Details Explanation Of SAN Storage Architecture

Details Explanation Of SAN Storage Architecture

This blog explains What is SAN storage how SAN storage works. What are the SAN Storage components and how they connects to each other.

What is SAN Storage ?

SAN storage stands for Storage Area Network. A SAN is a specialized high‐speed network of storage devices and SAN switches connected to computer systems called as Host or Server via Fiber optic cables. Host uses the storage from storage arrays as if its local to Host. As the data communication happens via fiber optics the data speed is high in comparison to NAS storage.

Components Of SAN Storage 

SAN Components can be divided into 3 layer. Host, Fabric and Storage Layer. These three layers connects to each other and form an Storage Area Network or SAN network. Each layer has its own functions. We will discuss about their function in coming section.

Below is a very simple architecture diagram of SAN storage which has all of Storage Area Network.

                           

Host Layer Of SAN Storage

Host layer of SAN Storage has servers or host. Hosts are basically a hardware having its own resources like CPU, Memory, Disk storage and an Operating system running on it. Along with these it has also dual HBA card which connects to the Fabric Layer of SAN Network.

What is Fabric In SAN Storage

Fabric layer or a Fabric of SAN storage consist of one or more SAN switch. SAN Switch provides a connections points in SAN architecture. All Host connects to SAN switch and Storage Array also connects to same SAN switch. Thus it act as mediator between Host and Storage.

Typical SAN network has two fabric for high redundancy. In case if one Fabric goes down then other fabric takes care of the data flows in storage area network.

Storage Layer in Storage Area Network

In storage layer of Storage Area Network storage arrays are present where data resides in physical disks. Storage Array consist of physical disk. These disks are grouped logically using special technology called RAID for data protection. These RAID helps in data recovery whenever a disk failure occurs. There various types of RAID type. Depending on requirement specific RAID type is selected for creating raid group. Common RAID type are RAID 5 and RAID 6.

Most of storage arrays has Dual storage processors (SPs) which are the front end of the storage array. These SP has front end IO module which has FC ports. These FC ports connects to SAN switch via FC cables.

Below is an architecture diagram of typical SAN storage which has all components of Storage Area Network with redundant setup.

How SAN Storage Works 

When a host from a host layer wants to access a storage device on the SAN, it sends out a block‐based access request for the storage device. SCSI commands are encapsulated into FC packets. Then the Host HBA transmits the FC request to the Storage layer via Fabric.

From Fabric layer SAN Switch then sends this request to Storage Array. In Storage Array SP receives the request, process it and then sends an acknowledgement back to the host through same path.

For more detail explanation on this topic please watch this YouTube Video. For more such videos on SAN and NAS technology Subscribe to the channel.

             

What Is And How NPV Works SAN Switch

What Is And How NPV Works SAN Switch

In this blog we will discuss what is NPV and how NPV works in SAN switch. NPV sounds similar to NPIV but they are different in terms of their use. Click the link to check what is NPIV and how NPIV works in SAN switch. For all tutorial under SAN switch click here.

What Is NPV In SAN Switch

What is NPV In SAN Switch ? NPV stands for N_Port Virtualization. This is SAN Switch level features. NPV enabled switch act as a proxy switch and bypass all FC services request to its up-link switch. NPV is a Cisco Specific term other vendor calls it as different name. In terms of Brocade its called as Access Gateway Switch.

How NPV Works In SAN Switch

In order to understand how NPV works we should understand what happens when a new switch connects to fabric. In usual case when a SAN switch is connected to a fabric its gets Domain ID and participate in Fabric Services like assigning FCID to initiator.

Now in case of NPV if the SAN switch is NPV enabled then it will not have any Domain ID and does not participate any FC services. Whatever Device connected to NPV enabled switch such as host , switch or UCS or any device gets FC services from its up-link switch.

Use Of NPV SAN Switch Network

There are various ways to use NPV in SAN switch. Below are some examples where we can use NPV. One of the rare use of NPV where fabric requires more then 239 switches or there is a limitation of Domain ID. For each switch in a fabric it requires a domain ID. Now as the fabric grows number of SAN switch also grows and as a result Domain ID also grows. If the number of switches reaches to 239 domain id also reaches to 239. In such scenario if more switches requires then NPV is a solution to add more switches to fabric.

