EdgeSight Architecture

EdgeSight Architecture

Citrix EdgeSight is a performance and availability management solution for Citrix XenApp servers and endpoint devices. EdgeSight can be used to understand how systems, applications and the network perform in an environment. Through real-time monitoring and historical analysis and trending, EdgeSight can be used to improve service and support levels, as well as provide proactive management from a user perspective

EdgeSight

Citrix EdgeSight is a performance monitoring and response solution. EdgeSight uses agents on endpoint devices, such as desktops, laptops and virtual desktops and on XenApp servers to collect data about the environment.

The EdgeSight Server is a centralized server that collects data from the EdgeSight for Endpoint agents and the EdgeSight for XenApp agents. These agents provide visibility into what is happening by displaying real-time data.

Data collected in the environment by the agents is regularly uploaded to the EdgeSight Server. By default, data is uploaded once a day, but an engineer can customize the upload intervals.

An engineer can also configure thresholds, which agents compare data against, and send an alert whenever a certain threshold is met. Thresholds can be measured against items such as CPU levels, memory and network latency

EdgeSight Benefits

Citrix EdgeSight allows engineers to:

Monitor and measure actual user experience

Administrators have real-time visibility to session-level performance and can address potential issues before users are impacted.

Identify and diagnose slow login issues

EdgeSight monitors the XenApp login process, providing visibility into key metrics such as profile load time, login script execution and security authentication.

Assess the application delivery environment's status at a glance with farm, alert and dashboard views

EdgeSight identifies those users, machines and applications most heavily impacted by performance issues for fast prioritization of crucial resources.

Diagnose application performance issues in real time

The support organization can immediately locate the applicable server and analyze highly detailed session-level data to isolate and resolve performance issues.

Analyze system resources for improved capacity management

System planners are able to analyze resource consumption based on actual user sessions and applications on each server to ensure future capacity requirements are met. 

Maintenance Windows

Maintenance windows are typically scheduled for timeframes when it is assumed that there is low resource utilization in an environment, usually on weekends and out-of business hours. EdgeSight can be used to determine the best time for maintenance windows by collecting historical data that gives details about the high and low periods of resource utilization. By confirming when the lowest point in resource utilization occurs, engineers can plan the best time to perform maintenance.

Data Upload Intervals

When the agent first registers with the EdgeSight Server, it receives information about the data required by the server and when the data is to be uploaded. Engineers can configure EdgeSight to specify the time between data transfers from the EdgeSight agents to the EdgeSight Server. The default interval is one day.

Database Grooming

EdgeSight collects and stores a wide array of performance data from agent devices. Database grooming is the process of removing older data at regular intervals to make room for new data. By default, EdgeSight stores performance data for twelve months.

Installing EdgeSight for XenApp Agents

An administrator can use the following process to install the EdgeSight for XenApp agents.

1. Launch the Citrix EdgeSight installation media.
2. Select EdgeSight for Endpoints Agent for installation.
3. Read and respond to the license agreement.
4. Enter the Company name.
5. Configure the agent installation locations.
6. Enter the EdgeSight Server name and port number.
7. Start the installation.

Configuring Alert Actions to Generate an SNMP Trap

An administrator can use the following process to configure actions to alert third-party tools.

1. Log in to the EdgeSight Server browser portal.
2. Click Configure > Company Configurations > Alerts > Actions.
3. Create a new Alert Action.
4. Configure the Alert Action to generate an SNMP trap.
5. Configure the SNMP properties.

EdgeSight for Load Testing

EdgeSight for Load Testing is an automated performance testing and test case solution for Citrix environments. EdgeSight for Load Testing records a series of actions as a script and runs them as a test case against systems to simulate different types of load.

Test cases can be created by recording a session that captures the actions taken within the session and converts that into a script. These scripts can also be created manually without the use of session recording and can be edited as needed to simulate workload.

The data collected from the test case can be used to develop a scenario with a specific number of client devices, running applications and functions that are used within those applications. Engineers can then increase the level of each variable to measure the maximum number of possible users, sessions or applications that could run on a specific type of system.

