EMC Vmax Architecture: Detailed Explanation

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Filed Under: Architecture,DMX\Vmax

Welcome back to my blog. After I started this blog,I am getting requests to publish a

post about Vmax architecture. Finally I am publishing this post about vmax architecture.

Note: Currently there are 3 types of EMC Vmax available EMC Vmax 10K, EMC Vmax

20K and EMC Vmax 40K.This article describing the general architecture of Vmax

models.

Symmetrix Vmax is EMC's prestigious product. Compared to the previous models,

Vmax has been optimized for increased availability, performance and capacity

utilization on all tiers with all RAID types. Vmax's enhanced device configuration and

replication operations results in easier, faster and more efficient management of large

virtual and physical environment.

The main architectural difference between DMX and Vmax model is that vmax has

engine concept. In DMX model, we have different hardware for front end(FA

director),back end(DA director) and memory modules. But in Vmax all these hardware’s

are integrated together and is known as Vmax Engine.

A EMC Vmax storage array support from 1 to maximum of 8 Vmax engines.

Each of these engines contains two symmetrix vmax directors. Each director includes

                  - 8 multi-core CPUs (total 16 per engine)

                  - Cache memory (global memory)

                  - Front end I/O modules 

                  - Back end I/O modules

                  - System Interface Module (SIB)

Apart from this, each engine has redundant power supplies, cooling fans, standby power

supplies (SPS) and environmental modules.

All these engines are interconnected using Vmax Matrix Interface Board Enclosure

(MIBE).Each director has two connections to MIBE via system interface module

(SIB) ports as shown below.

Multi-core CPUs:

Multi-Core CPUs deliver new levels of performance and functionality in a smaller

footprint with reduced power and cooling requirements. Each director has 8 multi core

CPUs and a total of 16 CPUs per engine.

Cache memory(global memory):

Each director can be configured with 16, 32 or 64 GB of physical memory. Of this, a

small portion (4 GB) is reserved for local processing, and the rest constitutes Global

Memory. Global Memory on any given director is always mirrored to another director in

the system. So the minimum usable memory will be 16 GB(total 32GB, on a single

engine configuration) and maximum will be 512GB (total 1024GB,fully loaded eight

VMAX Engines system)

Memory is accessible by any director within the system:

◆ If a system has a single VMAX Engine, physical memory mirrors are internal to the

enclosure.

◆ If a system has multiple VMAX Engines, physical memory mirrors are

provided between enclosures.

Front End I/O Module:

Front end modules are used for host connectivity. Host connectivity via Fibre Channel,

iSCSI and FICON are supported.

Back End I/O Module:

Back end module provide access to the disk drives. Disks drives are configured under

these I/O modules.

System Interface Module (SIB):

SIBs are responsible for interconnecting the Vmax engine's directors through  Matrix

Interface Board Enclosure(MIBE).Each Vmax engine has two SIBs and each has two

ports.

Similar to DMX3 and DMX4 arrays, Vmax has two types of bays

 1. System bay:

System bay contains all Vmax engines. Apart from Vmax engines, it contains system

bay standby power supplies (SPS), Uninterrupted Power Supply (UPS), Matrix Interface

Board Enclosure (MIBE), and a Server (Service Processor) with Keyboard- Video-

Mouse (KVM) assembly.

 2. Storage bay:

The Symmetrix V-Max array Storage Bay is similar to the Storage Bay of the DMX-3 and

DMX-4 systems. It consists of eight to sixteen Drive Enclosures, 48 to 240 drives, eight

(8) SPS modules, and unique cabling when compared with the DMX Series. The

Symmetrix V-Max array Storage Bay is configured with capacities of up to 120 disk

drives for a half populated bay or 240 disk drives for a fully populated bay. Drives, LCCs,

power supplies, and blower modules are fully redundant and hot swappable and are

enclosed inside Disk Array Enclosure (DAE).One DAE holds 15 physical disk drives and

one storage bay has total 16 DAEs (hence a storage bay has maximum of 240 disk,

16*15)

Vmax Engine Front View :

Below is a Vmax engine front view. As described above, Vmax engines are located in

Vmax system bay. We can see the power supplies located at two sides and cooling fan

module located in middle.

Vmax Engine Rear View:

This example displays the rear view of the V-Max Engine.