Another practical use of NPV is multi vendor SAN switches in same fabric. If you have a SAN fabric with switches of multiple vendor then NPV is necessary. For example you can connect a Cisco Core switch with brocade SAN switch. Note both switches must be interoperability mode.

You can also use NPV for migrating SAN switches from one vendor to another. We can use NPV as pre deployment stage for SAN switch migration from one vendor switch to another. For more details you can visit the below link.

Below is an YouTube videos which have details explanation of NPV features and its uses. Subscribe the channel for more such videos on SAN switch training.


       

What Is And How NPIV Works In SAN Switch

What is NPIV In SAN Switch

NPIV is SAN switch port level virtualization feature. NPIV stands for N-Port ID Virtualization. NPIV allows multiple initiator to logged in to same single physical target port. NPIV is mostly used SAN network where ESX Host, Blade Server and UCS deployment are present.

How NPIV Works In SAN Switch

In order to understand how NPIV works in SAN switch first lets understand how a SAN connectivity works without NPIV. In usual case one initiator or host is connected to single port of SAN switch.
During FLOGI process the switch assign a FCID to initiator and the initiator is logged in to switch port.

Below is one diagram which has simple connectivity of two server to SAN switch. where two server use two ports of SAN switch to logged in.

Now in case of NPIV multiple initiator tries to login to same single physical port of SAN switch. If SAN switch port is NPIV enabled then switch port accepts request from each initiator and assign a FCID to each initiator. Once all initiator receives a FCID all of them are logged to to same physical port.

Below diagram explains the connectivity and uses of NPIV in SAN switch network. Here compute system which is similar to blade server of ESX host which has single physical HBA which connects to single SAN switch port. In back-end the compute system has multiple nodes which shares same common physical HBA. Each node of compute system has a virtual HBA having virtual WWPN.

During FLOGI Process each virtual WWPN send request to same SAN switch port and if the SAN switch port is NPIV enabled it accepts all request and assign FCID to each node or initiator. This way multiple initiator logged in same SAN switch port.

Where We Use NPIV In SAN switch

There are various uses of NPIV in SAN network but below are most common use of NPIV.
If your environment has ESX, UCS, or Blade Server Deployment then definitely your SAN switch ports are NPIV enabled.

Second common use of NPIV is that it allows masking of LUN to individuals VMs. It means if you have multiple VMs in ESX host then you can do zoning between the VMs WWPN and Storage array. Then you can share individual LUNs to particular VM.

Third common use is that it reduce messy cable connectivity of SAN network. If you have large number of server then lot of cable connection is require between server and switch which makes difficult for Data Center admin to perform physical maintenance activity. As NPIV reduce the number of connection between server and switch physical management of Data center make simpler.
Below is one of the videos which explains the purpose of NPIV and how it works. Subscribe to YouTube Channel for such videos.      

                         

What is FLOGI PLOGI and PRLI In SAN Switch

What is FLOGI PLOGI and PRLI In SAN Switch

What is FLOGI PLOGI and PRLI In SAN Switch read this blog and you will get the answer. This blog has detail explanation of three device login process on SAN switch. Basically there are three device login process FLOGI, PLOGI and PRLI.

What is Device Login In SAN Switch ?

Device Login is a series of process which happens when a new node or devices is connected to a Fabric. Once Device Login Process Completes then a device can communicate with other devices in same fabric. Its Involves three steps FLOGI PLOGI and PRLI.

Components of Device Login In SAN Switch

Host – These are the server which are connected to Switch.
Array – These are the storage Array connected to Switch
SAN Switch – A SAN switch having FC Ports

Not only above three devices any other device which connects to SAN switch with FC protocol has to go through device login process..

What is FLOGI Process in SAN switch network

FLOGI Process happens when a new device is connected to switch or fabric for the first time. Once the device is power the device sends it first frame to the switch where it is connected. The first frame contains some information like WWPN and buffer to buffer credits (B2B credits).

The switch reads these information and then assign a 24 bit Unique ID address to device. This unique ID called as FCID. Switch uses this FCID to identify the end device connected to it in SAN network. Then the end device also confirms to the switch that it received FCID.

What is PLOGI SAN Switch Network.

