Pubsets (public volume sets, PVS) are sets of shared volumes and are used in BS2000 together with private volumes and Net-Storage for storing files (see also the “Introduction to System Administration” [4]).
Pubset is the general name for a set of disks irrespective of the pubset type (SF or SM pubset).
A pubset is identified by a unique pubset identifier (or pubset ID). A pubset is addressed by the user for the purposes of file access using its (syntactically identical) catalog ID (or catid).
The DMS function Multiple Public Volume Sets (MPVS) supports the use of several independent pubsets in a single BS2000 system. Management information on the various pubsets of a system is stored in the MRS catalog MRSCAT.
There is a “preferred” pubset (home pubset) which is required for loading, operating and shutting down the system and which must be available throughout the entire session.
In addition to this home pubset, it is possible to import other pubsets. The disks of an imported pubset are regarded as a single unit by the system and managed as such. By calling on the logical DMS functions, users can create, process and delete files and job variables on an imported pubset, provided they are authorized to do so.
Home pubset
This pubset contains the files required for startup (and automatic restart) (see the “Introduction to System Administration” [4]).
A home pubset is imported automatically during BS2000 system initialization.
Standby pubset
This pubset (catid STBY) is pregenerated in all SE servers and located on an internal disk (D0) which is working even without active SAN connection to other disks. It contains a preinstalled emergency system which may be used for installing or repairing the home pubset. However, the emergency system is not suitable for productive use.
Reserve pubset
This pubset, which contains the same files as the home pubset, can carry out the functions performed by the home pubset when the home pubset fails, i.e. the BS2000 operating system can be loaded and operated from this standby pubset.
In contrast to the standby pubset a reserve pubset allows not only installing or repairing the home pubset, it also allows immediate continuation of productive use during ongoing recovery of the home pubset.
Shared pubset (SPVS)
If the software product HIPLEX MSCF and a suitable hardware configuration are used, simultaneous access to a shared pubset is possible from more than one system.
Up to 16 systems linked in a shared HIPLEX MSCF network can access this shareable pubset as “sharers” via a direct hardware path. One of the participants in the network is designated the temporary owner of this pubset and handles the functions for file, user and access management for the other sharers. All management requests from subordinate participants (“pubset slaves” or “slave sharers”) must be forwarded to the owner (“pubset master”) via HIPLEX MSCF.
If the pubset master crashes, a pubset-specific job variable (see the “Job Variables” manual [9]) is set on all pubset slaves. In this case, one of the current pubset slaves can take over the role of the pubset master without having to export the pubset because of this. If this so-called master switch is not configured or fails, systems support must either export the pubset to all the remaining pubset slaves or (after the problem has been corrected) declare one of the remaining pubset slaves to be the new pubset master by means of /IMPORT-PUBSET ...,SHARER-TYPE=*MASTER(MASTER-CHANGE=*YES).
The whole concept of shared pubsets (hardware configuration, pubset management, data access) is described in detail in the “HIPLEX MSCF” manual [7].
Paging pubset
During the session the paging area can be dynamically extended (/EXTEND-PAGING-AREA). It is essential here that the associated pubset is imported and the maximum size of the paging area (4 TByte) is observed.
Pubset organization
In order to use pubsets efficiently, the following disk organization is recommended:
A pubset must be ready to be used as the home pubset. In other words all the users authorized to access the system must be entered in the user catalog for this pubset (LOGON validation via the home pubset). This pubset generally corresponds to the one created as a result of system installation.
It is possible to install a second pubset as a reserve, so that the session can be continued on this reserve pubset should the home pubset crash.
All the user files should be distributed over further pubsets. In this context, one of these pubsets is assigned to each user as the user default pubset.
The paging files should be distributed over several pubsets, but should not be located on pubres, the first disk of a pubset.
A paging area of at least 200 Mbytes should be set up in the home pubset.
Recommended disk organization
One disk (PUBA00) forms the home pubset.
One disk (PUBB00) forms the reserve pubset.
In all configurations it is important to ensure that the home pubset and the reserve pubset do not reside on the same disk storage unit.
Three further user pubsets (here: SF pubsets J, K and L) are set up in addition on the disks PUBJ00 and PUBJ01, PUBK00 and PUBK01, PUBL00 and PUBL01.
Further pubsets can be set up; these have to be imported when required.
Up to “system ready”, at least one paging file is needed in the home pubset. Paging files on the pubsets J, K and L either can be specified in the BS2000 parameter file for startup, or
can be added from “system ready”, e.g. via the CMDFILE.The home pubset is always the default pubset of the TSOS user ID. All standard files that are required for fast startup and automatic restart, for example, are to be stored on this pubset.
The home pubset should not be assigned to any user as the default pubset, but should only contain the files of all system identifiers.Since the reserve pubset is to assume the home pubset function, it must contain the same files as the home pubset.
The reserve pubset should therefore not be assigned to any users as the default pubset and should, if possible, be used only by the operating system (reduced update requirements).Since there is not just a single catalog, but one catalog for each pubset, the size of each catalog must be seen in relation to the size of the pubset or the file volume. The catalog size is influenced by:
the number of files that reside on the pubset
the number of private files cataloged in the pubset
the number of job variables that reside on this pubset.
TSOSCAT, MRSCAT and SYSSRPM are created during installation or
/IMPORT-PUBSET ACTUAL-JOIN=*FIRST,...,without the user having any say in the matter (exception: TSOSCAT size).
