Dell Compellent Series 40 - Manual (Page 15)

Cost and Performance benefits of Dell™ Compellent™ Automated Tiered Storage for Oracle® OLAP
Workloads
15
Disk Space Consumed Tier wise distribution
Figure 11.
In the Figure 11, we observed that after introducing tiers and enabling Data Progression based on the
parameters outlined in the storage profile that infrequently accessed blocks of data are moved to a
lower storage tier and RAID level, or to a different RAID level within the same tier. Whether data is
moved to a new tier or RAID level, the migration frees up space on the higher tier or RAID level.
After the Data Progression cycle on the tiered storage, the total disk space consumed was around 1.35
TB against 1.85 TB of the baseline configuration. The disk space consumed in the baseline test (1.85
TB) was on Tier 1 storage only where as in the tiered configuration it was observed that 1.35 TB of disk
space is automatically distributed across different storage tiers (0.25 TB on Tier 1, 0.43 TB on Tier 2,
0.67 TB on Tier 3), which helped to save 70 percent disk space in the high cost tier1 storage.
This is due to the movement of infrequent accessed data to Tier 2 and Tier 3 storage space based on
the storage profile defined by means of IO characteristics of the database volumes.
Summary
Table 3 shows the overall summary of all test cases in terms of performance, cost, and disk space
usage across different tiers.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Baseline Test Replay Enabled After Data
Progression optimized
Disk
S
p
ac
e
Co
n
sum
ed(
T
B)
Disk Space Consumed
Tier3(7.2K SAS)
Tier2(10K SAS)
Tier1(15K SAS)