allocating and managing storage for generic iscsi

8/10/2019 Allocating and Managing Storage for Generic Iscsi

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Welcome to the VNXe Series: Allocating and Managing Storage for Generic iSCSI.

Click on the Supporting Materials tab to access the Student Resource Guide and course navigation

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This course discusses the concepts and tasks required to integrate the VNXe Series platform

into a Generic iSCSI environment. Focus is placed on the features of the VNXe Series and its

configuration.

This course is intended for those with knowledge of iSCSI who are responsible for managing

the VNXe Series.


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VNXe Series: Allocating and Managing Storage for Generic iSCSI

Copyright 2010 EMC Corporation. Do not Copy - All Rights Reserved.

Here is a typical iSCSI environment.The iSCSI clients are accessing storage on the iSCSI Servers.

When the VNXe is introduced, the iSCSI disks are migrated to the VNXe for the benefits of

storage consolidation, management and protection. The clients iSCSI volumes now reside onthe VNXe.


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[Insert Course Title]


In order to provide this transparent storage capability the operating system uses the iSCSI

protocol to access the remote storage on the VNXe. The iSCSI protocol is a block-level protocol,

like the SCSI protocol, but instead of being limited to a locally connected cable, it can betransmitted over network switches and routers. The iSCSI server connects to the VNXe using an

iSCSI initiator; . The iSCSI initiator can be implemented as software or as hardware. Once

configured, the iSCSI Initiator establishes a connection with the VNXe. Optionally, this

connection can be secured by using CHAP, the Challenge Handshake Authentication Protocol, to

validate each end of the connection.

Once the iSCSI connection to the VNXe is established and the storage is formatted at the

operating system level, the host can utilize it to store its data.

If multiple iSCSI attached hosts are being configured, it may be helpful to configure an InternetStorage Name Server (iSNS) in the environment. An iSNS server provides a centralized

configuration repository of iSCSI resources, and can reduce the amount of manual configuration

required on servers.


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Shown are the requirements for implementing VNXe Generic iSCSI storage.


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In the most simple configuration, iSCSI Hosts can connect to storage on the VNXe using the same

network interface cards (NICs) that iSCSI application users use to access the iSCSI Host. However,

as you can see from this diagram, there is contention for bandwidth on both the iSCSI Host NICsand the network overall. To alleviate this potential bottleneck, and ensure that the Host can

access the virtual disks in an optimal environment, it is recommended to have at least one

additional NIC in the Host that is connected to a private network, that is used for only iSCSI

traffic. By doing this, the load can be distributed across multiple components.


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This module explains how to allocate iSCSI VNXe storage for iSCSI Hosts.



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Here are the high-level steps required to allocate iSCSI storage on the VNXe and then configure

the Host to utilize that storage. The first step is to validate the iSCSI Server configuration . The

iSCSI server should have been configured during the VNXe initialization process. If it is notconfigured, or if you wish to configure an additional iSCSI server, do so now. For more

information on configuring an iSCSI server, see the course titled VNXe Series: How to Connect

and Configure Your System for the First Time. Once the iSCSI server is correctly configured,

configure the iSCSI Virtual Disks on the VNXe. This includes configuring iSCSI Host access to the

VNXe Virtual Disk .

Next, on the iSCSI Host, optionally configure and install the Celerra VSS Provider and

multipathing. Then, install and configure the iSCSI Initiator . This will allow you to connect to

the iSCSI Virtual Disk on VNXe. Once visible to the server, it can be initialized for use by the

operating system. Finally, you can use the migration method of your choice to move data fromthe local storage to the VNXe storage, if necessary.

These steps will be discussed in more detail throughout the remainder of this course.


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The first step is to validate that an iSCSI server has been created. In this example, the iSCSI server

has been created.


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Creating Generic iSCSI storage is accomplished through Unisphere, the VNXe Management Interface.

The Create Generic iSCSI Storage Wizard steps are listed. Step details will be described on the following

lides and the entire process with be demonstrated later in the course.


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Next, the storage pool is selected and the storage size is configured. One storage pool called

Performance exists on this system. It has ~487GB of capacity available for configuration. The

size desired is specified here.

Thin provisioning is enabled here if desired. Thin provisioning provides the capability of

consuming the storage as needed. In this example, the size of the storage is 100GB. If thin

provisioning were enabled, the initial allocation for this virtual disk would be about 1GB, or 10%

of the size of the storage.


