IBM Support

SI34983 - OSP-PERFM Temporary file system

PTF Cover Letter


PTF ( Program Temporary Fixes ) Cover letter


Order this fix

Abstract

OSP-PERFM Temporary file system


Pre/Co-Requisite PTF / Fix List

REQ  LICENSED      PTF/FIX  LEVEL

TYPE PROGRAM  REL  NUMBER   MIN/MAX  OPTION
---- -------- ---  -------  -------  ------
PRE  5761SS1  610  SI34970   00/00    0000
PRE  5761SS1  610  SI34971   00/00    0000
PRE  5761SS1  610  SI34917   00/00    0000
PRE  5761SS1  610  SI35036   00/00    0000
PRE  5761SS1  610  SI34972   00/00    0000
PRE  5761SS1  610  SI34968   00/00    0000
DIST 5761999  610  MF46527   00/00    0000



NOTICE:
-------
Application of this PTF may disable or render ineffective programs that
use system memory addresses not generated by the IBM translator,
including programs that circumvent control technology designed to limit
interactive capacity to purchased levels.  This PTF may be a prerequisite
for future PTFs.  By applying this PTF you authorize and agree to the
foregoing.

This PTF is subject to the terms of the license agreement which
accompanied, or was contained in, the Program for which you are obtaining
the PTF.  You are not authorized to install or use the PTF except as part
of a Program for which you have a valid Proof of Entitlement.

SUBJECT TO ANY WARRANTIES WHICH CAN NOT BE EXCLUDED OR EXCEPT AS EXPLICITLY
AGREED TO IN THE APPLICABLE LICENSE AGREEMENT OR AN APPLICABLE SUPPORT
AGREEMENT, IBM MAKES NO WARRANTIES OR CONDITIONS EITHER EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OR CONDITIONS OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON INFRINGEMENT,
REGARDING THE PTF.

The applicable license agreement may have been provided to you in printed
form and/or may be viewed using the Work with Software Agreements (WRKSFWAGR)
CL command.





APAR Error Description / Circumvention

-----------------------------------------------
Many applications make use of temporary working files and
directories. These file system objects do not require being
forced to permanent storage to ensure their integrity after a
system crash. However, access to the objects must be controlled
through owner, group, and public authorities. A new type of file
system containing owned temporary objects should be created that
will provide better performance than with permanent objects.

CORRECTION FOR APAR SE37352 :
-----------------------------
The PTF will enable users to create and mount temporary
user-defined file systems. See the special instructions for more
details.

CIRCUMVENTION FOR APAR SE37352 :
--------------------------------
None.


Activation Instructions


This PTF contains objects that are activated only at IPL time.
Therefore, if this PTF is applied as an immediate PTF, you must
perform an IPL of the system to activate the PTF. Applying the
PTF as an immediate PTF will ensure that the PTF becomes active
even after an abnormal IPL where delayed PTFs are not applied.

If the PTF is applied as a delayed PTF, no further action is
necessary.





Special Instructions


The integrated file system must perform a large number of disk
operations to ensure the integrity of file system objects after
a system crash. These disk operations needlessly slow down
applications that create and delete objects that do not need to
persist across IPLs. This PTF provides function that enables the
user to create and mount a special type of user-defined file
system (UDFS) that contains only temporary objects. Temporary
objects do not require extra disk operations because they are
automatically deleted by the system when the system is
restarted or when the file system is unmounted. Applications may
be able to increase their performance through the use of a
temporary file system. One possible use of this support would be
to mount a temporary file system over the '/tmp' directory so
that the behavior of that directory would be more like other
platforms.

A temporary file system is created with the "Create User-Defined
FS (CRTUDFS)" command using a new naming convention. The names of
permanent UDFS's must end with ".udfs". The names of temporary
UDFS's must end with ".tmpudfs", for example:

CRTUDFS UDFS('/dev/QASP01/new.tmpudfs')

The creator of a temporary UDFS must have *ALLOBJ special
authority. Temporary UDFS's can only be created in the system
auxiliary storage pool (ASP). That is, they can only be created
in '/dev/QASP01'.