Port initialization in PLOGI Process in SAN Switch

PLOGI Process has two port initialization and registration in Name Server. During port initialization information like port type and port speed are exchanged between end device or host and SAN switch. SAN switch use these information and negotiate with host. During negotiation SAN switch will come to know whether the end device is a server or a storage by referencing the port type.

What is Name Server In SAN Switch Network

During Name Server registration of PLOGI process the device register its information in Name server. This provides information to device about all other device which are registered in name server that it can communicate to.

Each fabric is SAN switch network maintains a name server. These name server contains the information of every devices connected to the SAN Fabric. Two device in SAN switch network can communicate only if both of them are Name server.

What is PRLI Process Login In SAN Switch

PRLI also stands for process Login. During this process actual communication happens between device connected to switch which are present in Name Server. In simple terms we can say that a during PRLI N_port communicates with another N_Port. In broad term a host communicates with storage array.

During PRLI process a host sends a PRLI request to storage array. If proper zoning and LUN masking is exists then storage array accept the PRLI request and start a communication between them.

Device Login Process SAN Switch With Diagram

Below is a diagram which explains step by step process of Device login in SAN switch network. Subscribe the blog for more such article.

Video Tutorial On Device Login Process SAN Switch

Watch the below videos tutorial from YouTube explaining the device login process in SAN switch. Subscribe the channel for more such videos.


            

Zoning In Brocade SAN Switch

Zoning In Brocade SAN Switch

Zoning In Brocade SAN Switch. We will discuss about zoning in brocade switch in details.Zoning is necessary to provide a secure path for SAN Host to access Storage Array. We will discuss how we can do zoning in brocade switch via command line.

Zoning in Brocade SAN Switch

Important Terms Brocade SAN Switch Zoning

Lets first some important terms on Brocade SAN switch zoning which is useful to understand the process
of zoning in brocade SAN switch.

What is WWPN in Brocade SAN Switch Zoning

WWPN stands for World Wide Port Name. Each port in SAN network has a unique WWPN. In SAN network port are identified by its WWPN. A WWPN is 64 bit address. Below is an example of WWPN
Ex : 10:xx:xx:xx:xx:xx:xx:xx

What is Alias Name In Brocade SAN Switch

Alias Name In Brocade SAN Switch are Human readable name of WWPN. As WWPN are 64 bit address and difficult to remember. SAN Switch admin provide a name for WWPN for easy reference.

What is Zone Brocade SAN Switch

Zone in Brocade SAN Switch are nothing but Group of alias member. These member are alias of Host WWPN and Storage Array WWPN.

Active Zone Configuration SAN Switch

Active Zone Configuration SAN Switch consists of Group of Zones in Active State. In a fabric only one Zone config can be in active state and the zones present inside it are effective zones.

What we need before Zoning Brocade SAN switch

Below are some of the information we need before we start ding zoning in Brocade switch

SSH Or GUI connectivity to Brocade SAN switch
Server Name For Zoning
Two WWPN  of Server HBA Port- Connected to each Fabric
Ex : Host1: 10:xx:xx:xx:xx:xx:xx:xx
WWPN of Front End Storage Array Port Connected to Fabric
Ex: Array_Port1 : 50:xx:xx:xx:xx:xx:xx:xx:xx

Steps Of Zoning in Brocade SAN Switch

Once we have the above information. Below are the steps we need to perform. These are overall steps of zoning in brocade switch In next section we will see the CLI commands for zoning.

1.Check Connectivity of HBA Port To Fabric.
2.Create Alias Name For HBA Port WWPN and Storage Array Port WWPN.
3.Create a ZONE and add alias member in it.
4.Add the zone to active configuration zone
5.Save the active configuration zone
6.Enable active configuration zone

In some SAN network some additional feature are enabled for more security. Based on that the zoning may include more steps

CLI Command for Zoning in Brocade SAN Switch

CLI Command for Zoning in Brocade SAN Switch are executed by login to SSH or via Putty session on Switch. Below are the CLI commands of Brocade SAN switch zoning.