One of the most time-consuming tasks an engineer faces with a performance monitoring tool, such as Citrix EdgeSight, HP OpenView or Microsoft System Center Operations Manager, is to accurately configure thresholds in an environment. Thresholds that are not configured correctly will continually send false positive alerts about items, which may not even affect the environment. Through the use of EdgeSight for Load Testing, engineers can increase the level of each variable in the scenario to determine different baseline benchmarks that can be used to set realistic thresholds within a performance monitoring tool.

EdgeSight for Load Testing is available to customers who are licensed to use the Enterprise and Platinum Editions of XenApp. 

EdgeSight for Load Testing Components

The following terms are components of Citrix EdgeSight for Load Testing:

EdgeSight for Load Testing Controller

EdgeSight for Load Testing records and creates virtual user scripts and defines the tests. When the test is ready for playback, the Controller instructs the Launchers to run the test with a certain number of virtual users for a period of time.

EdgeSight for Load Testing Launcher

EdgeSight for Load Launcher receives the commands from the Controller and generates virtual user sessions on the target XenApp servers. The number of Launchers required varies based on the target virtual user load. Launchers report session information back to the Controller for run-time and post run-time analysis.

Launchers are installed on the client devices of the servers that will be under test. They can be installed on servers that contain the Controller or installed as stand-alone launchers.

Creating an EdgeSight for Load Testing Test Case

An administrator can use the following process to create an EdgeSight for Load Testing test case.

1. Create a new script within the Citrix EdgeSight for Load Testing console.
2. Configure the test script for test case instructions.
3. Create a connection to the XenApp and XenDesktop environment.
4. Create test users for the test case.
5. Select the connection to display the list of users associated with the connection.
6. Select a recording user.
7. Start the test recording.
8. Perform the desired actions within the ICA session that should be included in the test case.
9. Stop the test recording.
10. Edit the script as needed to accurately simulate the workload according to realistic usage patterns.

Note: The script should be edited to allow for delays while the script is running to mimic an average user workflow. 

XenDesktop Architecture

XenDesktop Architecture

XenDesktop is a complete, end-to-end solution desktop virtualization system that centralizes and delivers virtual desktops to users, which improves data security by centralizing desktop management within the datacenter. XenDesktop is comprised of several Citrix component technologies that provide the essential functionality required to effectively manage, maintain and optimize all desktop connections. Identifying how XenDesktop works and how it fits into a virtual solution is a requirement for Citrix engineers.

Virtual Desktop Components

Engineers must make considerations about the following desktop components prior to integrating a virtual desktop solution:

• Streamed operating systems
• Application delivery methods
• Required privilege level
• Workload profiles
• Profile management
• User data
• Web Interface

Streamed Operating Systems

Engineers must look at several different factors when deciding whether or not an operating system can be streamed using Provisioning Services, such as:

Network Speed

Streaming an operating system on a network that is already fully utilized in a lower bandwidth network would negatively affect existing systems and the streamed operating systems.

Network Topology

Site locations and site-to-site WAN links affect whether or not streaming an operating system through Provisioning Services should be considered. If the servers running Provisioning Services cannot be located throughout the environment in close proximity on a LAN to where the target devices will be located, or the WAN links are either too slow or too small, then streaming might not be the best option.

If it is determined that an operating system should not be streamed, then it should be installed as a virtual machine with its own virtual hard disk. Installing the operating system on a virtual machine makes the operating system more static. All of the changes will be saved to it, unlike a standard mode disk that can restart the operating system to a clean reference image upon restart.

vDisk Types

The following vDisk image types can stream an operating system:

• Standard image
• Private image
• Difference disk image

Standard Image

Multiple target devices share the same vDisk image. The vDisk is configured in read-only format and any changes made by the target device are stored in a write cache file for the duration of the desktop session.

