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Product and Topic Expert
Product and Topic Expert
This blog discusses the pipe mode used by Database Migration Option (DMO) of Software Update Manager (SUM). Before reading this content, be sure to be familiar with the general concept of DMO, explained in Database Migration Option (DMO) of SUM - Introduction

  • Both the heterogenous system copy of Software Provisioning Manager (SWPM) and DMO of SUM support the migration to SAP HANA Database
  • Both SWPM and SUM trigger R3load for the export from the source DB and the import into the SAP HANA DB
  • But DMO has both R3loads running on the same host: on the primary application server (PAS, fka central instance CI)
    (see DMO: technical background)

The "classical migration" (heterogenous system copy of SWPM) uses either the file mode or the socket mode.

Using the file mode, the data are exported, and written into a file, using compression. The file is transferred over the network:

Using the socket mode, the data are exported and transferred over the network:

Now with DMO, both R3load are running on the same host, and they communicate using the main memory of that host, using the pipe mode per default:

:!: Warning (Unix only)!

Do not use the statement grep* on the migrate_* directories to check for error messages. This generic grep statement may corrupt the named pipes used in R3load communication and cause errors in R3load processing. (Using “grep*.LOG” in these directories is not dangerous.)

Even with DMO, it would be possible to switch to the file mode. The R3load exports the data into a temporary file of limited size. As soon as this file is processed and the data are imported into the target DB, the temporary file is deleted.

    • Compression is used for creating the file
    • For windows OS, the pipe mode is enabled starting with SUM SP13 (available since April 28th 2015)
    • I have no scenario when you would want to switch from pipe to file mode.

Boris Rubarth
Product Manager, Software Logistics, SAP SE

[Update on June 1st 2015] File mode for DMO does use compression (this was initially wrongly stated in the blog).

[Update on March 15th 2016] Removed graphic for DMO file mode and shortened text; added warning on grep statement.