My poor and limited experience with DLm was related to performance:
I started with single data stream (IEBDG job or similar).
Obviously there was a point of saturation, I mean adding next data
stream did not increase overall throughput. Even decreased it slightly.
Of course adding any workload to a hardware box will decrease it for
other tasks. This is another variant of "there is no free lunch"
proverb, IMHO.
However there is simple solution for that: just take care about the
schedule. Do not start heavy tasks concurrently.
I know, easy to say but sometimes hard to do. :-)
Last, but not least: Michael pointed important difference - I mean ATL
and MTL definitions.
--
Radoslaw Skorupka
(looking for new job)
Lodz, Poland
W dniu 04.03.2021 o 17:24, Michael Watkins pisze:
"Will there be a impact to mainframe backup when there is a high backup volume for
open system ?"
I am employed by the Texas CPA where such a solution was implemented. We never
experienced any problems with contention. First, our z/OS mainframe necessarily
had its own MTree file structure on the Data Domain, so there was no contention
at the file level. The mainframe activity at this installation is characterized
by a couple of bursts of activity each week while the open systems activity is
more distributed through out the week, so the performance of the Data Domain
has never been challenged.
NB: The DLm emulates a manual tape library. An IBM TS7000 is an automatic
library.
NB: The TS7000 is capable of communicating directly with an IBM DS8000-class
storage frame. The DLm is not.
Two caveats: (1) The TS7000 communicates with z/OS tape management software.
The DLm does not. This complicates tape management. (2) If you are
contemplating the achival of mainframe data on cloud storage using IBM's Cloud
Tape Connector (CTC) solution, the DLm will not be able to do this. It will
also complicate implementation of IBM's Transparent Cloud Tiering (TCT).
I don't believe you can find someone more knowledgeable about of Data
Domain/DLm implementations than Carl Swanson.
-----Original Message-----
From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of
Carl Swanson
Sent: Thursday, March 4, 2021 8:18 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: EMC DLM over IBM VTL
CAUTION: This email originated from outside of the Texas Comptroller's email
system.
DO NOT click links or open attachments unless you expect them from the sender
and know the content is safe.
First full disclosure I work for Dell Technologies but more
specifically in the DLm group, now with that out of the way.
Probably more than 50% of the DLm customers do share their backend
(Data Domain) storage with the distributed world and or the IBM-I world. What
this means is we have experiences in sizing these types of solutions. When we
perform this sizing, we will do a study on the mainframe the distributed side
and the IBM I if required. We then make sure that the performance
characteristics of the back end storage array is capable of handling the peak
workload without issue. From the DLm point of view this is the connection to
the mainframe and we size the performance requirements based on the supplied
RMF data .
I can provide much more detail if you like just not sure if it is
appropriate to do so on list. Below is my non work email, but most could
probably figure out my work email.
Final answer this is a common for DLm systems and works great the key
is proper sizing which my group handles.
Carl Swanson
Mobile:215.688.1459
Email: carl.swans...@verizon.net
-----Original Message-----
From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of
Jake Anderson
Sent: Thursday, March 4, 2021 1:16 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: EMC DLM over IBM VTL
Hello
We are analysing if EMC DLM would be a right fit to replace IBM VTL.
I am trying to understand about backup cycles using EMC DLM when we use single
backup solution and single virtual tape library to backup both mainframe and
open systems.
Is there a possibility for contention ?
Will there be a impact to mainframe backup when there is a high backup volume
for open system ?
These performance do effect the open system as well ?
Trying to understand these from the DLM users ? Any feedback would be
appreciated
Jake.
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