Benefits	Considerations
Many virtual desktops can be deployed from a single vDisk creating a central point of management of the virtual desktop. Desktops are reverted to a consistent state after each restart. Storage requirements are reduced as the write cache is reset after each restart.	Any application or system-level automatic updates will start after every restart. Important: Automatic updates should be disabled at the operating system and application level. Applications that are installed and data that is created by the user during the session is discarded after each restart, which may be unexpected by users.

Private Image

Each target device is provided with an assigned vDisk. The vDisk is configured in read/write format allowing any changes to be saved for further use.

Benefits	Considerations
Users are able to completely personalize their desktops and all applications. User data and configurations are saved on the vDisk.	vDisk support will become increasingly difficult as every image becomes customized for every user. Private images can require extensive storage

Difference Disk Image

Multiple target devices share the same vDisk image. The vDisk is configured in read-only format and any changes made to the target device are stored in a differential cache file. Upon restart, the differential cache file is saved and reused for future sessions.

Benefits	Considerations
Allows for greater level of customization by retaining changes made by each user. The storage savings over the use of private images is significant.	If the base vDisk is ever modified, the user changes are deleted and the user must recreate their customizations.

Application Delivery Methods in a Virtual Desktop Environment

The following application delivery methods are available in a virtual desktop environment:

• Locally installed application
• Online application
• Offline application

Locally Installed Application

Applications can be installed locally on the virtual desktop image.

Benefits	Considerations
The applications use the resources of the virtual desktop for processing. Application compatibility with the desktop operating system can be greater than with a server-based model.	Applications that are not suitable to run on XenApp should be installed locally on the virtual desktop image. For example, an application that writes registry entries to the local machine hives or one that is not programmed to the Win32 standard The resources configured for the virtual desktop must be sized appropriately to support the operating system and the applications running in it.

Online Application

Applications can be accessed by users as an online application from the XenApp server through use of the Citrix Online plug-in.

Benefits

Considerations

Online applications are installed centrally, or streamed to XenApp servers, which can ease application maintenance. Online applications are processed on the XenApp servers, taking advantage of the resources available to the server operating system. This allows for scaling of application performance regardless of the endpoint device in use. Only virtual channel information is sent to the endpoint devices accessing the online applications, which minimizes bandwidth and increases security.

Applications must be compatible to run on XenApp servers. Network connectivity must be maintained during the use of online applications.

Offline Application

Applications can be streamed from a file or web server to the virtual desktop. This application delivery method requires users to have the Offline plug-in installed on their desktops.

Benefits

Considerations

Offline applications do not have to be installed into the virtual desktop image. Offline applications use the resources of the virtual desktop for processing. Several versions of the same application can be streamed and run at the same time on a virtual desktop.

An example of an application that cannot run on XenApp is an application that writes registry entries to the local machine hives or one that is not programmed to the Win32 standard. The resources configured for the virtual desktop must be sized appropriately to support the operating system and the offline applications running in it. Offline applications with dependencies on other offline applications must be planned out as linked profiles and configured as part of the application profiling process. For more information on application streaming, see Citrix Knowledge Base article CTX116414.

Workload Profiles

An engineer can use workload profiles to identify the peak and average resource needs of the applications and the desktop operating systems. This information can then be used to determine the amount of resources that should be assigned to each virtual desktop within the environment to meet the needs of the virtual desktops and the environment during normal and peak usage.

Resource needs can be obtained by gathering performance metrics from the desktop virtualization assessment or by using the performance counters included in the Windows operating system, as well as third-party tools. The data collected should be organized to highlight the peak and average resource needs of all of the applications and the desktop operating system. This information can then be used to determine the amount of resources that should be assigned to each virtual desktop within the environment to meet the overall average needs, while accounting for peak usage periods.

