Re: Best Practice Question

Patrik,
/tmp is not automatically cleared at IPL time. IBM tells you that if you
want to, you can modify the startup program to do so. I just read this
today again but I've already lost the link (and the urge to go find it
again).

There are numerous things in the IFS which cannot be saved, even if done in
a restricted state, because they will be locked by active tasks. So,
instead of people getting such failure messages in their joblogs IBM
started flagging certain directories as *ALWSAV *NO.
And stuff that will never be backed up successfully on an active system
(keeping in mind that, for the ifs, IBM's save while active is a sick joke)
is often flagged as *ALWSAV *NO. This often includes certain expendable
web logs.

There are those who have made it their personal mission to search out that
particular attribute in all IFS entries and change it to be allowed in a
save. I disagree with them. But we don't work at the same shop and, thus,
it is no skin off my teeth.


On Wed, Aug 20, 2025 at 1:59 PM Patrik Schindler <poc@xxxxxxxxxx> wrote:

Hello Dan,

Am 20.08.2025 um 19:40 schrieb Dan Bale <dan.bale@xxxxxxxxxxxxxxxxxxxxx>:

Can anyone provide context for why "Can be saved: No" for /tmp is

considered a best practice?

/tmp is meant for files being created in a temporary manner. Ideally, they
should be deleted by the generating application when no longer needed.
Setting applications to debugging state, or (unexpected) application
crashes happening might prevent cleanup.

See also:
https://en.wikipedia.org/wiki/Unix_filesystem#Conventional_directory_layout
(scroll to /tmp)

Due to their intended temporary nature, files in /tmp by themselves often
have no value, because their content is often derived from data being in
permanent storage anyway, and serves no other need than to conveniently
tuck away intermediately processed data somewhere where it can be picked up
by a subsequent program for further processing. This is to support of the
Unix mantra of "Make each program do one thing well." and helps to chain
many different such tools to perform complex operations on data. Not each
scenario can be implemented by a linear chain of "pipes".

https://en.wikipedia.org/wiki/Unix_philosophy

https://en.wikipedia.org/wiki/Pipeline_(Unix)

All in all, /tmp is not unlike QTEMP, but global in nature and often gets
erased when rebooting Unix-like OS.

Does that help in understanding?

Is "Can be saved: Yes" the shipped default

For 7.3: Yes.

and, ergo, are most shops oblivious to the potential impact of this

setting?

Probably.

I feel the setting of "Can be saved: No" by IBM is somewhat excessive when
considering the IFS in general, but for /tmp and even /var/tmp (same as
/tmp but not erased at reboot time), it makes sense that the content isn't
backed up.

:wq! PoC


--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
To post a message email: MIDRANGE-L@xxxxxxxxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: https://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxxxxxxxx
Before posting, please take a moment to review the archives
at https://archive.midrange.com/midrange-l.

Please contact support@xxxxxxxxxxxxxxxxxxxx for any subscription related
questions.