TESING INFORMIX RESTORES WITH ONBAR
Steps to find where the slow-down is (backup):
Run each of the 3 tests a few times so you can gain an average time. Your
results should look like the following:
- Reduce the restore process to managable size which still exposes
the throughput problem. Use the same dbspace set the you used in the
- Ideally you would want to initally test restoring BAR_MAX_BACKUP
number of dbspaces.
- Time an initial restore to act as a baseline for future timings. When
performing these timings be sure to time only the physical restore (not the
logical resore). We are only working on data transfer throughput at this point.
Use the BAR_ACT_LOG to find the time at which physical restore began and ended.
- Using the Disk Writer program we will
measure the speed in which the OS can write
the disk(s) associated with the dbspace which is being tested.
Remember to use the same block size that informix uses (8 *
- Using the XBSAReader Utility, Measure
how fast the storage manager can send data to ON-Bar through the XBSA interface.
REGULAR restore XBSAReader
tabdbs1 tabdbs2 tabdbs3 tabdbs1 tabdbs2 tabdbs3
Time#1 85 87 85 84 88 91
Time#2 85 86 85 84 88 88
Time#3 91 92 92 91 84 85
tabdbs1 tabdbs2 tabdbs3
Time#1 42 42 42
Time#2 42 42 42
Time#3 42 42 42
From the results above (taken from a sample test) you can see that
the bottleneck lies in the Storage manager. The Storage manager can only
send ON-Bar data at a rate of approximately 87 secs per dbspace. While
the OS can write data to the chunks at a rate of 42 secs per dbspace.
Informix's speed is usually with in 10-15% of the Diskwriter speeds (assuming
you are restoring an archive which was taken while the engine was under very
If we had found that the XBSAreader was as fast as the diskreader and the regular
restore time were the same then we would conclude that the Informix/ON-Bar peice
is the bottleneck.
If we found that the average time for the diskreader was (lets say) 150 secs per
dbspace and so was the resgular restore time, Then we would conclude that the
bottleneck lies with the disk I/O system.