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What does "quiessing" the system mean?

I had read about doing a save-while-active backup that referred to "quiessing" the system, keeping users off for about ten minutes and setting a focal point for restores. I have looked all over the suggested IBM resource, SC41-5304, but am still not sure what it means to "quiess" the system. Can you give me something more concrete on this? Also, does SWA necessarily involve journaling? That is what it looks like in the IBM documentation and I have not done any journaling before AND I certainly cannot figure it out from IBM's documentation. Thank you very much.

I believe that quiesce is a French word. In the context of an iSeries backup, it means, "to bring the system to a quite state". One in which there is very little activity occurring on the system. This is not the same as a "restrictive state", which as you know, is required for a SAVSYS process.

There is a very important difference between quiesced and restrictive states. If you don't take the system down to a restrictive state, you can still run a backup process as an unattended batch job.

Prior to starting my unattended backup process I end the following subsystems:

QINTER, QSPL, QHTTPSVR, QSNADS, QSVCDRCTR, QSERVER and QUSRWRK.

I also end the Mail Server Framework via the ENDMSF command.

I'm now in a "quiesced state".... Note, my backup process is still running in the QBATCH subsystem.

In my opinion, it is very important that you have journaling active for any backup/recovery process. If you don't, you can never recover any changes made between backups. However, it isn't a requirement of SWA if you "quiesce" the system prior to starting the backup. One a synchronization point has been established by the SWA process, you can resume normal system operations. If you had to use these backup tapes to recover from a disaster though, you would only be able to recover to the time of the SWA synchronization. If you had journaling active you would be able to recover to the point of your last journal receiver backup.

Setting up journaling isn't very difficult. I journal all physical files in our production data libraries.

Here is an example of how I have defined the journaling environment on my V4R5 system. I store journal receivers in a separate library and in a separate user ASP... In this example, I also have defined remote journaling to another AS/400 so all journal transactions are immediately saved off the production system.

Journaling - Setup

1. Create a message queue to receive journal messages:
CRTMSGQ MSGQ(QGPL/LAWJRN) TEXT('Lawson journal messages')

2. Create a journal receiver in the proper journal receiver library:
CRTJRNRCV JRNRCV(JRNRCVLAW/LAW2JR0001) THRESHOLD(500000)

3. Create a journal referencing the receiver just created:
CRTJRN JRN(LAWP1FILES/LAWP1JRN) JRNRCV(JRNRCVLAW/LAW2JR0001) MSGQ(QGPL/LAWJRN) MNGRCV(*SYSTEM) DLTRCV(*YES) RCVSIZOPT(*RMVINTENT *MAXOPT1)

4. Create a remote journal:
ADDRMTJRN RDB(S17) SRCJRN(LAWP1FILES/LAWP1JRN) TGTJRN(S02RMTJRN/LAWP1JRN) RMTRCVLIB(S02RMTJRN) TEXT('Remote journal for LAWP1FILES')

5. Start journaling for all files in the library:
STRJRNLIB LIB(LAWP1FILES) JRN(LAWP1FILES/LAWP1JRN) IMAGES(*AFTER) OMTJRNE(*OPNCLO)

Note: This is a TAATOOL command that determines all physical files in a library and then executes the STRJRNPF command against each one. Only AFTER images are recorded and entries for file open and closes are omitted from the journal record.

Add a step to your backup process that generates a new receiver just prior to running your backup process:
CHGJRN JRN(LAWP1FILES/LAWP1JRN) JRNRCV(*GEN)

I also run STRJRNLIB command prior to starting a backup just to insure that any newly added or replaced files are journaled before I start a SWA backup.


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