Workload Profile Resource Requirements

The workload profiles for a virtual desktop environment can be determined from the resource requirements of the following items:

• The operating system that will be delivered within the virtual desktop, including:
• CPU
• Memory
• Disk
• The enterprise applications that will be running within the virtual desktop operating system, including:
• The peak and average CPU
• The peak and average memory
• The peak and average network
• The peak and average disk
• The supporting applications, such as antivirus software, instant messaging, system management applications and monitoring applications, that will be running within the virtual desktop operating system, including:
• The peak and average CPU
• The peak and average memory
• The peak and average network
• The peak and average disk 

Sizing Virtual Desktops on a Single Host Server

Profile Management

Similar to a XenApp environment, a virtual desktop environment should have a profile management solution in place.

In a virtual desktop environment in which the virtual desktop operating systems are refreshed after each session, user profiles and folders must be saved in a separate, safe location to prevent them from being deleted with the rest of the changes to the virtual desktop.

When delivering a full desktop, certain profile settings need to be saved, including aspects of the desktop interface in addition to any applications that run within the virtual desktop. This includes background colors, font selections and icon sizes.

To manage user profiles within a virtual desktop environment, Citrix Profile management is available to customers who are licensed to use the Advanced, Enterprise or Platinum Edition of XenDesktop. 

Profile management can be used to select specific parts of a profile to be saved in a separate location from the desktop at logon and logoff. Along with mandatory user profiles, this provides a method of saving the personalized user profile settings while decreasing the size of the user profiles.

Environments that cannot utilize a profile management tool, such as Citrix Profile management, must still monitor and manage user profiles.

User Data

Any data that is generated from a user should be redirected and saved outside of the XenApp server, including, but not limited to documents, pictures and PowerPoint files. Engineers must determine how to redirect and store user data in a XenDesktop environment.

In a XenDesktop environment, users are always presented with a complete desktop interface. Therefore, special care must be taken to store settings related to the entire desktop interface in addition to the applications that run within it.

Engineers can use Active Directory Group Policies to redirect user data to a network location where it is stored centrally, backed up and can be accessed from any virtual desktop. Citrix policies can also be used to redirect user data by hiding users' local drives and presenting them with network drives only. 

Web Interface

To access XenDesktop virtual desktop resources, a Web Interface server must be installed to interact with the Desktop Delivery Controllers.

By default, the Web Interface is installed and configured on a Desktop Delivery Controller. If a separate Web Interface server is in place, then the XenDesktop farm must be configured in the XenApp Web site settings through the Access Management Console.

Several Web Interface servers should be deployed to provide redundancy and performance in XenDesktop environments. These Web Interface servers can be load balanced with a device such as NetScaler VPX

Citrix - XenApp

XenApp Architecture

Citrix XenApp is an end-to-end application delivery solution that manages applications in the datacenter and delivers them to users on any device. Applications can either be installed, streamed to the XenApp server or streamed directly to the client device, resulting in simplified management and reduced application operating costs. XenApp is a critical component in any Citrix virtualized environment; therefore it is necessary that Citrix engineers are able to identify how XenApp works and how it fits into a virtual solution.

Application Delivery

When delivering an application with XenApp, it is important for an engineer to understand the different application delivery methods available and to determine which method best fits the needs of the environment. Depending on the type of application, the users accessing the application and the delivery method, applications can be:

• Installed on a XenApp server and accessed as an online application
• Streamed from a file or web server to a XenApp server and accessed as an online application
• Streamed from a file or web server to the client device and accessed as an offline application
• Accessed as a XenApp server-hosted desktop 

Online Applications Installed on a XenApp Server

An online application is processed on the XenApp server and only virtual channel information is sent to the client.

The Citrix Online plug-in is required to access online applications installed on XenApp servers.

Benefits

Considerations

Applications are installed centrally on XenApp servers, which can ease application maintenance. This method makes use of resources available to the host server operating system, which allows for scaling of application performance regardless of the endpoint device in use. Only virtual channel information is sent to the client, which minimizes bandwidth and increases security. Applications requiring significant client and server bandwidth are good candidates for online applications.

Application resources need to be installed at the server level because online applications are processed on the XenApp servers. XenApp server resources must be increased in order to scale the number of concurrent online applications in use. Applications that will not run on a server OS or on a multi-user kernel should not be installed directly on a server.