1.Check Connectivity of HBA Port To Fabric.
nodefind 10:xx:xx:xx:xx:xx:xx:xx
2.Create Alias Name For HBA Port WWPN and Storage Array Port WWPN.
alicreate “host1_hba1”,”10:xx:xx:xx:xx:xx:xx:xx”
3.Create a ZONE and add alias member in it.
zonecreate “zone1”, “host1_hba1; Array_Port1 ”
4.Add the zone to active configuration zone
First we need to find out which zone config in in active state using command.
cfgactvshow | more
cfgadd "activecfg1",“zone1”
5.Save the active configuration zone
cfgsave
6.Enable active configuration zone
cfgenable "activecfg1“

Today’s Question on Zoning In Brocade SAN Switch

Now a tricky question for you guys. Do research and let me know your answer in comment section.

What is the purpose of cfgsave command ?
What will happen if cfgsave command is not executed ?

Below is video on SAN switch zoning. Watch it Like it, Share It and subscribe the channel for more such videos.

          

What Is Zoning - SAN Switch Tutorial Part 2

What Is Zoning - SAN Switch Tutorial Part 2

This videos explains what is Zoning why we need zoning and what are the types zoning and difference between them In SAN Switch.

What Is Zoning - SAN Switch Tutorial Part 2

What is WWNN and WWPN ?

WWNN stands for World Wide Node Name and it a unique identification for each device or nodes connected in SAN network.

WWPN  stands for World Wide Port Name. If any devices like or SAN storage array in SAN network has FC ports on it. Then it will have a unique identification which is WWPN.

Each device in a fiber channel Network will have a unique WWNN for each vendor and the Ports under it will have WWPN.

What Is fcalias, device-alias and alias?

fcalias and device-alias are CISCO SAN switch terminology. The WWPN are hard to remember hence an alias name is created for WWPN for easy reference. We can use fcalias within a single VSAN but devices alias are span across VSAN.

Similarly alias is Brocade SAN switch terminology. We can use alias for easy reference of WWPN. It is a 64bit address which is unique to each vendor.

Why We Need Zoning ?

There are various reason for zoning. The most important is security. In a SAN network many devices are connected to SAN switch. In order to make sure that the traffic flows between the intended device we create zoning. Zoning provides a secure path between an initiator and a storage array.

What Is Zoning ?

Zoning is binding or grouping of initiator port and target ports which ensures flow of traffic between a particular initiator and target. Zoning involves 3 to 4 steps which is performed in SAN Switch.

What are the types of Zoning ?
In simple terms there are two types of Zoning Hard Zoning and Soft Zoning.In most environment soft zoning is used. Hard zoning is very rare but as its more secure then soft zoning it is used for highly secure SAN network.

Difference between Hard Zoning and Soft Zoning ?

In Hard Zoning Domain ID and Port number of Switch are used to do zoning but in soft zoning WWPN of the Port or fcalies are used for zoning. Hard Zoning is highly secure then soft zoning.

In case of Hard Zoning If any physical changes in SAN network like cable swap between SAN switches happens then rezoning needs to be done. In case of Soft Zoning any physical changes like cable swap between SAN switches does not impact anything.

Check out the below videos for more details and subscribe to You Tube Channel for more such videos.


                    

Basics Of SAN Switch - SAN Switch Tutorial Part 1

Basics Of SAN Switch - SAN Switch Tutorial Part 1

This videos explains a very basic concept of SAN switch. In later video we will discuss more on SAN switch.

What Is SAN Switch ?

SAN Switch is a hardware which have FC Ports. Host and Storage device are connected to it
It establish a communication link between host and storage device.

A Group of SAN switch is called as Fabric. Every SAN network has two fabric for redundancy. Popular Vendor Are Brocade and

Types Of Ports In SAN Network

F_Port: This is called as fabric port. This port is configured in SAN switch. This port connects to N_Port via fiber cable.

N_Port: This is called as node port which represents a target or host port. N_Port are connected to F port in SAN Network.

E_Port: This is called an expansion port. A port is which is designated an E_Port connects to the E_Port of another switch, to enlarge the switch fabric. This link is also called as Inter Switch Link (ISL).

G_Port: This is a generic port that can operate as either an E_Port or an F_Port.

Simple Architecture of SAN Network.

Below diagram show a simple connectivity of SAN switch in a Storage Area Network. This picture also shows the types of port in it.

Complex Architecture of SAN Network.

Below diagram show a complex connectivity and architecture of Storage Area Network.

Checkout out the below YouTube Video for explanation.