Re: High priority I/O with IFS MOV -- MIDRANGE-L

If the PDF's never change could they not be moving them to the other
location by day instead of one large swoop at EOM.

On Thu, Dec 1, 2016 at 10:53 AM, DrFranken <midrange@xxxxxxxxxxxx> wrote:

I believe we tried MV from QSHELL and it failed due to the different file
systems. I will test that again.

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 12/1/2016 10:21 AM, Luis Rodriguez wrote:

I wonder if using QShell's MV command would be faster?

Regards,

Luis

On Thu, Dec 1, 2016 at 11:10 AM DrFranken <midrange@xxxxxxxxxxxx> wrote:

Customer has a process that accepts many (and I mean MANY) PDFs into the

iFS every day. During the month they go into a directory such as
'/www/zendsvr6/pdfdocs/abchst'. They are referenced by the web server.
They are PDFs and never, ever changed or deleted.

BUT at the end of the month they are moved by month into a dir like:
'/www/zendsvr6/pdfdocs/abchsta/2016/11/'

They are moved one at a time because there is a control file with all
the names AND the process runs while the system is still up. The process
uses the MOV command to move the documents.

In the past this worked great (for years now) and now on shiny new
Power8 it is very very slow. HOWEVER One other thing has changed.

The target directory ('/www/zendsvr6/pdfdocs/abchsta/') is now mounted
in a user ASP. That ASP is on larger slower disks. This makes perfect
sense because those documents are rarely if ever read and never go away.
Total document count is approaching triple digit millions in there.
Normal busy level on those disks approaches zero, all reads. There are
thirty (30) disks in ASP(2).

Now if it was only slow I would say: "Well yeah! It's actually COPYING
and DELETING the documents now because they are moving from *SYSBAS to
ASP 2, onto physically different disks, and they are slower." This would
make perfect sense and actually we wouldn't care much. The process
changes the control file as it goes so anyone looking them up gets the
document whether it has moved or not.

The problem is it's killing system performance overall. Even though this
process is running at priority 80 if you watch WRKSYSACT it constantly
is swapping to priority TEN (10). Overall cpu is well below 30% (of
four cores). There is a large amount of faulting and paging as well
which I think would be expected since all the documents are actually
being copied. The job currently run in a separate subsystem but is using
*BASE memory. *BASE is 1/4TB of memory.

Any thoughts on how to reduce the impact to the system here? Would a
CPY followed by a DEL be better than a MOV?

Would reducing the jobs timeslice help? It's at default of 5000.

--

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.
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