SAP Migration Best-practices

8/10/2019 SAP Migration Best-practices

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Prerequisites Best practices for SAP system migration



Contents

Production Architecture ............................................................................................................................... 3

Target OS User ID prerequisites ....................................................................................................................4

Target File System Requirements .................................................................................................................4

Target Database Prerequisites ......................................................................................................................5

Migration best practices ............................................................................................................................... 5

Reference OSS notes .....................................................................................................................................6

Production Architecture ............................................................................................................................... 3

OS User id prerequisites ............................................................................................................................... 4

File System Requirements............................................................................................................................. 4

Database Prerequisites ................................................................................................................................. 5

Migration prerequisites ................................................................................................................................ 5

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Production Architecture

A typical production system setup looks like below

MSG Server/

ENQ ServerERS

SAP

Appl

Server 1

SAP

Appl

Sever 2

DB - RAC

Node 1

DB - RAC

Node 2

SAPCTL SAPCTL

2 node RAC

with ASM

SAP ASCS/ERS

Communication

/sapmnt

NFS server

It contains below set of servers



1. Two ORACLE RAC nodes

2.

Minimum two application servers3. One NFS mount server for /sapmnt mount point

SCS/ASCS service and enqueue replication will be on two ORACLE RAC nodes. SAPCTL is used to achieve

high availablityavailability.

Target OS User id ID prerequisites

1. Uid of the below users should be same in all the above mentioned servers

<sid>adm

sapadm

oracle

daaadm

<sidadm> should have properties (default group: sapsys, /bin/csh/, “SAP System Administrator”)

2. gid of the below groups should be same on all the servers

sapsys

Target File System Requirements

Below mount points are required on the servers

Application servers

a. /sapmnt - 5 GB

b. /sapmnt/<SID> - NFS mount from NFS server

c. /oracle – 10 GB

d. /usr/sap – 10 GB

e. /usr/sap/DAA – 10 GB

f. /usr/sap/<SID> - 20 GB

Database servers

a. /sapmnt/<SID> - NFS mount from NFS server

b. /usr/sap – 10 GB

c. /usr/sap/<SID> - 20 GB

d. /oracle – 20 GB

e. /oracle/<SID> - 10 GB

NFS mount server

a. /sapmnt/BP4 – 10 GB



Export this mount point to all database and application servers with option

(rw,sync,no_root_squash)

Target Database Prerequisites

Check if below ASM disk groups have sufficient space with reference to source DB

<SID>_ACFS

<SID>_ARCH

<SID>_DATA

<SID>_FRA

<SID>_MLOG

<SID>_OLOG

Migration prerequisitesbest practices 1. Update R3load, R3ldctl, R3szchk executables to latest version in Kernel 700.

2. Update DB stats of source.

3. Identify top 50 tables (size > 10 GB) in source for splitting. (attached)table_list.txt

4. For oracle to oracle migration, use PL/SQL splitter with ROWID splitting option for normal tables.

5. Split cluster tables with key fields, Not rowid (refer from R3ta_hints.txt)R3ta_hints.txt

6. For tables with ROWID splitting, import option ‘loadprocedure fast’ is MANDATORY.

7. Create export order file for splitted tables, 2 consecutive splits of same table should be placed as

far as possible.8. Tune DB parameters for source and target using note 936441:

Source DB

a. pga_aggregate_target = 40% of main memory (for source database) 32GB x 40% =

12.8GB

b. db_cache_size = 50% of main memory size (for source database) – 32GB x 50%

= 16GB

c. PSAPTEMP should have empty space equal to 20% of DB used space. add 32GB file

(current size is 66 GB)

Target DB

d. pga_aggregate_target = 70% of main memory (for target database)

e. db_cache_size = 20% of main memory size (for target database)

f. Oracle log_buffer = 43,614,208as per SAPnote

g.

Oracle parallel_max_servers = as per SAPnote485

h. parallel_execution_message_size integer as per SAPnote 16384 – ok

i. pga_aggregate_target big integer 22G – ok

j.i. workarea_size_policy string AUTO – ok



k.j. db_writer_processes integer 1

l.k.

sessions = as per SAPnote1000 m.l. processes = as per SAPnote750

n.m. redo log size = 1 to 2GB

o.n. PSAPTEMP add 100GB spaceshould be 20% of DB size.

9. Options to choose in SAPINST:

a. Table splitting preparation

i. PL/SQL splitter

ii. Number of parallel jobs = 8

iii. List of tables to split, criteria (attached)

b. Export options:

i. Split STR files

ii. Packages larger than 1 GB

iii. Use Unsorted unload

iv.

Parallel export/importv. Package unload order

c. Import options:

i. Instance RAM: (Total RAM – 20% OS overhead – ASM memory)/number of

instances per host24 GB

ii. MaxDataFilesize = 31000

iii. Advanced DB config:

1. Create tablespaces: Assign smaller datafiles (2 GB) to each tablespace

with autoextend to 20 or 30 GB and similar MaxDatafileSize. Total size

of all data files (at Max size) should approximate the final DB size.

Distribute the data files evenly across all SAPDATA directories to avoid

the file system reaching 100% capacity. (for PRD, 21 datafiles of 30 GB

each in all 8 sapdata directories, total 168 datafiles.)

2.

Autoextent: all tablespaces should have autoextent3. Change init.ora: adjust oracle params as above

4. Number of parallel jobs: 2 * no. of CPU’s (adjust depending on total CPU

and number of packages after splitting)15

5. Parallel export/import

6. Special package order

d. Apply oracle patches immediately after installing oracle.

10. Running DB stats with multi-threading: brconnect -p initQAS.sap -l E -U -f stats -t all -g 32 -p 32

Reference OSS notes784118 - System Copy Tools for ABAP Systems

455195 - R3load: Use of TSK fi les

936441 - Oracle settings for R3load based system copy954268 - Optimization of export: Unsorted unloading

1654937 - How to correctly build the SAP Netweaver Kernel Media



1875778 - Performance Optimization for System Copy Procedures

1139396 - Temporary database objects in BW 7.X

SAP Migration Best-practices

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