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IOPS Estimation for EMC VNX5600

Written on:July 11, 2015
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In this article, we estimate the performance of the storage system controllers of the new EMC VNX5600 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 the calculation.

  • The frequency of processor cores – 2,4 GHz.
  • The number of cores on one controller – 4.
  • The sum frequency calculation – 4×2,4 GHz = 9,6 GHz.
  • At this stage we can get a rough upper 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). Let’s multiply 12 GHz x 10000 IOPS / GHz, we obtain a rough estimation 96000 IOPS per controller. Thus, the performance of a pair of controllers is equal to 192000 IOPS. We can use these rough estimates for self-examination.
  • We take information about recommended configurations of RAID groups in «View on new EMC VNX2 series»:
    • RAID 5 SSD are used in the configuration 4+1 or 8+1.
    • RAID 5 SAS are used in the configuration 4+1 or 8+1.
  • Max disk drive quantity for VNX5600 is 500.

Now we need to estimate the maximum number of Flash drives, which will be aligned with the performance of controllers.

In the article «View on new EMC VNX2 series», we mentioned that VNX5600 and VNX5800 systems have the same number of SAS chips, so in theory, VNX5600 system can be used the same number of Flash drives, as in VNX5800.

However, we know that the processors, which are used in VNX5600, are weaker. Therefore, we need to use the ratio between total frequencies of controllers VNX5600 and VNX5800, so that we could correctly estimate the number of Flash disks in VNX5600.

We know an estimation of Flash drives quantity for VNX5800, it is equal to 82 Flash drives (see Article «IOPS Estimation for EMC VNX5800»).

The ratio between the total frequency of controllers is 9,6/12 = 0,8.

The estimation of Flash drives number for VNX5600 is equal to 82*0.8 ~ 66 Flash drives.

Also we have to consider that VNX5800 has 6-core CPUs and VNX5600 has 4-core CPUs (they have some difference between cache and architecture of CPU). So we suppose that for more real estimation we have to use 60 Flash drives.

The use of two types of Flash drives (SLC and MLC) in VNX2 is possible, so we will make two configurations:

  • SLC drives 200GB for FastCache (max 20) and MLC drives 800GB
  • MLC drives 800GB.

The estimation for max IOPS (Cache Read Miss)

Let’s set the basic values for the estimation:

  • Read operations – 99%.
  • The configuration for Fast Cache (SLC) – RAID10 1+1.
  • The quantity of groups – 10.
  • The configuration for MLC drives – RAID5 4+1 or 8+1.
  • The configuration for SAS 10K – RAID5 4+1 or 8+1.

As a result we have got such a calculation:

04272015_VNX5600_R99_IOPS

The graphic representation results of calculation:

04272015_VNX5600_R99_IOPS_graph

Total:

Max IOPS is 265777.
Max IOPS for one controller is about 132889.
The ratio IOPS/GHz is about 13843.
The ratio IOPS/GB is 0,864.

Real Flash storage capacity is about 34 TB.
Real SAS 10K storage capacity is 267 TB.

Let’s compare this result with a rough estimation, which we did in the beginning of this article. Then we got 96000 IOPS for one controller. The difference with the new result is about 28%.

An estimation with Fast Cache:

04272015_VNX5600_R99_IOPS_FC

The graphic representation results of calculation:

04272015_VNX5600_R99_IOPS_FC_graph

Total:

Max IOPS is 267122.
Max IOPS for one controller is about 133561.
The ratio IOPS/GHz is 13913.
The ratio IOPS/GB is 0,896.

Real Fast Cache capacity is 1787 GB
Real Flash storage capacity is about 22 TB.
Real SAS 10K storage capacity is about 267 TB.

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

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

04272015_VNX5600_R70_IOPS

The graphic representation results of calculation:

04272015_VNX5600_R70_IOPS_graph

Total:

Max IOPS (DB like) is 144079.
Max IOPS for one controller (DB like) is about 72040.
The ratio IOPS per GHz is about 7504.
The ratio IOPS per GB is 0,468.

An estimation with Fast Cache:

04272015_VNX5600_R70_IOPS_FC

The graphic representation results of calculation:

04272015_VNX5600_R70_IOPS_FC_graph

Total:

Max IOPS (DB like) is 161083.
Max IOPS for one controller (DB like) is 80542.
The ratio IOPS per GHz is 8390.
The ratio IOPS per GB is 0,541.

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