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What is Zmanda Cloud Backup (ZCB)?

ZCB is the complete backup solution for Windows servers. It backs up file systems and live applications such as Microsoft Exchange and SQL Server to a highly dependable storage cloud – Amazon S3 or Google Cloud Storage.

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What is a backup set?

A backup set defines the parameters (the what, where, when, and how) for backing up a group of directories or an application such as Exchange. Each backup set can only be of a single type. For example, you cannot back up an Exchange server and Windows System state in the same backup set. Instead, you must make a backup set for each.

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What is the amandabackup user?

All ZCB services run as amandabackup user. During installation, the amandabackup user is added to "Backup Operators", "Administrators" and "Users" user groups. This user is essential for ZCB functionality.

Please see What is the amandabackup user? for more details.

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What do you mean by "full", "differential" and "incremental" backup levels?

ZCB supports full, differential and incremental backups.

  • Full backup: ZCB will back up all the data associated with the backup set. This is also called backup level 0.
  • Differential backup: ZCB will back up only the data which has changed since the last successful full backup. This is also called backup level 1.
  • Incremental backup: ZCB will back up only the data which has changed since the last successful full or last incremental backup. This is also called backup level 2 or more.

For more information, please see What are Incremental and Differential backups?

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ZCB Features

What are the different ways in which ZCB can perform backups?

ZCB supports the following ways to perform backups:

"Backup to Cloud"

This operation means that ZCB will start uploading data as it begins getting backed up. No local copies of backup data will be available. Since the data is only available on the cloud, the retention policy configured under the "Cloud Storage" heading of "Backup Where" section will be applicable.

"Backup to Disk"

This means that ZCB will backup data to local disk. Please note that under this operation, ZCB will not upload backed up data automatically. It is expected that user will launch an upload operation separately at a later time, according to user's preference. If the user doesn't upload backup data, only the retention policy configured under the "Local Storage" heading of "Backup Where" section will be applicable.

"Backup to both Disk and Cloud"

This means that ZCB will make two copies of backup data – one each on disk and the cloud. To make backup operations fast, this operation is a two stage process. First, the data is backed up to local disk. Once this is complete, a copy of data is uploaded to the cloud.
Since the data is available both on disk and the cloud, the retention policies under both "Local Storage" and "Cloud Storage" headings on "Backup Where" section will be applicable.

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Can I do backup and upload at the same time?

Yes, you can choose the "Backup to Cloud" operation which starts uploading data as it is getting backed up. However, please note that no local copies of data will be available in this case.

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Can I install ZCB on multiple machines and use the same license on all of them?

Yes, a single ZCB license can be shared across an unlimited number of systems. Please note that all such systems can potentially access the data backed up by other systems (via Tools>Restore Catalog menu option). Any machine that needs to be completely separated should have its own license. Encryption can also be used to prevent data cross-contamination.

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What file extensions you support?

ZCB supports backup and restore of all types of files.

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Is ZCB HIPAA compliant?

ZCB supports various requirements to comply with HIPAA regulations when it is properly configured and is implemented as part of a fully HIPAA compliant solution. When applied to cloud backup, HIPAA regulations largely apply in two areas - data privacy and data security.

Data privacy: The backup data is transmitted to cloud datacenters over 128 bit SSL channel. The backup data can be encrypted on the ZCB machine, before it leaves the customer site. Encryption is performed using standard RSA RC4 algorithm and the encryption keys are owned and managed completely by users and hence once data is encrypted, it can't be decrypted by either Zmanda, Inc or the cloud provider.

Data security: ZCB provides support for backup to multiple cloud geographic locations to mitigate the risk of failure. ZCB backup data is never transmitted to Zmanda, Inc servers and is stored only on datacenters managed by the cloud provider.

Since customer authentication details are known to Zmanda, Inc, the data stored on cloud servers can be accessed by Zmanda, Inc technical support engineers to resolve customer issues. This access, however, is only upon customer request and is stringently monitored by Zmanda, Inc management.

The backups are stored in the cloud in special buckets that can be accessed only by ZCB. Once ZCB transfers data to cloud data centers, the cloud provider safeguards and manages the data as per their published security policy document. Please refer to documentation provided by Google Cloud Storage or Amazon S3 for more details on data privacy and data security measures.

For more information about HIPAA compliance, please see

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Using ZCB

How do I enable VSS (Volume Shadow Services)?

The Volume Shadow Copy Service must be enabled for ZCB backups. Although the Volume Shadow Service is enabled by default, it may have been turned off after Windows installation.

To ensure that it is running:

  • Right-click the My Computer icon and choose Manage from the popup menu.
  • Expand the Services and Applications tree and locate the Volume Shadow Copy Service.
  • If it is not started, do so.
  • If necessary, change the General Properties to make the Startup Type Automatic rather than Manual.

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How can I manage my backup sets?

Backup sets are listed along the left edge of the ZCB display. You can delete, deactivate, or validate a backup set by right-clicking on it and choosing from the pop-up menu.

Backup set names are limited to 32 alphanumeric characters. A backup set must be activated (which is the default state) for the backups it defines to actually be performed as scheduled.