Online Applications Streamed to a Server

An application that is streamed to a XenApp server allows users to access it as if it were installed directly on the XenApp server.

Benefits	Considerations
This method allows for a centralized update process across multiple XenApp servers. This method allows for multiple versions of an application to be delivered without using separate XenApp servers. For example, Microsoft Word 2003 and 2007 can be delivered from the same XenApp server.	It is recommended to pre-cache the streamed application on the XenApp servers to enhance performance and reduce the application launch time on the client.

Offline Application

An application that is streamed to the client is streamed from a file or web server and launches on the client device as a local application. This offline application uses the client device resources as opposed to using XenApp server resources.

Benefits

Considerations

Endpoint device resources can be used for an application that requires large amounts of processing power. Applications do not need to be installed into the virtual desktop image. Application compatibility with the desktop operating system can be better than running from a server-based computing model. Multiple versions of the same application can be streamed and run at the same time on a virtual desktop An application that requires advanced video capabilities are good candidates for offline applications.

The Citrix Offline plug-in must be installed on client devices to access offline application. Clients that do not support application streaming, such as non-Windows clients, cannot launch offline applications Applications are processed within an isolated virtual environment when launched on a client device. Some applications are not suited for offline application packaging, such as those that install drivers and services.

Server-hosted Desktop

Publishing a desktop provides users access to the desktop of a XenApp server and the resources available on the server.

Benefits

Considerations

Provides users with a familiar interface. Allows thin clients to replace full PCs or desktops. Allows remote or home users to access a full corporate workspace.

Provides users access to the resources on a server which can result in configurations and settings being changed causing server vulnerabilities. Requires, as a recommendation, limiting the use of server-hosted desktops and locking down access to server resources is highly recommended. Consumes more resources on a XenApp server because an entire desktop is provided. for each connected user and the desktop interactions must be transferred to the XenApp server.

10 best practices for cloud design

Nine Best Practices for Cloud Design in a Hybrid …: http://youtu.be/HhQhP7iBqfo

This is the video of Best practices for Cloud design. Its a must see video

Data Center Migration

Note: This blog is written with the help of my friend Rajanikanth

Data Center Migrations / Data Center Consolidations
Data Center Consolidations, Migrations are complex projects which impact entire orgnization they support. They usually dont happen daily but once in a decade or two. It is imperative to plan carefully, leverage technology improvements, virtualization, optimizations.
The single most important factor for any migration project is to have high caliber, high performing, experienced technical team in place. You are migrating business applications from one data center to another and there is no scope for failure or broken application during migration. So testing startegy should be in place for enterprise business applications to be migrated.

Typical DCC and Migrations business objectives

Business Drivers

·            Improve utilization of IT assets

·            DC space & power peaked out - business growth impacted

·            Improve service levels and responsiveness to new applications

·            Reduce support complexity

·            Reduce IT costs (facility, staff, power, # of servers, taxes etc)

Data Center Migration Strategy

The Migration Strategy looks like this:

§  Data Center Migration projects usually organized in 3 to 4 phases

1.     Assessment and High Level Planning/Strategy

§   During the initial assessment phase each of the applications in scope will be analyzed and categorized according to criticality, complexity and time to move.

2.     Detailed Planning

3.     Migration execution

§  Migration Schedule will be developed after assessment

•          Migration schedule is based on

§  Risk

§  Resource Contention

§  Complexity

§  Migration Type (P2V, V2V, Build New, Forklift)

§  Migration schedule assumes WAN throughput available to support  data (GB/hour)  transfer rate from old data center to new facility

§  Waves or Move group created and mapped according to complexity of applications; workload spread over multiple weekends

§  Applications will be grouped according to dependencies

§  Current support of customer required for migrations during waves

Various Approaches to Migration

Migration strategy	Strategy to minimize required downtime	Strategy to minimize risk of failed cut-over
Physical to Virtual (P2V)	P2V requires 2 down times    P2V    Cut-Over	P2V brings a copy of the production application The copied application (non-production) can be tested as long as required
Virtual to virtual (V2V)	V2V requires 2 down times   V2V   Cut-Over	V2V brings a copy of the production application The copied application (non-production) can be tested as long as required
Build New	Build New only requires 1 down time for the cut-over.	Build new brings a copy of the production application The copied application (non-production) can be tested as long as required
Forklift	Downtime required by forklifting the hardware prohibitive (several days)	Risk of transporting old hardware prohibitive
Swing	Swing only requires 1 down time for the cut-over.

