Colin,

I agree, in the shops I have worked, /tmp and /dev are using a tmp zFS or 
memory. When the LPAR is IPL'ed, then /tmp is "rebuilt" at IPL time. 

But one question, which I don't know the answer to, can the JVM shared library 
be shared between LPAR or is it LPAR specific.  I am leaning towards LPAR 
specific because by default it is /tmp.  If that is the case, then I would 
probably put it in /var.

Just curious. 

Thanks,
Jerry 

-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of 
Colin Paice
Sent: Thursday, June 4, 2026 12:11 AM
To: [email protected]
Subject: [EXTERNAL] Re: unix file permission question

One thing to think about is you want the shared library directory to persist 
across IPLs, so perhaps /tmp is not the best place to have it.

If you create the shared library there may be little or no performance benefit 
for the first jvm start.  The benefit comes on the subsequent  jvm starts.

If you start WAS(say) once per ipl and it has its own dedicated shared library, 
then you may get no benefit.

I changed zowe start up to save the shared library as part of its shutdown, and 
restore the shared library as it's first step.  There are multiple jvms in 
zowe, and this sped up my zowe starts

Colin

On Thu, Jun 4, 2026, 02:02 Andrew Rowley < 
[email protected]> wrote:

> On 4/06/2026 1:07 am, Pommier, Rex wrote:
> > There is another task trying to use the shared directory and that's 
> > what
> caused me to ask in the first place.  Somebody tried to run a Strobe 
> session that wanted to write to the shared directory and it got 
> stopped by the incorrect permissions.
>
> I tried to find out more information on this directory. It appears on 
> other platforms it is typically located somewhere owned by the user, 
> rather than in /tmp. I also found a document:
>
>
> https://urldefense.com/v3/__https://www.ibm.com/support/pages/question
> s-about-files-under-tmpjavasharedresources-folder__;!!PEZBYkTc!f0D7lJh
> Asy1AJOTJhLy-vsU2EWBCFM6cjUwHMc6pwdw7ffn-dylTGwwCWnTbGV8bVZJzIxEi-nLNj
> U7JZT7hQ1lje5WFAvMidUNHhA$
>
> That seems to imply that /tmp/javasharedresources should be treated 
> like /tmp. Probably the best solution is to create it at IPL as Bob 
> Hansel suggested, but also change ownership to root just in case 
> somebody else created it first.
>
> The umask of tasks using the directory shouldn't matter.
>
> --
> Andrew Rowley
> Black Hill Software
>
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