2853944/3745440 4294917290 Available
ZFS, Read/Write, Device:26, ACLS=Y
File System Owner : SY2         Automove=Y      Client=N
Filetag : T=off   codeset=0
Aggregate Name : PLEX.JMS.AGGR008.LARGE08

Figure 2 shows the output of the d omvs,f command after the file system was mounted.

Figure 2. d omvs,f output after mount

D OMVS,F                                                              
BPXO045I 14.38.11 DISPLAY OMVS                                    
OMVS     000E ACTIVE             OMVS=(P0,VM)                         
TYPENAME   DEVICE ----------STATUS----------- MODE  MOUNTED    LATCHES
ZFS            26 ACTIVE                      RDWR  02/02/2011  L=55  
  NAME=PLEX.JMS.AGGR008.LARGE08                     14.37.44    Q=0   
  PATH=/zfsmnt5                                                      
  OWNER=SY2      AUTOMOVE=Y CLIENT=N

Figure 3 shows the output of the zfsadm lsaggr command and the df -v command after the file system was moved (as shown in Figure 1 ) by both z/OS UNIX and zFS and SY2 has come back up. The zfsadm lsaggr and df -v commands are issued from SY2:

Figure 3. zfsadm lsaggr and df -v output after movement

# zfsadm lsaggr
IOEZ00106I A total of 1 aggregates are attached
PLEX.JMS.AGGR008.LARGE08                        SY3       R/W

# df -v
Mounted on     Filesystem                Avail/Total    Files      Status    
/zfsmnt5       (PLEX.JMS.AGGR008.LARGE08) 2853944/3745440 4294917290 Available
ZFS, Read/Write, Device:26, ACLS=Y
File System Owner : SY1         Automove=Y      Client=N
Filetag : T=off   codeset=0
Aggregate Name : PLEX.JMS.AGGR008.LARGE08

Figure 4 shows the output of the d omvs,f operator command after the file system was moved. Notice two important points:

The zFS owner (SY3) and the z/OS UNIX owner (SY1) are different.
The last df -v command reports that SY2 is not a client, even though SY2 is not the z/OS UNIX owner.

Figure 4. d omvs,f output after movement

D OMVS,F                                                              
BPXO045I 14.38.11 DISPLAY OMVS                                    
OMVS     000E ACTIVE             OMVS=(P0,VM)                         
TYPENAME   DEVICE ----------STATUS----------- MODE  MOUNTED    LATCHES
ZFS            26 ACTIVE                      RDWR  02/02/2011  L=55  
  NAME=PLEX.JMS.AGGR008.LARGE08                     14.37.44    Q=0   
  PATH=/zfsmnt5                                                      
  OWNER=SY1      AUTOMOVE=Y CLIENT=N

This situation occurs because the zFS file system is sysplex-aware and file requests are not function shipped by z/OS UNIX. Rather, the file requests are handled by zFS and metadata updates are sent to the zFS owner. Each local catch-up mount causes zFS to open the file system data set for read/write, and each system is prepared to read and write the file system. Because the file system is opened on each system, each system prepares to take ownership of the file system if that becomes necessary.

Tip: You can use the DISPLAY GRS system command to determine the zFS owner of a zFS file system. Use the RNAME for either the read-only or read/write file system. For example, issue the following command to display the system name of the zFS owner as the exclusive owner of the resource name.

D GRS,RES=(SYSZIOEZ,IOEZLT.file_system_name)

For more information, see the serialization summary and list of ENQs in z/OS MVS Diagnosis: Reference.