Filesystem Requests 
Definition
This submonitor in the SAP/Oracle Database Monitor lets you check filesystem requests in the Oracle database. It monitors the activity of filesystem requests with the Oracle GV$FILESTAT view
Use
You choose Detailed Analyses ® Overall activity ® Filesystem requests.
This monitor helps you to minimize the time needed to read or write data from or to a file, so that you can identify the frequently used data files and put them on separate disks to avoid contention, if necessary. Data file activity has an important effect on database performance.
You cannot view history information in this monitor. Instead, you can choose the following history functions:
- Reset + Since Reset
- Since Reset
- Since DB Start
You can view the information in graphical form by choosing Graphics (Top 30) to show the 30 tablespaces with the most activity, sorted in descending order for the chosen parameter (Reads, Block Reads, Blocks per Read and so on).
Structure
Entries marked “RAC only” appear only for Oracle Real Application Cluster (RAC).
- IO per File
This tab page displays current statistics on physical file accesses per data file:
Column |
Description |
File# |
File number |
Inst id RAC only |
Instance ID |
Full path |
Full file name including path |
Reads |
Number of reads |
Blk Reads |
Number of block reads |
Blk/Rd |
Number of blocks per read |
Rd Avg(ms) |
Read average time in milliseconds |
Rds/File(%) |
Percentage of reads per file |
Sgl Blk Rds |
Number of single block reads |
Sgl Blk Rds Avg(ms) |
Average time for single block reads in milliseconds |
Writes |
Number of writes |
Blk wrts |
Number of block writes |
Wrt Avg(ms) |
Average time for writes in milliseconds |
BBW |
Number of buffer busy waits |
Avg BBW(ms) |
Average buffer busy wait time in milliseconds |
BBW/File(%) |
Percentage of buffer busy waits per file |
· I/O per File With Total Lines – RAC only
This tab page displays the same information as in the table above plus Total lines for each Full path. This helps you identify a filesystem request problem that is not caused by a specific instance.
· Total per Device
This tab page displays current statistics on total physical file accesses per disk device. There are also entries for each file on the device.
Column |
Description |
File# |
File number |
Inst id RAC only |
Instance ID |
Name / Device |
Full file name including path |
Reads |
Number of reads |
Blk Rds |
Number of block reads |
Blk/Rd |
Number of blocks per read |
Rd Avg(ms) |
Read average time in milliseconds |
Rds/File(%) |
Percentage of reads per file |
% of Ttl Blk Rds |
Percentage of total block reads |
Sgl Blk Rds |
Number of single block reads |
Sgl Blk Rds Avg(ms) |
Average for single block reads in milliseconds |
Writes |
Number of writes |
Blk wrts |
Number of block writes |
Wrt Avg(ms) |
Average time for writes in milliseconds |
BBW |
Number of buffer busy waits |
Avg BBW(ms) |
Average buffer busy wait time in milliseconds |
BBW/File(%) |
Percentage of buffer busy waits per file |
· I/O per Path
This tab page displays current statistics about total physical file accesses per path.
Column |
Description |
Path |
File number |
Reads |
Number of reads |
Blk Rds |
Number of block reads |
Blk/Rd |
Number of blocks per read |
Rd Avg(ms) |
Read average time in milliseconds |
Rds/File(%) |
Percentage of reads per file |
% of Ttl Blk Rds |
Percentage of total block reads |
Sgl Blk Rds |
Number of single block reads |
Sgl Blk Rds Avg(ms) |
Average for single block reads in milliseconds |
Writes |
Number of writes |
Blk wrts |
Number of block writes |
Wrt Avg(ms) |
Average time for writes in milliseconds |
BBW |
Number of buffer busy waits |
Avg BBW(ms) |
Average buffer busy wait time in milliseconds |
BBW/File(%) |
Percentage of buffer busy waits per file |