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What happens when I "deactivate" or "validate" a backup set?

Deactivating a backup set: Doing this on a backup set would mean that no operations such as backup or restore can be performed on that backup set. All scheduled tasks for this backup set are disabled too.

Validating a backup set: This is a simple way to check whether the essential configuration for the backup set is correct or not. If there are errors during validate, it indicates that the ZCB won't be able to use the configuration provided by the user to perform backup/restore operations correctly.

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When should I use differential or incremental backup levels?

Choosing differential and incremental backup reduces the amount of data to be backed up and uploaded to the cloud. Incremental backups can be smaller in size compared to differential backups. But, differential backups allow for faster restoration compared to incremental backups. Please see What are Incremental and Differential backups?

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What do I configure in the "Local Storage" section on the Backup page?

If you want to keep backup data just on the cloud, you don't need to configure the Local Storage section. This will be the case when you use Backup to cloud operation in ZCB 4.0 and above.

However, if you wish to put backup data to a local disk (Backup to Disk or Backup to both Disk and Cloud operations) then you would need to configure the fields in the Local Storage section.

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Can I backup data from a mapped network drive?

Yes. ZCB supports backing up mapped drives provided the shares are accessible by amandabackup user. ZCB supports both Windows and SMB shares mapped as drives. Backup of NTFS encrypted files on mapped network drive will fail with Access Denied error.

Please see How to use external or mapped network drives with ZCB.

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Can I use a mapped network drive as the Local Storage on the backup page?

Yes. You can use a mapped network drive to store backup images. To configure mapped network drive as the backup folder, perform the following steps:

  • Ensure that amandabackup user has read and write access to the network share.
  • Map the network share as a mapped drive using the backup user and as amandabackup.
  • In ZCB Backup page, under the Local Storage section, use the browse button next to Location box to select the mapped drive.

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How do I backup NAS shares?

Please see Can I backup data from a mapped network drive?

Backups of a NAS share will behave in the exact same manner.

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Can I backup Linux clients?

Yes, using Samba. ZCB can backup data from mapped Samba shares from the Linux machine. However, locked and open files are not backed up.

There is no Linux ZCB client. Amanda Enterprise provides this functionality. Please contact for more details.

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Does ZCB support FAT32 filesystem or Netware shares?

ZCB can backup only NTFS filesystem. FAT32 filesystem can be used for Backup Folder if backup encryption is not required.

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How do I configure ZCB to back up SQL Server 2000, MS Exchange and Oracle servers?

The steps are:

  • Install and run ZCB on the server you intend to back up.
  • Go to Backup page.
  • In the "Backup What" section, choose the desired Backup Type.
  • ZCB will discover all the instances of the chosen server and automatically add them to the backup set.

Please see your User Guide for important details and requirements for backup of live applications.

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How long are the backups retained in the local backup folder and on the cloud?

Local and cloud backups are retained as specified by the retention policies entered in the Backup Where section on the Backup page. You can choose to retain backups for months, days, years or forever, based on space availability and recovery requirements.

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Do I need to restore a full backup and then restore the incremental/differential backup(s) to restore to a point in time?

No. ZCB lets you select any point in time (based on when the last backup was performed), and then automatically determines which backups must be restored.

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How do I restore to a different directory?

The Restore Page includes an option to restore to a different directory.

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Can I control the bandwidth being used by ZCB for upload/download?

Yes. By default, ZCB always attempts to use the maximum bandwidth you have available.

However, if you wish to specify the limits for bandwidth to be used by ZCB, you can specify these two values:

  • Max Upload Rate: This value, in kilobits per second, refers to the maximum bandwidth ZCB will use for uploading backup data to the cloud.
  • Max Download Rate: This value, in kilobits per second, refers to the maximum bandwidth ZCB will use for download backup data from the cloud.

ZCB allows you to set these two values both at a global level and at a backup set level. For configuring these values globally, across all the backup sets, please go to Preferences > Bandwidth. For configuring these limits at a backup set level, so that they override the global values, please go to Cloud Storage sub-section on the Backup Where section.

ZCB also supports Time-based Throttling so that uploads can be throttled when necessary and left at full speed at other times.

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My backups take a long time to complete. What can I do to speed it up?

The upload speed depends on bandwidth availability. Please see How long does it take to back up to the cloud?

However, if you believe that ZCB is not using the available bandwidth completely, please do the following:

  • Make sure that bandwidth throttling limits are not configured. Please see the FAQ Can I control the bandwidth being used by ZCB for upload/download?
  • Tweak the thread count in Preferences > Advanced. If you increase the number of threads, the upload/download generally speeds up due to concurrent data transfers. However, beyond a point the performance might not improve further, or it might even fall due to other overheads.
  • Adjust the schedules so that uploads occur when maximum bandwidth is available. You can upload multiple backup sets at the same time. 

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I cannot use the machine when backups are running. What can I do?

ZCB uses the Windows Volume Shadow Services (VSS) to perform backups. VSS minimizes impact on the system. But because system resources such as CPU cycles and memory are shared, the impact cannot be entirely eliminated.

