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BP1021 Microsoft SQL Server 2008 Backup and Restore using Dell EqualLogic 19
Impact of transaction logs backup
Figure 17 illustrates the increase in CPU utilization during every transaction log backup. This increase
appears as a spike in utilization for each of the transaction log backups. The impact to application and
disk response times were minimal compared to the impact during full backup and are not shown.
Figure 17 Impact on CPU utilization during transaction log backup
Backup duration and Throughput
The total time required to complete full database and transactional log backups was measured along
with throughput during each operation. The baseline full backup in Figure 18 is from the baseline test
configuration 2c (i.e. three target volumes with two backup files each) from Figure 7. Figure 18 shows a
slight increase in backup time for the backups taken during the user load versus the backup taken with
no user load. It also shows the decrease in write throughput of full backup taken with user load
compared to the baseline full backup with no user load.
Figure 18 Backup duration and throughput comparisons
As seen in Figure 18, user transactions caused a decrease in write throughput and increase in backup
time slightly. However, as shown in previous sections, the impact on server CPU utilization, transaction
response times, and transaction I/O latency were much higher during the full backup.