Tip

Managing mirrors

Managing mirrors
Rick Cook

Mirroring is an increasingly important storage management technique as storage volumes grow and backup windows shrink. In mirroring, data is written to more than one logical volume simultaneously, for increased read performance and/or backup. In modern systems the data is often written to three or more logical volumes so that one volume can be split off for backup while still maintaining a redundant active copy.

Requires Free Membership to View

Veritas points out that mirrored systems are most vulnerable to failure between the time the volume is broken off and the time it is completely resynchronized with the other volumes. To minimize this vulnerability, and to improve performance, the company recommends scheduling resynchronization of the broken mirror during periods of low I/O activity. Resynchronization and regeneration are I/O intensive operations and doing them during periods of high activity not only can degrade performance for users, it takes longer and that stretches the window of vulnerability.

The company also recommends mirroring critical files to more than three volumes for added redundancy.

Veritas has a white paper on best practices for managing Windows volumes online at its website at http://www.veritas.com/us/products/whitepapers.html.


Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last twenty years he has been a freelance writer specializing in storage and other computer issues.

Did you like this tip? Whether you did or not, why not let us know. Drop us an email and sound off.

Related Book

Data Replication: Tools and Techniques for Managing Distributed Information
Author : Marie Buretta
Publisher : John Wiley & Sons
Published : Feb 1997
Summary :
Today's distributed databases increasingly require the creation and management of multiple copies of the same data. Successfully managing this data is the complex task explored here. After an overview of data replication terms and technologies, this book reviews approaches to data replication offered by new software tools from IBM, Sybase and others. There are alternative design strategies for enterprise-wide databases that can handle replicated data. And finally work plans provide detailed guidelines on selecting the right mix of replication tools and verifying that they work successfully.


This was first published in May 2001

There are Comments. Add yours.

 
TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.