Symptom
High paging can be seen in ST06 or with operating system tools when massive I/O operations (e.g. database backup) take place.
The performance of the system is not significantly worse in this time frame.
The performance of the system is not significantly worse in this time frame.
Other Terms
paging online backup Windows NT brbackup
Reason and Prerequisites
Some operating systems cannot distinguish between I/O from/to the
pagingarea and normal I/O from/to files. They count every I/O operation
as paging.
This can lead during a DB backup of a 90 GB database performed in 3 hours to ADDITIONAL displayed but to "real paging" of 30 GB/h which can be factors more than the "real paging".
This behaviour can be easily reproduced e.g. on WINDOWS OS by copying a large file and parallel observing the "page in" rates in the NT performance monitor.
Solaris e.g. on the other side shows as paging only moved virtual memory pages.
This can lead during a DB backup of a 90 GB database performed in 3 hours to ADDITIONAL displayed but to "real paging" of 30 GB/h which can be factors more than the "real paging".
This behaviour can be easily reproduced e.g. on WINDOWS OS by copying a large file and parallel observing the "page in" rates in the NT performance monitor.
Solaris e.g. on the other side shows as paging only moved virtual memory pages.
Solution
If you observe both symptoms together check if there are massive I/O
operations taking place in the timeframe observed. If so ignore these
values and check the paging in time frames when no massive I/O
operations take place. Normal access to datafiles is not counted as
massive I/O operation.
Header Data
| Released On | 05.02.2004 07:58:21 | ||
| Release Status | Released for Customer | ||
| Component | BC-DB-ORA Oracle | ||
| Other Components |
| ||
| Priority | Recommendations / Additional Info | ||
| Category | Consulting |
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