Information Technology Reference
In-Depth Information
5.2
Stress Test of Data Read/Write and Data Center Backup
Writing and reading tests of large amounts of information are originating from
various database data centers. A total of four varying data sizes were tested, and the
average time of a single datum access was calculated for each.
(1)
Data centers A and B perform large amounts of information writing test through
Thrift Java. Five consecutive writing times among various data centers were
recorded for each data size. We substitute the results into Eq. (1) to calculate the
average time of a single datum write for each type of data center.
(2)
Data centers A and B perform large amounts of information reading test through
Thrift. Five consecutive reading times among various data centers were recorded
for each data size. We substitute the results into Eq. (1) to calculate the average
time of a single datum read for each type of data center.
The remote backup testing tool, Thrift Java, is mainly used to find out how long will
it take to backup each other's data remotely between data centers A and B. As a
matter of fact, tests show that the average time of a single datum access for the remote
backup of Apache HBase and Apache Cassandra only takes a fraction of mini-second.
Further investigations found that although the two data centers are located in different
network domains, they still belonged to the same campus network. The information
might have only passed through the campus network internally, but never reach the
internet outside, leading to speedy the remote backup. Nonetheless, we do not need to
setup new data centers elsewhere to conduct more detailed tests because we believe
that information exchange through internet will get the almost same results just like
performing the remote backup tests via intranet in campus. Five consecutive backup
times among various data centers were recorded for each data size. We substitute the
results into Eq. (1) to calculate the average time of a single datum backup for each
type of data center.
5.3
Cost-Performance Ratio Assessment
The following subsection will evaluate the performance index. We first substitute in
the average execution times into Eq. (2) to find the normalized performance index of
data centers for each test. Next we substitute the numbers into Eq. (3) to find average
normalized performance index. Finally, we substitute the numbers into Eq. (4) to find
the performance index of data centers as listed in Table 3. The total cost of ownership
(TCO) includes hardware costs, software costs, downtime costs, and operating
expenses. TCO over a five-year period is calculated using Eq. (5), and has listed in
Table 4. We estimate an annual unexpected downtime costing around USD$1000; the
monthly expenses includes around USD$200 machine room fees, installation and
setup fee of around USD$200/time, provisional changing fees of around
USD$10/time, and bandwidth costs. In Eq. (6) the formula assesses the cost-
performance ratio,
, of each data center according to total cost of
CP
jg
ownership,
PI
. Therefore we substitute the numbers
from Tables 3 and 4 into Eq. (6) to find the cost-performance ratio of each data center
as listed in Table 5.
, and performance index,
Cost
jg
j
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