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When creating storage, you are prompted to select the protection strategy. The choices are no

protection, configure protection storage but no snapshot schedule, and configure protection

storage and a snapshot schedule.


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Next, iSCSI host access is defined. If the iSCSI host already exists in the configuration, simply

select it and specify access.

If it does not, the new iSCSI host needs to be defined. In this example, it does not already exist

so Create New Host is selected.

The Create New Host wizard requires the IP address and IQN number of the iSCSI host that the

storage is being created for.


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Hosts are granted access using two pieces of information: The IP Address or DNS Name, and the IQN. In

order to obtain the iQN, you will need to launch the iSCSI Initiator on the host. The iSCSI Initiator is

oftware that takes disk I/O requests and forwards them to the network instead of a local disk. ForWindows 2003 systems, you will need to download and install the iSCSI Initiator software.

For Windows 2008, the iSCSI Initiator software is installed as part of the operating system but needs to

be enabled. You can do this in one of two ways. The first method is to click the iSCSI Initiator entry in

he Control Panel. This will generate a prompt notifying you that the service is not set to automatically

tart. If you click the YES button, it will start the service and change it to start automatically. The

econd method is to use the Services Panel. From here, it is treated as any other service. Simply

onfigure the service to start automatically and click the start button to activate it now.


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Once the iSCSI Initiator is started, you can launch it from the Control Panel or the Start Menu. Navigate

o the Configuration Tab and note the Initiator Name. That is the IQN that is required to configure the

torage on the VNXe. Please note that the iSCSI Initiator looks slightly different on Windows 2003,Windows 2008 R1 and Windows 2008 R2. This course was developed using Windows 2008 R2.


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This demonstration shows the process of creating an iSCSI Virtual Disk on the VNXe.



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This module explains how to attach iSCSI VNXe storage to iSCSI Hosts.



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Here are the steps required to attach VNXe iSCSI storage to an iSCSI Host.


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If you choose to implement multipathing on the iSCSI Host, these are the options:

EMC PowerPath on any Windows or Linux server

Windows Server 2008 native failover

Linux native multipath failover

Any of these options will provide path failover should one of multiple paths (connections) to the

VNXe system fail.

Module 4 includes a discussion about multipathing, and the installation and configuration of

PowerPath and Windows MPIO. Please view the optional module if you plan to implement

multipathing for iSCSI.


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The Celerra VSS Server Provider for iSCSI runs as a Windows service and provides the interface

between the Microsoft Volume Shadow Copy Service (VSS) and certain VNXe functions. The

Celerra VSS Provider for iSCSI enables VSS requestor applications, such as VSS-enabled backupapplications, to make shadow copies of VNXe iSCSI virtual disks. This provider is available from

the software downloads section of the EMC Online Support website.

VSS provides the backup framework for Windows Server 2003 and Windows Server 2008 and

enables the creation of shadow copies point-in-time copies of data. VSS integrates with front-

end applications so they can create and access shadow copies.

Because the Celerra VSS Provider for iSCSI is a hardware-based provider that works on the VNXe

iSCSI Servers, it reduces the load on the CPU and memory of the iSCSI host. It is also more

efficient in an environment where shadow copies of multiple volumes must be takensimultaneously. This provider supports a maximum of 2000 snapshots. EMC Replication Manager

has a built in VSS hardware provider that replaces the Celerra VSS Provider for iSCSI in

configurations using Replication Manager to create consistent shadow copies.

EMC recommends that you install the Celerra VSS Provider for iSCSI on the host that will use the

Generic iSCSI storage with backup applications (such as Networker or VERITAS Backup Exec),

other than EMC Replication Manager.


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Several additional options can be configured within the iSCSI Initiator. One such option is the

iSNS server. As previously mentioned, using an iSNS server reduces the amount of manual

configuration that must be done on the host. If you have deployed an iSNS server in yourenvironment, you can configure it on the Discovery Tab of the iSCSI Initiator . Clicking the Add

Server button will open a dialog box where you can input the iSNS server information.

CHAP Authentication can also be configured. CHAP stands for Challenge-Handshake

Authentication Protocol. CHAP verifies the identity of the peer by means of a three-way

handshake. This authentication method depends on a "secret" known only to the authenticator

and the peer. The secret is not sent over the link. CHAP authentication can occur one-way or

both ways.