Physical to Virtual (P2V) Conversions

The Physical-to-Virtual (P2V) is one migration approach for taking a standard physical device and generating a new virtual machine automatically based on the physical device’s configurations and settings.  To accomplish a P2V migration, tools such as VMware Converter, Leostream’s P2V tool or Platespin’s Power Convert software are often utilized.  Requirements for this migration option include:

·                     Need to purchase P2V or Power Convert licenses

·                     Limits on data size when transferring across the WAN

·                     Approximately 24 hours downtime required for cut-over

·                     No non-standard drivers can be installed on the existing device

The P2V tools provide a feature called synch which gives option to do final synch after doing a full P2V image. The final delta changes can be synched during cutover window.

It is not uncommon for a P2V migration to fail/hang, therefore requiring the creation of a new virtual machine from scratch.  This risk needs to be taken into consideration when planning for application downtimes. 

Virtual to Virtual (V2V) Conversions

Existing virtual machines that are to be migrated to a different host machine in the target data center, it is possible to copy the logical server from the source VM to the destination VM.  This migration option is accomplished using the same tool(s) as the P2V option.  An advantage of this option is that the complexity of and time for testing is significantly less that other options, since the existing server is already virtual. However, it is still important to note that for a V2V migration to be possible, both the existing and future host servers must be running compatible ESX versions.  Limitations on storage size requirements should also be considered.

Rebuild New

Server that either do not meets hardware standards or have hardware issues (for P2V to go through) and application support team is comfortable to do this can be rebuilt from scratch on target VM.  This option is can be chosen when it is more cost-effective to build new than to purchase a P2V licenses.  It is important to note that with this option:

·         OS and Applications must be reinstalled

·         Installation Software and licenses must be available

·         Longer time is needed for setup

·         Business must be able to afford downtime of related IT services

The alternative to avoid business downtime is to for a Swing Approach on target VMs, which is non disruptive. However rebuild always takes longer time than any other migration approach.

Swing is a traditional migration method where target environment including hardware, OS, software are built from scratch and original environment is not affected.

Once target environment is thoroughly tested, than cutover from physical to virtual environment.

Forklift Migration

When a server is Forklifted, all of its configurations and properties must remain as-is.  Upon arrival at the target data center, the device should boot up properly with only minimal changes needed (e.g. – IP/DNS changes).  As an alternate approach, IP address configurations could also be changed prior to system shutdown at the local data center.  Servers selected for the Forklift option either have specific utilization requirements, are not up-to-par in terms of hardware standards or are set to retire in the near future. 

For a server to be Forklifted, the following should be considered:

·         Business must be able to afford significant downtime

·         Full backup of all systems is required

·         Reboot needed prior to full shutdown

·         Network changes necessary (IP, DNS, etc.)

·         Firewall updates may be required

Clone

Cloning a server involves making an exact replicate of the server onto a different physical device.  To clone a server, software tools such as DRD Clone (HP-UX), Symantec Ghost or Robocopy are typically utilized.  When cloning a device, the following should be considered:

·         Minimal downtime for applications

·         Identical hardware required – test needs to be done if it works on VM

·         Network and firewall changes necessary, unless on same LAN segment

·         Temporary software licenses may be need for applications.

