Re: High priority I/O with IFS MOV

[DrFranken <midrange@xxxxxxxxxxxx>]

No NFS. I set this up and is a straight MOUNT of the UDFS.


        - 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 10:15 AM, Aaron Bartell wrote:
> Is IFS Journaling turned on?
>
> Does anyone know if NFS is used for ASP?  I ask because I tried to mount an
> NFS from one folder to another on the ~same~ IBM i and had significant CPU
> issues.
>
> Aaron Bartell
> IBM i hosting, starting at $157/month.  litmis.com/spaces
>
>
> On Thu, Dec 1, 2016 at 9:10 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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