Malta: Troubleshooting Exchange Backups

Last Updated: 26 August 2016

Article authored by Casper Manes.

One of the most important things you can do to insure business continuity, disaster recovery, and happy executives, is to perform Exchange backups on a regular and a frequent basis. Whether you have a disk failure, a datacenter disaster, or just an end user who is a bit trigger-happy on the Delete key, being able to restore data is a critical function of administering an Exchange environment.

In this post, we aren't going to talk about the merits of incremental versus differential backups, or when you do or do not want circular logging. Nor will we preach the importance of performing regular restores or storing backups offsite. We just want to focus on troubleshooting when backups either fail, or fail to complete in the time allotted.

Understanding how Exchange backups work

Before you can really troubleshoot something effectively, you need to understand how it is supposed to function when everything is right with the world. Exchange backups could be covered by an entire series of blog posts; fortunately, which Microsoft's Exchange Team has already done that.

It's a few years old but still completely relevant, and you should check out the three-part series "Everything You Need to Know About Exchange Backups" on the You Had Me at EHLO blog. Part one can be found at https://blogs.technet.microsoft.com/exchange/2012/06/04/everything-you-need-to-know-about-exchange-backups-part-1/ and the links to parts two and three are at the top of that page. It goes into VSS, COW, and DAG and is well worth the read. Go ahead, and then come back here for more.

When disk contention is just too much

One of the things that can really prevent your backups from completing is disk contention. Consider you want to make a copy of ALL the data on a disk, or volume, or maybe just a database, but to backup all that data means you need to read all that data. That's a LOT of disk I/O to contend with.

If nothing else is going on, that should be pretty straight forward, but what are some of the other things that may be happening to that disk which could fight for disk access? Other disk intensive operations that might trigger during backup windows include

  • Archiving operations
  • MRM policies
  • Indexing
  • Full antivirus scanning
  • Compliance/DLP searches
  • Mailbox moves

If any of these activities are taking place at the same time that backups are attempting to run, your disk subsystem may just not be able to handle all the activity, and that can lead to backup failures. In addition to competing processes, look as the disk queue length in Performance Monitor, and if you see double-digits, suspect disk contention.

Locks (and keys)

Certain operations can place locks on mailboxes, and if there are too many locks, or if a lock lasts too long, a backup can fail. For example, mailbox moves will lock the mailbox at a certain point to complete the move. Also, too many clients all accessing the same mailbox concurrently can place a number of read operations against the mailbox. Above 10 and any subsequent requests will immediately fail with an error MAPI_E_TIMEOUT (0x80040401) rather than being queued.

Depending on the backup solution you are using, you may also have mailboxes or content within a mailbox that is encrypted. Backup solutions that grab binary data won't care about encryption, but the ones that try to read items (either for deduplication purposes or to only backup specific items) can fail when they cannot read the mailbox or items within it, because they don't have the keys necessary to decrypt the data.

Review your logs to ensure a lock operation or failure to read operation causes the backup to fail, and if it does, dig deeper to find the cause of the lock or consider an alternative where data cannot be decrypted.

Tools to use

In addition to review the log files on the operating system and within the backup software, the VSSTester script from Microsoft can be used to diagnose backups on Exchange 2010, 2013, and 2016. As the name implies, it looks at the functions that use the Volume Shadow Copy Service, which includes both the Exchange Information Store Writer and the Exchange Replica Writer, both of which are leveraged by many different backup applications. The script both creates a disk shadow backup of a targeted database to ensure proper operation, and then performs diagnostics to determine where problems may reside.

You can download the script from https://gallery.technet.microsoft.com/scriptcenter/VSSTesterps1-script-4ed07243 and read more on how to use it, including what logging you need to enable to get the most out of it, from https://blogs.technet.microsoft.com/exchange/2013/04/29/troubleshoot-your-exchange-2010-database-backup-functionality-with-vsstester-script/.

If you are having problems with your Exchange backups, understanding how backups work, what can cause them to fail, and having the right tool to help diagnose the issue are all essential to troubleshooting the issue, and resolving it. It will take some homework before the script will be really useful to you, but if you're running into issues, the above will sort you out in most cases.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

 
Some comments from our readers…
“The articles are extremely timely and highly applicable”
“I often find critical information not available elsewhere”
“As in-house counsel, Mondaq’s service is of great value”

Up-coming Events Search
Tools
Print
Font Size:
Translation
Channels
Mondaq on Twitter
 
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
 
Email Address
Company Name
Password
Confirm Password
Position
Mondaq Topics -- Select your Interests
 Accounting
 Anti-trust
 Commercial
 Compliance
 Consumer
 Criminal
 Employment
 Energy
 Environment
 Family
 Finance
 Government
 Healthcare
 Immigration
 Insolvency
 Insurance
 International
 IP
 Law Performance
 Law Practice
 Litigation
 Media & IT
 Privacy
 Real Estate
 Strategy
 Tax
 Technology
 Transport
 Wealth Mgt
Regions
Africa
Asia
Asia Pacific
Australasia
Canada
Caribbean
Europe
European Union
Latin America
Middle East
U.K.
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.

Disclaimer

Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.

Registration

Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.

Cookies

A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.

Links

This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.

Mail-A-Friend

If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.

Security

This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.