·         Recommended to do POC

Database Migration

All the leading database vendors provide export/import programs in order to dump the contents of a database

to a file that can be transferred to the destination environment and imported again.  The export file will contain whatever it is specified to contain at the time of the export.  It can contain definitions of all database objects, including tables, views, grants and stored procedures that make up a complete database instance.  The export binary file is normally compatible across operating systems and versions of the Relational Database Management System (RDBMS).

This approach is the preferred migration alternative for databases and will be used when downtime is allowed

Typical Implementation Plan for Server Migration using P2V Approach

•       Phase I - Discover the server (One weekend before cut-over)

•       Install two server in Source DC (Image Server and Convert Server)

•       Un-hardening server for discover

•       Phase II - First Image the server and transfer the data (First Week)

•       Make the image for all servers

•       Send the image data from Old DC to New Data Center

•       Phase III - Final Sync (Next Week)

•       Open the firewall port for the server sync

•       Final Sync and change the service load to new server

•       Hardening the new server and setting firewall rules back

•       Phase IV - Decommission the Old Server (Post Action)

Decommission the Old Server

Data Migration Strategy

Large amount of data migration options:

§  Storage Array Based (Recommended)

§  Host Based (Volume Managers, P2V Tools)

§  NFS – Mostly for Unix only

Backup to Disk (Next to Array based, this is recommended) and ship the disk and restore. From a technical standpoint, the current and target server (VM) must have compatible drives / hardware in order to write and read the shipped tapes.

  

Data Center Site Strategy

Option 1

•          Single Global Data Center (Tier 3 or Tier 4)

•          One large DR site

•          Active - Passive

Option 2

•          Single Global Data Center ( Tow Tier 3 sites managed as one)

•          One small – medium DR site

•          Active – Active – Passive

•          More GDCs for companies with aggressive consolidation targets

•          Dedicated DR site not required with multiple GDCs

DC Classification	Tier	Hosting
Global Data Centers (GDC) Tier  3 - 4	•       5-9s availability •        Site redundancy •        24x365 staffing •       Two independent utility paths • 2N power and cooling systems • Able to sustain 96 hour power outage • Stringent site selection criteria	. ERP . Mission   Critical . Extremely high cost of downtime
Regional Data Centers Tier  3	• Two utility paths (active and passive) • Redundant power and cooling systems • Redundant service providers • Able to sustain 72-hour power outage • Careful site selection planning	. Majority of revenue from online business . High dependence on IT . High cost of downtime . Latency &bandwidth sensitive App’s . World-wide presence
Regional Data Centers Tier 2	• Some redundancy in power and cooling systems • Generator backup • Able to sustain 24 hour power outage • Minimal thought to site selection • Vapor barrier • Formal data room separate from other areas	• Some amount of online revenue generation • Multiple servers • Phone system vital to business • Dependent on email • Some tolerance to scheduled downtime

Introduction to Data Migration

When it comes to Data Migration in a Data Center Migration / Consolidation projects, some typical questions asked are:
- How do I migrate my SAN data
- How do I migrate my DAS data
- How do I migrate my Operating System Volume Groups
- How do I migrate all this data across data centers
-What is WAN link bandwidth
-What is total Storage I'm looking to migrate
-Can I migrate data given the downtime and meet my SLAs..
-How do I migrate my Database data

The answer is, it depends. It depends on the customer environment. No one solution fits all. As discussed else where in this blog, doing a proper discovery / assessment of the existing environment, re-use what existing methods/tools already existing, minimize service downtime, and most important, making sure applications are not broken during migration are key.

At conceptual level, data migration can be classified into following:
  1 - SAN (Storage Area Network) based
  2 - Host based

SAN based: with this method, SAN replication tools already existing can be used. Not necessary that SAN replication is configured between source data center and new data center. It can be used where the strategy permits. Eg:- EMC SRDF, SAN Copy, HP Continuous Access etc..
Host Based: This consumes some host based CPU cycles, but less expensive or where no SAN based technologies available. eg: Volume Mangers like - VxVM mirroring, TDMF

There are even more traditional OS based tools, mostly for unix - tar, cpio, rsync etc..these does the job and even have incremental transfer and final sync when rsync is used.

