Shadow Instance Calculation in SUM Tool

[Mithran]

Dear Guru's,

Thanks in Advance.

Could you please help me in understanding SUM Phase for Shadow Instance switch.

What happens exactly during switch over in SUM shadow instance phase. What happens for the business transactions running in original system. I have read articles regarding shadow instance But still need few answers.

For example if we do a HR pack update,

1. whether sum creates a shadow instance with respect to HR pack update related tables or it creates an entire copy of original system all tables?

2. During switch over, what happens to the last transaction whether it will be copied to shadow instance and rewritten to original system?

3. what would be the requirements for starting SUM with shadow instance, how much space required and how to calculate it

example: application size is - 64 GB of ram and /usr/sap/ -> directory is of 60 GB

database is of 6 TB and data mount point has over 12 TB

we are running on HANA Database 1 SPS 12

4. SUM will be creating shadow instance both in application and database right? additional space how much will be required?

Thanks & Regards,

Mithran

[dasistdochscheisse]

and addition to what was said before: If you just import some SP, imo SPAM is the transaction of choice. Much faster and does not need additional diskspace for a "shadow db".

I did a SP update in our BW system and included was an update of SAP_UI. In this case i used SUM on the second system, because SAP_UI patches are huge and they take forever to get installed. It was about 2 days with an update from 4.53 to 4.54 plus the available patches, i forgot to increase the number of parallel processes in SAPM. On the second system, the whole SUM process incl. downtime was about 14 hours.

But for just some SP, i would use SPAM all the time.

[Boris_Rubarth]

Hi Mithran,

in addition to what S Sriram has written: maybe the following blog post provides helpful background:https://blogs.sap.com/2014/04/02/sum-introduction-to-shadow-system/
This may help you to distinguish between the shadow instance on Application Server level and the shadow repository on database level. The shadow repository does not contain customer business data, so the size is independent on your db size.

You find the SUM guide listed on this page: https://help.sap.com/viewer/c4ebc2b5d928446180d9ad2667f11faa/1.0/en-US/a151c8571e0c46b0a4098eda8d343...

Regards, Boris

[Sriram2009]

Hi Mithran

1. During the upgrade, the shadow instance required tables to be copied and do the upgrade in the shadow instance uptime activities, during the downtime it will update the original instance..

2. During the switch, all the last transaction data are intact in the original instance

3. Disk space on SUM directory 50 to 100 GB & DB 20 to 30 % size of your DB. based on your DB you can check the latest SUM guide.

4. Yes, the SUM process will create the shadow instance, disk space question already answered point number 3

Regrads

SS