ABC.com is running four applications (A, B, C, and D) daily as follows: “A” has its consistent peak
workload of 65K IOPS with an average 4KB blocksize for 4 hours from 9am. “B” has its consistent
peak workload of 20K IOPS with an average 8KB blocksize for 3 hours from 8am. “C” has its
consistent peak workload of 50K IOPS with an average 4KB blocksize for 4 hours from 10am. “D”
has its consistent peak workload of 10K IOPS with an average 8KB blocksize for 2 hours from
11am. From a performance viewpoint, what is the minimum number of 2Gbit array ports into a
single array would you suggest to handle both this workload and 25% growth?
A.
5
B.
3
C.
6
D.
4
Explanation:
For required throughput, multiple IOPS by blocksize , and aggregate all together, as they all
overlap at 11 a.m.
IOPS = I/O per second
1K KB = 1000 KB = 1 MB
1 Gb / s ? 100 MB/s
N = Number of HBAs ; each which support 2Gb/ s (? 200 MB/s)
A- 65 K IOPS x 4 KB = 260K KB /sB- 20 K IOPS x 8 KB = 160K KB /s
C- 50 K IOPS x 4 KB = 200K KB /s
D- 10 K IOPS x 8 KB = 80K KB /s
700K KB /s
Add 25% for growth + 175K KB /s
875K KB / s = 875 MB /s N = 875 MB/s 200 MB/s = 4.375
Rounding up, will need 5 HBAs at minimum to support the peak workload and allow for 25%
growth.