After it is created, the temporary UDFS can then be mounted and
used much like a permanent UDFS, with the following restrictions:

- Temporary objects cannot be secured by authorization lists.
- User journaling of temporary objects is not allowed.
- Objects cannot be saved from, nor restored into, a temporary
file system.
- Extended attributes are not supported for temporary objects.
- Object signing of temporary objects is not allowed.
- You cannot mount a temporary UDFS as a read-only file system.

Users of temporary file systems should also be aware of the
following considerations:

- The storage for temporary objects is not accounted to the
owning user profile nor to any process. Therefore, it is possible
for a user profile to create temporary objects that exceed the
maximum storage allowed for that user profile.
- When any file system is unmounted, it can cause delays in
other processes that are attempting to access mounted file
systems, including system-supplied file systems such as QDLS
or QSYS.LIB. Normally these delays are very brief and are
not noticeable. When a temporary UDFS is unmounted, all of the
contents of the UDFS are deleted. If there are large numbers
of objects in the temporary UDFS, other processes could
experience significant delays accessing other file systems.
If you are affected by this consideration, it is recommended
that you use the Remove Directory (RMVDIR) and Remove Link
(RMVLNK) commands as needed to delete the contents of the
temporary UDFS before unmounting. The new SUBTREE(*ALL)
value for the RMVDIR command can be especially helpful in
this regard.
- Because unmounting a temporary UDFS deletes the entire
contents of the UDFS, the unmount is subject to many of the
same restrictions as the Delete User-Defined FS (DLTUDFS)
command. The unmount will fail if any of the following are
true:

- The user does not have *OBJEXIST authority to all of the
objects in the UDFS
- The user does not have *WX data authority to all of the
non-empty directories in the UDFS.
- Any object in the UDFS is checked out.
- Any object in the UDFS is read-only.
- The "restricted rename and unlink" attribute of a
directory is "Yes", and the user is not the owner of the
directory, does not own all the objects in the directory,
and does not have *ALLOBJ special authority.

When the unmount fails for any of these reason, diagnostic
messages will appear in the job log stating the reason for
the failure, along with a message stating how many objects
have been removed. That number will almost always be zero.
- The Reclaim Storage (RCLSTG) command automatically forces
all mounted file systems to be unmounted. This automatic
unmount will attempt to delete all objects in a
temporary file system. As described above, this may take
a long time if there are many objects in a temporary file
system. Additionally, this unmount may fail as described
above if some of the objects in the file system cannot be
deleted. In turn, this will cause the RCLSTG command to
fail. The file system will remain mounted and usable.
The problems causing the failure must be corrected before
using the RCLSTG command again.
- The block special file (BLKSF) object associated with the
temporary UDFS is itself a permanent object. It is only the
contents of the UDFS that are temporary. However, this BLKSF
cannot be saved nor can its attributes be changed to allow it
to be saved.
- This PTF only provides basic enablement of temporary file
systems. There will be changes in a future release to provide
further support, including new API functions, command help
updates, and System i Navigator enhancements.


Default Instructions

THIS PTF CAN BE APPLIED IMMEDIATE OR DELAYED.



Supersedes

PTF/FIX NO(S).  APAR TITLE LINE
--------------  ------------------------------------------------------------
     NONE

Summary Information

System..............................i
Models..............................
Release.............................V6R1M0
Licensed Program...............5761SS1
APAR Fixed..........................SE37352
Superseded by:......................
Recompile...........................N
Library.............................QSYS
MRI Feature ........................NONE
Cum Level...........................C0047610


System i Support

IBM disclaims all warranties, whether express or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. By furnishing this document, IBM grants no licenses to any related patents or copyrights. Copyright © 1996,1997,1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 IBM Corporation. Any trademarks and product or brand names referenced in this document are the property of their respective owners. Consult the Terms of use link for trademark information.

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG15V","label":"PTF Cover Letters - OS\/400 General"},"Component":"","ARM Category":[],"Platform":[{"code":"PF012","label":"IBM i"}],"Version":"V6R1M0","Edition":"","Line of Business":{"code":"","label":""}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG16A","label":"PTF Cover Letters - i5\/OS V6R1 environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF012","label":"IBM i"}],"Version":"V6R1M0","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
03 September 2009