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E20-324 VideoILT material questions - Performance Drives
Hi,
Please help me with the following questions. Thank you and your help is much appreciated.
I have questions on Module 4, at the bottom of page 28:
" Total performance drives Total Approximate Drives = RAID Group IOPS / (Hard Drive Type IOPS) + Large Random I/O adjustment
+ Hot Spares + System Drives
For example, if an application was previously calculated to execute 4,000 IOPS, the I/O is 16 KB random requests, and the hard drives specified for the group are 15K RPM SAS drives (see Table 9 Small block random I/O performance by drive type):
Total Approximate Drives = 4,000 / 180 + 0 + ((4,000 / 180) / 30) + 5
Total Approximate Drives = 28 "
From the formula above:
Raid Group IOPS / ( Hard Drive Type IOPS 0 = 4,000/180
Q1 . Large Random I/O adjustment = 0 (is this right ?)
Q2. What is ((4,000 / 180) / 30) ? Why is (4000/180) divided by 30 ? What is 30 ?
Q3. What is 5 ?
Q4 .How many system or vault drives is required ? 4 ?
Q5. Is Raid 10 always configured for vault drives ?
Q6. In the earlier part of the page : " Do not include the system drives and hot spare drives into the performance calculation when calculating the operational performance "
Why is the hot spares and system drives included in the above formula ?
andre_rossouw
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June 13th, 2013 07:00
Answer posted to your later question.
RRR
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June 25th, 2013 05:00
For those who are interested: https://community.emc.com/message/738340#738340