Ordinarily your response is the one I would use, that said, in an SAP
environment where SAP stores things in well, unique ways, then the question
begs the answer of experience.
Lots of libraries with SQL packages, a significant use of the IFS, data
spread around quite at bit. On the surface you might expect that the
smaller objects would benefit from a dual drive scenario.
In that light I was hoping for some experiential responses. Lacking any,
I'll presume it will help and go that direction.
--
Jim Oberholtzer
Agile Technology Architects
-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of
DrFranken
Sent: Thursday, August 29, 2019 11:59 AM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: SAP save with parallel drives
Obviously there are other things to consider but if it takes 18 hours to
write to LTO4 then they have more than a couple hundred GB of data *OR* a
fantastically bad DASD subsystem!
Assuming the prior (despite the lack of evidence) then saving to dual drives
is with near certainty going to help. Best cast of course would be 9 hours
but more likely 'about 12' would be my estimate and possibly as low as 10
best case. Some things like SAVSYS need to go to just one tape and that will
then include security which if badly done I've seen take 5+ hours all on its
own. Thus from the end of security best case is remaining time in half and
work up from there.
Given they are fiber you don't have the possibility of a 5901 card not being
able to drive two drives flat out, even a 5774 can push two LTO4s to the
limit so now you're down to disk I/O and sufficient memory. If they run SAP
they probably have plenty of both! LOL!
- Larry "DrFranken" Bolhuis
www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.
On 8/29/2019 11:05 AM, Jim Oberholtzer wrote:
One of my customers runs SAP on POWER.
We will be doing an OS upgrade on one of those partitions,(not
replicated) and we found out the save process to a single LTO4 fibre tape
was 18 hours.
Ouch.
We have tape library with multiple drive sleds in it, so my question
is; In a SAP environment does doing saves to parallel tape devices
help or hurt the performance of the save?
--
Jim Oberholtzer
Agile Technology Architects
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