by Few days back, I was just experimenting the backup utility with
different parameters and observed few things.
Observation:
Backup file size increases the backup buffer size increases and also
by including Parallelism parameter.
Please note that there were NO connections to the database during this
exercise. Also time taken for backup is almost same for all cases.
Can anyone explain me why is this difference? Is something going wrong
with the data ? I am worried about data integrity.....
Here is my observation:
Case 1 :- Backup up with 4 buffers and buffer size is 2048 with
Parallelism 2
-rw-r----- 1 inst1 db2iadm1 2055241728 Aug 23 22:53
DBNAME.0.inst1.NODE0000.CATN0000.20020823224712.001
Case 2 :- Backup up with 4 buffers and buffer size is 4096 with
parallelism 2
-rw-r----- 1 inst1 db2iadm1 2080407552 Aug 23 23:03
DBNAME.0.inst1.NODE0000.CATN0000.20020823225642.001
Case 3 :- Backup up with 8 buffers and buffer size is 8192 with
parallelism 2
-rw-r----- 1 inst1 db2iadm1 2113961984 Aug 23 23:13
DBNAME.0.inst1.NODE0000.CATN0000.20020823230642.001
Case 4 :- Backup up with 4 buffers and buffer size is 2048 with
parallelism 2 (exactly same as Case 1)
-rw-r----- 1 inst1 db2iadm1 2055241728 Aug 23 23:28
DBNAME.0.inst1.NODE0000.CATN0000.20020823232202.001
Case 5 :- Backup with default parameters WITHOUT parallelism.
-rw-r----- 1 inst1 db2iadm1 2046853120 Aug 23 23:37
DBNAME.0.inst1.NODE0000.CATN0000.20020823233023.001
Case 6 :- Backup with default parameters WITH parallelism 2.
-rw-r----- 1 inst1 db2iadm1 2051047424 Aug 23 23:45
DBNAME.0.inst1.NODE0000.CATN0000.20020823233915.001
Case 1 to Case 2 : 25 MB size difference
Case 2 to Case 3 : 33 MB size difference
Case 5 & Case 6 : Increase in size of about 5 MB just by having
parallelism.