When executing data archiving you have to be acting careful. The data archiving write and delete processes can be consuming a lot of CPU power from the database. Also, if you are not careful you might, by accident, claim all background processes. This blog will explain how to limit the amount of batch jobs used for data archiving. The data archiving run process itself is described in this blog.
Questions that will be answered in this blog are:
How can I limit the amount of deletion jobs?
How can I restrict the archiving jobs to run on a specific application server only?
Limit amount of deletion jobs
When the write run of data archiving is finished, this can have delivered many files. If you are not careful with the deletion, you select all files and each file will start a deletion run. This will consume a lot of CPU power on database level, since the deletion run will fire many DELETE statements to the database in rapid sequence. Also you might consume all batch jobs, leaving no room for any business batch job.
In stead of running the deletion from SARA, you can also run the deletion via program RSARCHD:
With this example, MM_EKKO files will be deleted. Maximum of 50 files from 1 archiving run will be processed, with a maximum of 2 deletion batch jobs running at the same time.
This blog addresses the main challenge in SAP data archiving for functional object: the discussions with the business.
This blog will give answers to the following questions:
When to start data archiving discussion with the business?
How to come to good retention periods?
What are arguments for not archiving certain data?
Data archiving discussion with the business
Unlike technical data deletion, functional data archiving cannot be done without proper business discussion and approval.
Depending on your business several aspects for data are important:
Auditing and Sox needs
Tax and legal retention periods
Product data requirement
And so on…..
Here are some rules of thumb you can use before considering to start up the business discussions about archiving:
Rule of thumb 1: the system is pretty new. At least wait 3 years to get an insight into which tables are growing fast and are worth to investigate for data archiving.
Rule of thumb 2: if your system is growing slowly, but the infrastructure capabilities grow faster: only perform technical clean up and don't even start functional data archiving.
Rule of thumb 3: if you are on HANA: check if the data aging concept for functional objects is stable enough and without bugs. Data aging does not require much work, it is only technical and it does not require much business discussions. Data retrieval from end user perspective is transparent.
Data analysis before starting the discussion
If your system is growing fast and/or you are getting performance complaints, then you need to do proper data analysis before starting any business discussion.
Start with proper analysis on the data. Use the TAANA tool to get insights into the data: how is the distribution of data per document type, per year, per plant/company code etc. If you want to propose retention period of let’s say 5 years, you can use the TAANA results to show what percentage of data you can move out of the database.
Secondly: if you have an idea on which data you want to archive, first execute a trial run on a recent production copy. There might be functional blocks that prevent you from archiving data (like not closed documents).
Third important factor is the ease of data retrieval. Some object have a nice simple data retrieval function, and some are really terrible. If the retrieval is good, the business will more easily accept a shorter retention period.
As last step you can start the business case: how much data will be saved (and how much money hence will be save) and how much performance would be gain. And how much time is needed to be invested for setting up, checking (testing!) and running the data archiving runs.
In practice data archiving business case is only present in very large systems of 5 TB and larger. This sizing tipping point changes in time as hardware gets cheaper and hourly manpower costs go up.
The discussion itself
Take must time in planning for the discussion itself. It is not uncommon that archiving discussions take over a year to complete. The better you are prepared the easier the discussion. It also helps to have a few real performance pain points to get solved via data archiving. There is normally a business owner for this pain point who can help push data archiving.
This blog will explain how to execute a data archiving run.
Questions that will be answered in this blog are:
Which settings do I need to make or check before data archiving run?
How to perform the data archiving run?
How to validate the data archiving run?
How to retrieve that archived data?
This blog assumes you have finished the basic technical data archiving setup as described in this blog. It also assumes you have made agreements with your business on the retention periods. For more information and tips on discussions with the business teams on data archiving, read this blog.
Functional data archiving example: purchase requisitions
To explain the functional data archiving we will use Purchase Requisitions as example. Technical object name is MM_EBAN.
To see which tables are archived hit the Database Tables button. Here you can see the list of tables from which data potentially be archived:
If you want to see the other way around, which table is used in archiving objects, do put in the table as entry point, to retrieve list of archiving objects. In this example archiving objects that delete from table EBAN:
Dependency of objects
By clicking the top left button on the archiving object you get the archiving dependency view. For MM_EBAN this is pretty simple: it has no dependencies.
As example for dependencies this is the overview for sales orders (SD_VBAK):
Here you can see that before you can archive sales orders, you should archive the billing documents first. And for the billing documents, you should archive the deliveries first.
Functional archiving settings
First we have to make or check the object specific functional archiving settings.
In the case of purchase requisitions we have to set the retention periods per document type:
Some archive object have a pre-processing step. MM_EBAN has one as well. In this step data is selected and marked for archiving (many times by setting deletion flag or other indicator).
In the step create the variant (give it a useful name) by putting in the name and pressing Edit. On the next screen fill out your data select the log level. Go back to the first screen and select the start data and spool parameters. When both lights are green, hit the execute button. When you click the job log button you check for the results.
Example of result of pre-processing run:
As you can see not all selected data is archived. Transactions that are not completed from business point of view will not be flagged for archiving.
If you have done the pre-processing step, continue with the write step. Principle is the same: select the data and log level. Important in the write step is to correctly fill the Archiving Session Note with a useful text. This text is put as label on the archive file for later retrieval:
When done plan the job and execute. Result looks like:
Pending on your technical system settings the file will be stored automatically or you still need to do this manually.
If you have setup the system to store files in content server, you first have to execute storage run. For more details see this dedicated blog.
Finally we can now start the deletion run: the actual clean up of old data happens now.
Select the data files you want to archive and start the run.
Word of care with deletion: please don't select too much files and subsection in one go. Each file sub section will result into a deletion job. The deletion will put significant load on the database, since it will be pushing out a lot of data. If you are not careful you will launch easily 20 or more heavy deletion jobs that run in parallel and that might severely decrease system performance.
Result of archiving deletion run:
Checking archive result
The result checking is possible by looking at the technical correctness of the archive file.
In the archiving object choose the Overview button. Then select the archive file you want to inspect. A correct file should like like this:
In the testing phases and first production runs, you also want to do record counting. A good way is to run the TAANA transaction for key tables you want to archive before the archiving and after the archiving. The difference should match the deletion counter on the write and deletion logs. If you find differences: check for bug fix OSS notes.
Retrieving archived data is different per archived object. Some retrieval is nicely integrated into the normal transaction. Some require extra transaction to run. Some retrieval is via special program.
Data retrieval of purchase requisitions can be done via SARA and choosing the read option.
Here you first need to manually select the archive files to read from (see I did not give the note and regret it, since the file has no meaning now…):
Result after reading looks like this:
Controlling amount of parallel batch jobs
The deletion phase of archiving can lead to uncontrolled amount of parallel batch jobs. See this dedicated blog on how you can control it.
Data archiving run statistics
Transaction SAR_DA_STAT_ANALYSIS can be used to collect statistics on the data archiving runs:
This blog will explain the general technical setup to be performed for SAP data archiving.
Questions that will be answered in this blog are:
Which generic settings do I need to make for data archiving in the technology domain?
Why should I use a content server to store archive files?
For getting insights in what to archive, read this dedicated blog first.
Data archiving content server setup
For data archiving you can use the file system for storing the archive files. This you can do to perform initial testing. For productive use it is best to store the archive files in a content server. It will not be the first time an overzealous basis person in need for file storage deletes some old files in a directory called /archive…..
After you install the content server, set up in OAC0 the customizing for the content server to use it for Archivelink: