I am planning to mount the version (and sysplex root) file systems as
read only as per IBM's recommendations. I was curious about the expected
benefits on assigning read/write application related file systems to
specific systems or just accept the default and let the system reassign
ownership based on file system performance characteristics.
Mark Jacobs
On 06/16/11 09:44, Mark Zelden wrote:
One point is, that all access to the physical file system has to be
coordinated by the owning system. So when the task is executing on the
owning system then no problem. But when it execs on another system, then
there will be some overhead in communicating (literature reads about
function shipping). The actual I/O will be done by the owning system. So
when you know the majority of tasks is running on one system, give this
system the ownership. This is valid for all types of physical file systems
and available for years in sysplex shared HFS (I think z/OS was called
OS/390 that time). This type of ownership is called the "Unix Owner". The
physical file systems do not need to know about whether they are running
in a sysplex or not.
One thing not mentioned above and in the prior post (this applies to
HFS and zFS): If the file system is mounted read only, then the I/O
can be done by the local system and does not have to be function
shipped. So only mount file systems R/W if you have to. I have
found that many people outside of the "MVS" team don't realize this
and request BPXPRMxx updates or mount product root file systems
R/W when they only need to be R/O. The SMP/E controlled product
root is all that needs to be R/W.
--
Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS
mailto:[email protected]
Mark's MVS Utilities: http://www.mzelden.com/mvsutil.html
Systems Programming expert at http://expertanswercenter.techtarget.com/
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--
Mark Jacobs
Time Customer Service
Tampa, FL
----
Some people are electrifying, they light up
a room when they leave.
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