There are other vendor tools like PlateSpin Migrate, VMware Converter which are specialized for Windows/Linux workloads. PlateSpin for example is not free. It is licensed  based on per conversion or workload.

And when migrating database like oracle, it is always recommended to use oracle tools in combination with SAN replication methods. 
For OS, a jumpstart image, flar image, Ignite-Ux recovery image etc..based on OS flavor will do. When you are migrating from old storage array to a new storage array, side by side, a simple Volume Mirroring is best approach. Or what about backup & restore when none is feasible.

So it is all depends on the environment.
For example - 
what is best approach when moving from old array to new array side by side (technology refresh)
what is best approach when migrating data across data centers (DC Migration)
what is best approach when consolidating storage from DAS(Direct Attached Storage) to SAN

Data Migration Methods

	Controller based	SAN based	Host Vol Mgr	Host SW Mirroring	DB Exports	DB table copy	Standby DB	File/image copy	Backup/Restore	TDMF
Migrate all host OS	yes	yes	no	no	no	no	no	no	no	no
Storage devices supported	same type	most	all	all	all	all	all	all	all	all
Migrate direct connect devices	no	no	yes	yes	yes	yes	yes	yes	yes	yes
Migrate on-line	no	no	yes	yes	no	no	yes	no	no	yes
Change data distribution	some	some	some	yes	yes	yes	yes	yes	yes	yes
Change LUN geometry	no	no	no	yes	yes	yes	yes	yes	yes	yes
Change striping, sector offset	no	no	no	yes	yes	yes	yes	yes	yes	yes
Uses host software	no	no	yes	yes	no	no	no	no	no	yes
Need DBA	no	no	no	no	yes	yes	yes	no	no	no
Moves host appl and data	yes	yes	yes	yes	no	no	no	yes	yes	yes
Distance migration	yes	yes	no	yes	no	no	yes	no	no	yes
Uses host TCP/IP for distance	no	no	N/A	yes	N/A	N/A	yes	no	no	yes
Throughput (typ MB/s)	75-150	50-160	50-120	25-60	30-150	30-150	N/A	75-150	20-80	30-150
Throttle speed	no	no	no	no	no	no	no	no	no	yes
Interruptions	1	1	0	1	1	1	1	1	1	2
Addl software purchase req	yes	no	yes	yes	no	no	no	no	no	no

Data Center Optimization

Data Center Optimization

Data Center Migrations and Consolidation gives an opportunity for Data Center Optimization which consists of leveraging virtualization opportunities to optimize server utilization, storage tiring, Application performance over the network and server sprawl, network optimization. It also includes green IT initiatives like Power & cooling efficiency, Floor space

Consolidation & Virtualization

•        Virtualization will reduce the no. of servers in data center reducing required server power and consequently the size of the necessary cooling equipment.

•       Increase server utilization by consolidation multiple standalone workloads to virtual servers

•       Increase availability by utilizing virtual environment options like clustering across virtual servers

Storage Optimization

•       Use Tiered Storage to efficiently utilize high end storage and by migrating less-critical information to low-cost storage

•        Choose right RAID level (RAID5, RAID10 etc)  to improve application performance based on application usage patterns (read intensive vs write, large block vs small , random vs sequential etc..)

•       Move from DAS to SAN and consolidate SAN islands

•       Consolidate multiple instances of  databases instances to single instance using  Oracle RAC on high end, high performance, tiered storage

Network Optimization

•       Leverage data center consolidation to move from Application traffic over WAN to internal traffic in LAN

•       Use edge caching to improve application performance

•       Utilized FCOE instead of  traditional approach  of separating data and storage traffic across Ethernet and fiber channel

•       Consider WAN Accelerators for multi-tier applications with WAN latency bottlenecks

 Automation

•        Automate Server administration tasks – OS provisioning, patching, configuration, security compliance  etc. e.g.: 100’s of patches can be applied to Solaris using  Opsware SAS (now HP SAS) automatically without manual intervention in short change window