Using SANRAD V-Switch as the VSS Hardware Provider for Windows Backups

Introduction

Many Microsoft Window applications (like Exchange, MS-SQL, etc) are critical to the daily core functionality for many companies and organizations. Managing the data backup for these applications presents new challenges for system administrators. While there is an ever increasing need for more and more data to be backed up, at the same time the system administrator must cope with the issue of shrinking backup windows in which the application can be taken offline in order to backup the application data. Another issue to contend with is the performance hit the production server takes when backup is running.
Microsoft Volume Shadow Copy Service (VSS) and SANRAD iSCSI V-Switch acting as VSS storage provider can help the system administrator resolve these issues by:
Eliminating the need to take the application offline.
Quickly responding to the increasing need for storage.
Enabling fast backup and restore by backing up to disks and offloading the backup performance hit from the production volumes and servers.

This application note describes VSS, how it works, the required basic configuration in order for VSS to work with the SANRAD V-Switch to create snapshots as well as the backup design options using VSS and SANRAD V-Switch. We use Veritas BackupExec (V10.0) to help us demonstrate taking backups with VSS using SANRAD V-Switch.
This application note assumes that the user has basic knowledge of how to use SANRAD V-Switch to configure volumes and expose them to the servers as disks. The user should also be familiar with Microsoft Iscsi initiator for connecting Windows 2003 server to the exposed iSCSI volumes by the SANRAD V-Switch.

What is VSS? Microsoft Volume Shadow Copy Service (VSS) provides the backup infrastructure for the Windows Server 2003 operating systems, as well as a mechanism for creating consistent point-in-time copies of data known as shadow copies or snapshots.
VSS can produce consistent snapshots by coordinating between different applications (business, file-system services, backup) and storage hardware.

The following steps describe VSS Architecture:
STEP 1. Path 1: The Requestor (usually a backup application) make a request to VSS (running on the application server) to create snapshots of production volumes so that backups can be made from the snapshots and not from the production volumes.
STEP 2. Path 2: If the volumes belong to an application that has a VSS Writer (VSS aware application like Exchange), the VSS requests the Writer to prepare the volumes. The Writer will usually flash the data to the disk and freeze IO writes from the application during the time the VSS takes the snapshots (usually few seconds). This ensures application data consistency when recovery is needed. If there is no VSS writer then VSS will go directly to the next step but there is no guarantee that the data is in a consistent state.
STEP 3. Path 3: VSS requests a provider to create a snapshot. There are three kinds of VSS providers: Hardware, Software and System. A system provider is part of the Windows 2003 OS and it will take snapshots and keep them but only at the OS level. A hardware provider is usually a storage provider, like SANRAD Iscsi V-Switch, which creates and maintains snapshots at the storage hardware level. VSS chooses the provider from a list (first on the list with priority given to hardware provider if one exists).
STEP 4. Path 4: VSS goes back to the VSS Writer (if it exists) and allows it to unfreeze the application I/O activity and resume normal activity.
STEP 5. Path 5: VSS goes back to the requestor (backup application) and gives it the location of the snapshots so it can start the backup from the snapshots.
STEP 6. Path 6: Once backup is complete, the requestor informs VSS which in turn informs the VSS provider to delete the snapshots.

Summary
The combined solution of Microsoft Volume Shadow Copy Service (VSS), SANRAD V-Switch as the VSS storage provider and backup VSS aware applications (like Veritas BackupExec V10) allow companies to offload backup jobs from the production environment, leave applications up for user access while backing up the data and have a data life cycle for regulations compliance.

SANRAD is a leader in IP Storage Networks enabling organizations to effectively Access, Share & Manage Stored Data across Standard Ethernet Environments.

SANRAD delivers simplified networked storage with excellent price/performance by coupling open IP storage connectivity with comprehensive network-based data management using IP Storage Area Networks (IP-SANs).

With SANRAD, organizations of all sizes can leverage the benefits of networked storage to link employees and clients with stored data for full storage availability, flexible and scalable storage using an economical Ethernet (IP/SCSI) network.

for further reading:

http://www.sanrad.com/objects/support/Library

http://www.sanrad.com/iscsi.asp?IP-SAN=231

Symbian Mobile Phones

A phone using the Symbian operating system is able to integrate several software applications at once, such as word processors, internet browser and email. The first phone on the Symbian OS was the Nokia 9210. It was launched in 2000 and was a fairly ordinary-looking handset with the old style black-on-green screen and simple keypad...at first glance.

Opening it up revealed a full QWERTY keyboard and colour screen, almost like a mini laptop. It could be used to send emails, browse the internet and it featured a word processor, spreadsheet, presentation viewer and file/contents manager. All this from a fairly basic-looking handset.

Since the 9210 the Symbian OS has appeared on several new handsets, with more and more software being developed to make use of them. A regular feature on the Symbian OS is the ability to send and receive emails as well as access instant messaging, full internet access and even hook the handset up to your TV.

Nokia seems to have cornered the market in Britain when it comes to Symbian phones, with handsets in all shapes and sizes from clamshells to sliders to PDA's. There's even a handset which looks like a small camcorder; the Nokia N93i is capable of video capture of DVD quality, as well as mobile TV software to turn it into a portable television.

But Nokia are by no means the only manufacturer to jump on the Symbian bandwagon. Ericsson, LG, Samsung and Motorola all have handsets carrying this technology too. The Motorola Z8 also carries yet another new feature; a 'kick-slider'. This means that when the phone slides up, it forms a curve which fits the shape of your face letter than a standard handset would. Not exactly a feat of modern technology, but sometimes the simplest things are the best.

While Symbian phones are the top end of the technology spectrum at the moment, they're still reasonably priced. Some are even available on a pay as you go tariff, for those who don't want to be tied to a monthly package. Look on the internet and mobile phone retailers for the best deals.

Look for pay monthly or pay as you go mobile phones on the Symbian OS. Compare tariffs and deals on mobile phones before you buy. You can often find the best deals on mobile phones if you buy online.

J Tillotson is a UK author specialising in technology and communications.