As explained earlier each V-Max Engine contains two director boards named here

as Odd and Even director, four Front End I/O Modules, four Back End I/O Modules and

two System Interface Boards (SIB). The Back End I/O Modules are numbered as Module

0 and Module 1. The System Interface Boards are named as Modules 2 and 3. The

Front End I/O Modules are numbered as Module 4 and Module 5.

The top director board combined with the left Front End I/O Modules 4 and 5 represents

the even numbered director. The bottom director board combined with the right Front

End I/O Modules 4 and 5 represents the odd numbered director. For example, if this is

engine 4 the top director would be director number 8 and the bottom director would be

director number 7.

Vmax Engine Port Assignment:

This is a typical Vmax port assignment diagram

Above diagram contains port assignment of System Interface Board, the Back End I/O

Modules, and the Front End I/O Modules.

 As I explained earlier Vmax engines are interconnected using MIBE using System

Interface Board ports Port A and Port B. using these ports all directors communicate

through the Virtual Matrix via redundant connections.

Each director within a V-Max Engine contains two Back End I/O Modules. Each Back End

I/O Module has a single port, which holds a single Quad Small Form-Factor

Pluggable (QSFP) connector. The QSFP connector cable contains 4 smaller cables,

each have a connection to four Drive Enclosures, providing Back End Fibre

Channel connectivity to the disk drives. On Back End I/O Module 0 these connections

are designated as A0, A1, B0, and B1. On Back End I/O Module 1, these connections

are designated as C0, C1, D0, and D1.

Each director also contains two Front End I/O Modules. The port designations on the

Front End I/O Module will vary based on the interface type. This example represents

four Fibre Channel Front End I/O Modules. In this, configuration module 4 will contain

ports E0, E1, F0, and F1. Module 5 will contain ports G0, G1, H0, and H1.

As we discussed previously, the left two Front End I/O Modules are connected to the

even numbered director. If it is Engine 4(director number associated with engine 4 is

director 7 and 8), then the first port on the left most module 4 would be director 8 port

E0. This is a significant departure from other Symmetrix systems and is results of the

overall increased port count in the Symmetrix V-Max array.

Vmax Engine Configuration with Storage Bays:

Now let’s have a look at how the vmax engine configures along with storage bay. I am

giving pictorial representation, from one vmax engine to 8 vmax engine configuration

along with storage bays. This is the standard EMC recommended configuration layout.

1. One Vmax engine with storage bay: 

The Symmetrix V-Max array requires at least one V-Max Engine in the System Bay. As

shown, the first engine in the System Bay will always be Engine 4 as counted

starting at 1 from the bottom of the System Bay. In this example, Engine 4 has

two half populated Storage Bays. One bay is directly attached and the second is a

daisy chain attached Storage Bay. This allows for a total of 240 drives. To populate

the upper half of these Storage Bays with drives you will need to add another V-Max

Engine.

2. Two Vmax engine with storage bay: 

In this example, the system has been expanded to include Engine 5. This allows the top

half of both Storage Bays to be populated with drives. This represents the correct order

for adding V-Max Engines to the System Bay. V-Max Engines are added from the middle,

starting with 4, then 5, then 3.

3. Three Vmax engine with storage bay: 

Again, working from the middle out the system has been expanded. The next V-Max

Engine is 3, allowing the attachment of two additional Storage Bays. This allows for a

total of 720 drives.

4. Four Vmax engine with storage bay: 

5. Five Vmax engine with storage bay: 

6. Six Vmax engine with storage bay: 

7. Seven Vmax engine with storage bay: 

8. Eight Vmax engine with storage bay: (Fully populated)

Now that we have the general idea, let’s take a look at how a system gets fully

populated. Still working from the inside, out alternating above and below Engine 4, each

engine is added until the System Bay is fully populated with 8 V-Max Engines. As more

engines are added the corresponding Storage Bays are added. In this example, the

color coding indicates the relationship between the engines and their associated

Storage Bays. Fully populated, this configuration allows for a total of 2,400. You will

notice that Engines 1, 2, 7, and 8 each manage two daisy chain attached Storage Bays.

This represents a supported system implementation, not a design limitation.

 I tried to cover is; only the EMC Vmax architectural part in this post, not all Vmax

features. I will be writing more post related to Vmax features later. Hope now you got

an idea about Vmax architecture