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June 2nd, 2016 05:00

# How to calculate disk work load?

Can someone tell me the calculation, how to calculate?

An application created 4500 I/Os at peak workload with a peak work loads with read/write ratio of 2:1. What is disk load at peak activity for a RAID 6 configuration?

633 Posts

June 9th, 2016 07:00

Hi Arslan,

I ran your question by Sagar Patil, who manages the ISM curriculum. Here is his answer:

Can someone tell me the calculation, how to calculate?

An application created 4500 I/Os at peak workload with a peak work loads with read/write ratio of 2:1. What is disk load at peak activity for a RAID 6 configuration?

Therefore, reads = 2/3 * 4500 = 3000 I/Os

And writes = 1/3 * 4500 = 1500 I/Os

For RAID 6, write penalty is 6.

Therefore, Disk load = (3000 * 1) + (1500 *6) = 3000 + 9000 = 12000 I/Os

633 Posts

June 3rd, 2016 06:00

Hi Arslan,

Can you show how you are currently calculating the answer to this question?

34 Posts

June 4th, 2016 00:00

Hi Kate,

34 Posts

June 5th, 2016 00:00

Sorry for above calculation, as i did not calculate with 4500

66.66% reads of 4500 = 2997

33.33% Writes of 4500 = 1499.8

34 Posts

June 5th, 2016 00:00

Hy kate,

I found the solution and formula is "read+(write*write penalty)".

So above calculation will be

reads are 66.66% and writes are 33.33%

RAID 6 penalty is 6

Hence  66.66 + (6*33.33) = 66.66 + 199.98