In this article, we estimate controller’s performance of midrange storage system NetApp FAS8040 for different workload profiles, as well as other parameters of IOPS per GHz, IOPS per GB.

All the performed calculations are based on the methodology described in the article «Methodology of IOPS Estimation».

Let’s gather all necessary information needed for a calculation.

- The frequency of processor cores – 2,1 GHz.
- The number of cores on one controller – 8.
- The number of processors on one controller – 1.
- The sum frequency calculation – 2,1x8x1 GHz = 16,8 GHz.
- At this stage we can get a rough estimation of IOPS for one controller. To do this, it is necessary to use the relation between the number of IOPS and sum frequency of the controller. This value is specified in the methodology (10000 IOPS / GHz). Multiply 16,8 GHz x 10,000 IOPS / GHz, we obtain a rough estimation 168000 IOPS per controller. Thus, the performance of a pair of controllers is equal to 336000 IOPS. We can use these rough estimates for self-examination.
- We take information about recommended configurations of RAID groups in « FAS8xxx Best Practice Guide »:
- RAID-DP SSD are used in the configuration 14+2.
- RAID-DP SAS are used in the configuration 14+2.

- Max disk drive quantity for one pair of controllers is 720.

In the article «NetApp FAS8xxx : a Brief Overview» it’s noted that 131 Flash disks of 400GB can be installed in the system FAS8040. However the max quantity of Flash drives for All-Flash configuration, defined on the level of software, is 240.

For the calculation we will use 128 Flash disks in the configuration RAID-DP 14+2 in accordance with the recommendation of NetApp.

**The estimation for max IOPS (Cache Read Miss)**

Let’s set the values for the estimation:

- Read operations – 99%.
- The configuration for RAID groups of Flash drives – RAID-DP 14+2.
- The quantity of RAID groups for Flash drives – 8.
- The configuration for RAID groups of SAS 10K drives – RAID-DP 14+2.
- The quantity of RAID groups for SAS 10K drives – 35.
- We will use one disk group RAID-DP 6+2 for rest SAS disks.

The graphic representation results of calculation:

Max IOPS for one HA-pair is **507810**.

Max IOPS for one controller is **253905**.

The ratio of IOPS per GHz is **15113**.

The ratio of IOPS per GB is **1,16**.

Real Flash storage capacity is about 39 TB.

Real SAS 10K storage capacity is about 389 TB.

Let’s compare this result with a rough estimation, which we did in the beginning of this article. Then we got 168000 IOPS for one controller. The difference from the new result is about **34**%.

The difference with the new result is 85905 IOPS. This is bigger that 50% of the rough estimation. This suggests that the ratio of IOPS per GHz for the system is higher than the ratio – 10000 IOPS per GHz, which we used in the calculation.

**The IOPS estimation for DB like workload (Cache Read Miss)**

The Initial parameters are the same, but the percentage of read operations is different. A typical ratio between read and write operations is equal to 70/30 for databases (OLTP workload).

The graphic representation results of calculation:

Max IOPS for one HA-pair (DB like) is **213280**.

Max IOPS for one controller (DB like) is **106640**.

The ratio of IOPS per GHz is **6348**.

The ratio of IOPS per GB is **0,49**.

The real capacity of disk space on Flash and SAS drives is the same.

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