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It is recommended that the Windows MaxRequestHoldTime parameter be set. The

Windows MaxRequestHoldTime parameter is the maximum time in seconds that requests

are queued if the connection to the target is lost and the connection is being retired. After thishold period, the requests are failed, an error (no device) occurs, and the device (disk) is removed

from the system. If a virtual disk in a VNXe Generic iSCSI storage resource goes offline while a

snapshot of it is being taken, an error (delayed failure) occurs. To avoid either of these errors,

use the Registry Editor (regedit.exe) to adjust the value of the Windows

MaxRequestHoldTime parameter for the Microsoft iSCSI Initiator to 600 (decimal) or 258

(hexadecimal).

To configure MaxRequestHoldTime , use regedit.exe to access the registry. Find the

MaxRequestHoldTime parameter and change it as specified.


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If configuring iSCSI storage on a Windows 2003 Server, you will need to change the disk

alignment prior to formatting the disk. Earlier versions of Windows create logical partitions in

such a way that they are misaligned with the physical layout of disks, and as a result, can causeperformance degradation. While this is not readily apparent under light loads, intense I/O

applications can encounter severe performance bottlenecks. Properly aligning the partitions

before formatting them can alleviate these performance issues. Note that it is critical that this

process be executed before formatting and using the disks, as it is a destructive process which

will destroy any data stored on the disks. Windows 2008 is not affected by this issue.

This is done by using the diskpart utility, which is included in the operating system. There are

three steps involved in aligning the disk.

1. Launch diskpart.exe from the command line2. Select the disk that you want to align

3. Create a partition on the disk

If unsure of the disk number, it can be obtained from the Storage Management section of

Computer Management or by using the diskpart command list disk.




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This demonstration shows the process of attaching a VNXe iSCSI Virtual Disk to an iSCSI Host.



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This optional module discusses how to configure high availability for an iSCSI connection.

View this module if you are planning to implement multipathing.



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The image depicted here shows a single server connected via iSCSI to the VNXe. The server is

utilizing a single NIC to connect to the VNXe. If for any reason, the NIC, or the switch it is

connected to, fails, the server will lose all connectivity to its storage.

Multipathing is a storage term that is used to describe utilizing multiple, redundant paths to a

storage resource. True multipathing requires that all components involved in connectivity be

redundant, or duplicated. This not only provides fault tolerance, it also provides additional

bandwidth that can be utilized to improve performance. Since duplicating all of the components

is not always feasible, it is possible to make portions of the solution redundant typically those

portions that have a higher chance of failure or disruption.

The simplest option is to add an additional NIC into the server , providing two paths into and out

of the server, as well as two IP addresses to prevent a duplicate IP error from compromising acritical service. In addition, a second IP address can be assigned to the iSCSI server on the VNXe.

This can be done on the same Ethernet Interface that the first address is bound to, or on a

second interface, which provides better redundancy. Ultimately, the best form of protection is to

have a completely separate network connecting the second server and VNXe NICs, which is

configured to use different switches.

Multipathing requires additional software to be installed on the server. This can be either EMCs

PowerPath product, that is optimized to operate with EMCs various storage offerings, or

Microsofts Operating System Native software, known as MPIO. For Windows 2003, the MPIO

software is installed with the iSCSI Initiator. For Windows 2008, it is installed as a feature of theOperating System.




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This demonstration shows how to install EMCs PowerPath multipathing software on a Windows

Server.


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Enabling the native MPIO in Windows 2008 is straightforward. From the Server Manager

console, select the Add Features option,. From the list, choose Multipath I/O and Install it. The

server may need to be rebooted once the installation is complete.




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Once the MPIO software is installed, it needs to be configured. Within the Control Panel, there

will now be an MPIO entry. Select this, and it will launch the MPIO Properties dialog box. Click

the Add button, and enter the information exactly as shown here EMC followed by 5 spacesCelerra.

You will need to reboot once you make the changes.




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This demonstration shows how to configure Multipathing for iSCSI connectivity on a Windows

Server.



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Once PowerPath is installed, a triangular icon will display in the System Tray to show that it is

active on the host. You can use that icon to launch the PowerPath Console. The console

provides a graphical view of the storage connections on the host, including the connected arraysand their associated IP addresses, and all attached disks. Selecting a disk will show the available

paths to it, and the Adapter will also show all paths to all disks. Note that only a single adapter

will show when using iSCSI, as it represents the iSCSI Initiator.

Once Multipathing has been configured, you will see two paths to each disk on the VNXe, one

for each session that is configured.




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This concludes the instructional portion of this training. These are the key points that have been

covered.

Please proceed to take the assessment.


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allocating and managing storage for generic iscsi

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