Performance and Sizing
33
Sizing the Enterprise Backup Solution
Speed Tests
Determining the speed of Backup and Restore processes in a real-world environment is the most
important factor in designing and implementing the Compaq StorageWorks EBS. Fibre Channel
is designed to produce a theoretical maximum of 1.0625 Gigabits per hour. This equates to
100 Megabytes per second or 360 Gigabytes per hour. (Test results are expressed in GB/H for
clarity).
IMPORTANT: A single DLT 7000 drive is rated at a theoretical maximum of 18 GB/H.
To determine the approximate speed of backup and restore jobs in an EBS environment,
Compaq began testing non-compressible (1:1) data.
IMPORTANT: Compaq tested both the Seagate Backup Exec and Computer Associates (CA)
ARCserveIT in an EBS environment to benchmark the DLT performance. Both Seagate and CA
generated consistent throughput of approximately 15 GB/H.
Tests were performed with each job configured to write to a single DLT drive. Tests show near-
linear scalability. The TL895 supports seven DLT 7000 tape drives.
1:1 Backup & Restore
0
14.87
29.93
44.77
59.70
74.25
89.49
109.16
0
14.76
29.97
44.88
58.14
69.87
80.36
90.15
0
20
40
60
80
100
120
1
2
3
4
5
6
7
Number of DLT Drives
Gigabytes Per Hour
Backup
Restore
Figure 4-1. Test Results of Backup and Restore Jobs.
Compression Tests
IMPORTANT: The amount of compression has a direct impact on the rate that a DLT 7000 tape
drive can write data
.
T
ests showed the number of DLT drives and compression scaled near 1:1, but the total rate of
combined throughput declined slightly as compression increased. It was also determined that the
maximum throughput on a single DLT drive was 43 GB/H.