The files on the pubsets may be distributed as follows:
Pubsets | Disks | Files |
|---|---|---|
Home pubset | PUBA00 | TSOSCAT |
reserve pubset | PUBB00 | TSOSCAT |
User pubset | PUBJ00 |
|
PUBJ01 |
| |
| PUBK00 |
| |
| PUBK01 |
| |
| PUBL00 |
| |
PUBL01 |
| |
in addition:
|
Structure of /ADD-USER for the user ID COMPILER and four users:
Entries for the home pubset A:
/ADD-USER USER-ID=COMPILER,...,PUBSET=A,DEFAULT-PUBSET=A, ... / ...,PUBLIC-SPACE-LIMIT=n /ADD-USER USER-ID=USER1,...,PUBSET=A,DEFAULT-PUBSET=J, ... / ...,PUBLIC-SPACE-LIMIT=0 /ADD-USER USER-ID=USER2,...,PUBSET=A,DEFAULT-PUBSET=K, ... / ...,PUBLIC-SPACE-LIMIT=0 /ADD-USER USER-ID=USER3,...,PUBSET=A,DEFAULT-PUBSET=K, ... / ...,PUBLIC-SPACE-LIMIT=0 /ADD-USER USER-ID=USER4,...,PUBSET=A,DEFAULT-PUBSET=L, ... / ...,PUBLIC-SPACE-LIMIT=0
Entries for the reserve pubset B:
/ADD-USER USER-ID=COMPILER,...,PUBSET=B,DEFAULT-PUBSET=B, ... / ...,PUBLIC-SPACE-LIMIT=n /ADD-USER USER-ID=USER1,...,PUBSET=B,DEFAULT-PUBSET=J, ... / ...,PUBLIC-SPACE-LIMIT=0 /ADD-USER USER-ID=USER2,...,PUBSET=B,DEFAULT-PUBSET=K, ... / ...,PUBLIC-SPACE-LIMIT=0 /ADD-USER USER-ID=USER3,...,PUBSET=B,DEFAULT-PUBSET=K, ... / ...,PUBLIC-SPACE-LIMIT=0 /ADD-USER USER-ID=USER4,...,PUBSET=B,DEFAULT-PUBSET=L, ... / ...,PUBLIC-SPACE-LIMIT=0
Entries in the user catalog are in “back-to-front” order to the home pubset. As a result of this, it is not necessary to make any modifications when pubset B is used for loading.
Entries for user pubset J:
/ADD-USER USER-ID=USER1,...,PUBSET=J,...,PUBLIC-SPACE-LIMIT=n/ADD-USER USER-ID=USER4,...,PUBSET=J,...,PUBLIC-SPACE-LIMIT=0If the system parameter FSHARING=0 (default setting), entering USER4 with space limit 0 is necessary on pubset J in order to grant this user access to shareable files of other users located on this pubset ( USER2 and USER3 cannot do this). If FSHARING=1 is set in the BS2000 parameter file, all users are granted access (and no catalog entry for USER4 with space limit 0 is required).
Entries for user pubset K:
/ADD-USER USER-ID=USER2,...,PUBSET=K,...,PUBLIC-SPACE-LIMIT=n/ADD-USER USER-ID=USER3,...,PUBSET=K,...,PUBLIC-SPACE-LIMIT=nEntries for user pubset L:
/ADD-USER USER-ID=USER4,...,PUBSET=L,...,PUBLIC-SPACE-LIMIT=n
The system finds the default allocations of the individual users by the entries in the current home pubset. When a file is addressed via ‘$userid.’, the file is sought in the pubset that is the default pubset for ‘userid’.
/ADD-USER is described in the “Commands” manual [2].
Notes on organizational division:
Paging files outside the home pubset for startup are specified in the BS2000 parameter file.
When the system is in operation, the paging area can be extended with
/EXTEND-PAGING-AREA.The entries in the user catalog should be up-to-date and should be saved regularly (see the “Introduction to System Administration” [4]).
The startup parameter service can be called with the help of the dialog startup in order to change the default values (see the “Introduction to System Administration” [4]).
Advantages of this disk organization
Reliability
Failure of the IPL on PUBA00:
By virtue of a double IPL (IPL also on PUBB00) or a triple IPL (IPL also on PUBB00 and PUBL01), the system can be loaded at any time.Failure of the user/file catalog or the entire pubset A:
By distributing the entries in the user catalog judiciously (“back to front”) over PUBB00 and selectively updating the files and catalog entries maintained there, the system can be loaded via PUBB00 at any time without impairing operation for the user.Failure of pubset L (without paging):
The system can continue to be used. Only USER4 will be affected in his work.Failure of pubset B (reserve pubset):
The system can continue to be used as usual. The reserve pubset can be reconstructed online.
Version changeover
A system of the new version can be created on pubset B under the BS2000 operating system from pubset A. Pubset X can then be appended to the current system by means of
/IMPORT-PUBSET ACTUAL-JOIN=*FIRST. After all required files or procedures have been readied (online), a startup of the new version can be effected. If the changeover is not successful, the loadable pubset A ready for operation is available as a fallback solution, i.e. the downtime of the system is reduced to a minimum.
ACTUAL-JOIN=*FIRST, e.g. in order to create paging files or to copy files onto it. In this case /IMPORT-PUBSET ACTUAL-JOIN=*FIRST is already performed under SIR.