Re: High priority I/O with IFS MOV

[Luis Rodriguez <luisro58@xxxxxxxxx>]

I wonder if using Qshell's MV would be better?

Regards,

Luis

Sent from my Moto G phone. Please excuse my brevity.

On Dec 1, 2016 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
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