HP 3000 Manuals HP 3000 Manuals
System Backup Changes for MPE/iX
by Jeff Vance
Commercial Systems Division
_____________________________________________________________________
| |
| The most important concept for System Managers to know is that|
| STORE @.@.@ may no longer backup all files on their systems! |
| In fact, all backup jobs, UDCs, scripts, programs, and so on, |
| need to be changed to use the HFS (Hierarchical File System) |
| syntax. These changes should be done even if the system does |
| not currently contain HFS directories or file name. |
_____________________________________________________________________
BACKGROUND
This version of MPE/iX has been enhanced to support POSIX interfaces.
Even though POSIX functionality has been tightly integrated into the
operating system, we have been especially sensitive to backwards
compatibility issues. In general, a POSIX-unaware user need not be
concerned with the Hierarchical File System (HFS), directories, longer
file names, lower case file names, and so on. System Administrators, on
the other hand, must understand these new features in order to
effectively and safely manage their HP 3000 systems.
The MPE/iX file system and Command Interpreter (CI) support two syntaxes:
the familiar MPE syntax (8 character file names, starting with a letter,
case insensitive, and so on), and the new HFS syntax. The HFS syntax
exposes the hierarchical directory, case sensitive file names, long file
names, special characters in file names (such as underscore), and so on.
By default, all names supplied to file system intrinsics and to the CI
are considered to be MPE names. Therefore, a :LISTFILE m@ only selects
MPE named files. This example of the LISTFILE command would not find the
file named my_file.old, since this is not a legal MPE name. To select
HFS named objects (files and/or directories), the HFS syntax must be
used.
If the file name begins with a "." (period) or a "/" (slash) it is
considered an HFS name. This is unambiguous since legal MPE names cannot
start with either of these characters, and these characters are not valid
file name terminators. To select the file named my_file.old the LISTFILE
command needs to be specified as LISTFILE ./m@.
To select all objects under a directory the HFS name must be ended using
the slash character (or the ;TREE option can be specified). For example:
LISTFILE ./mydir/ lists mydir and all files and directories at all levels
under mydir.
In both of the previous HFS examples, the object pathname begins with
"./", which reads as "starting in my Current Working Directory (CWD)".
(The CWD is similar to the logon group.) HFS pathnames can also begin at
root. Root (syntactically expressed as "/") is the beginning of the
entire directory structure. All MPE accounts are directly under the root
directory. To display the SYS account and all groups and files
underneath SYS, use LISTFILE /SYS/. Note that "SYS" must appear in upper
case and the trailing slash causes all objects under SYS to be selected.
Likewise, LISTFILE /SYS/PUB/ selects the PUB group under the SYS account
and all objects under PUB.
STORE @.@.@
Before the POSIX release of MPE/iX, STORE @.@.@ implied that all files on
the system would be selected for backup. Since the file name ("@.@.@")
does not begin with a "." or a "/" it is assumed to be an MPE name. Thus
only MPE legal file names directly under MPE groups will be stored. If
there are HFS named objects in the directory they will not be backed up.
The only way to back up the entire system is STORE /. STORE / starts at
root and stores all objects at all levels under root, including root
itself.
The STORE program has been enhanced to detect cases where a full system
backup was intended but it may not occur due to the MPE syntax used in
the STORE command. If the fileset name is "@.@.@" or "@.@.ACCOUNT",
STORE will display a console message, set the STOREJCW and cause a
repeated console reply message. This reply message does not interfere
with the STORE operation, it simply requires the operator to acknowledge
that potentially all files on the system were not backed up. If the
fileset name is "@.GROUP" then only the STOREJCW is set, since this is
not likely a system backup usage of STORE, and therefore the operator
does not need to be involved.
In all cases where the first component of the fileset name is "@", STORE
will "soft fail". This means that the STOREJCW is non-zero, and a CIERR
is reported, but all MPE nameable files matching the fileset will be
selected for backup.
If the fileset name is in HFS syntax, or if the new NOHFSWARN option is
specified, the above behavior is suppressed. STORE used with ;transport
option, RESTORE and VSTORE have not been changed to detect these
conditions. For more information consult online HELP on the STORE
command.
SUMMARY
All system backup related STORE commands in jobs, UDCs, programs, and so
on, should be changed to use the new HFS syntax. The table below shows
how to convert MPE fileset names to HFS names.
MPE STORE fileset HFS STORE fileset
----------------- -----------------
@.@.@ ==> /
@.@[.account] ==> /ACCOUNT/
@[.group[.account]] ==> /ACCOUNT/GROUP/
@.@.prod@,@.@.@mfg ==> /PROD@/, /@MFG/
@.@.sys,@.@.@-@.@.sys ==> /SYS/, / - /SYS/