Compression in particular can consume significant system resources.

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Why can't I change the cloud location for a backup set?

The cloud storage locations are all totally different from each other. If backup data is spread across multiple cloud locations, it will be difficult for ZCB to perform restores. Hence, once you choose a cloud storage location and save a backup set, you can't change it.
If you wish to use a different cloud storage location, please create a different backup set.

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How can I delete old backup data from cloud?

You can configure ZCB to automatically delete old backup data by configuring suitable retention policies. Please refer to How long are the backups retained in the local backup folder and on the cloud? for more information on Retention policies.

However, if you wish to manually delete data which has not expired as per the retention policy, please see How to remove data from the cloud.

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Why do I see so many User Access Control pop-up messages while using ZCB?

When ZCB is run using a non-Administrator user, one will see UAC messages on Win Vista, Win 7 & Win 2008. ZCB requires elevated privileges to create, delete & query schedules. So, when ZCB tries to create, delete or query the Windows scheduler, it throws a UAC pop-up so as to make sure that the actions are run under elevated privileges.

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Advanced Operations

Can I move existing local backups to a different disk location?

Yes. If you have been using ZCB to keep backup data on your local disk and now wish to move this old data to a new location on your machine (a different drive for instance), you can do so. For this, you will have to use the movebackup option of zwcontroller.exe program which ships with ZCB.

Please refer to the movebackup operation documentation in the Administration section of the ZCB user guide.

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How do I restore to a different machine?

The backup must reside on the cloud. Backups stored in the local backup folder cannot be restored to another machine using this process. If you need to restore in a scenario with you have no backups on the cloud storage, please open a support case.

  1. Install and run ZCB on the restore target machine.
  2. If the backup is encrypted, make sure the required encryption certificates from the backup machine(s) are available on the restore target machine. If the backup archives have been created using ZCB prior to 3.0 release, the Zmanda key container is also required on the restore target machine.
  3. From the Tools menu, choose Restore Catalog to restore the backup. You must supply a host (host name of the original server) and backup set name to identify the backup used for the restore. If backup set name is not specified, all backup sets found in the original server, will be recovered on the new server.
  4. All the recovered backup sets will be named "<backup set name> (<original hostname>)"
  5. Use ZCB to restore the files as if they were on the original machine. You can also look at the reporting information for the recovered backup sets. Please refer to the Restore section in the ZCB user guide for more information.

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Does ZCB log events to Windows Event Viewer?

Yes. All Backup, Upload, Download and Restore successful and failure events are logged. In addition, if email notifications have been configured on ZCB, any failure while sending emails will also be logged in the Windows Event Viewer.

The following output shows an example of a backup failure.

Event Type: Error
Event Source: ZCB
Event Category: Backup-Restore
Event ID: 501
Date: 7/7/2009
Time: 5:40:33 PM
User: N/A
Computer: EXCH-SERVER-1
BackupSet3 - Backup failed with errors.
Error Details : File system not supported.
Please check log files for details.

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Why is the Backup Size on the Backup Page different from the Total Upload Size reported on the ZCB Monitor Page?

The Backup Size on the Backup page shows the size of Backup archive. The Total Upload Size on the Monitor page includes the backup meta data and catalog for the archive in addition to the backup archive. So the Total Upload Size will be greater or equal to the Backup Size value. The backup archive metadata and catalog is required to recover the catalog in case of disaster recovery of ZCB machine.

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Cloud Storage

How can I verify the validity of the Cloud Certificate and Connection?

Choose Cloud->Check Cloud Connection. This causes ZCB to connect to the cloud and validate the required subscription and keys. You can use this test to validate your installation, or to troubleshoot failed uploads/downloads. top

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I'm getting subscription failure errors trying to access the Zmanda Network Downloads page. Why?

To access Zmanda Network downloads page, please  click here.

If you have chosen ZCB with Amazon, do not access ZCB product using or or Using these pages will re-generate your Amazon S3 certificate, which renders your old/current S3 certificate useless . ZCB will then fail to upload data to S3 and restore data from S3. You will have to download new S3 certificate and import it in ZCB using ZCB user interface.

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How secure is my data with ZCB and the cloud?

There are several levels of security provided by ZCB and the cloud providers that ensure privacy and security of your data:

  • ZCB provides an option to encrypt your backup data by using Digital Certificates from Trusted Certificate Authorities or using self-signed certificates you can generate yourself.
  • In addition to encrypting the backup data, ZCB provides an option to transfer your data from your computer to the cloud via secure 128-bit SSL.
  • The cloud providers have access controls that only permit authenticated access by ZCB with your own unique security certificate. You, and only you, maintain full control over who has access to your backup data.

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How to purchase cloud subscriptions?

If you bought ZCB from the Zmanda Website and downloaded both the ZCB installer and the cloud certificate, you don't need to do anything else. You can simply import the certificate to ZCB using Cloud > Import Cloud Certificate menu.

However, if you have installed ZCB but don't have a cloud certificate, then you must purchase a subscription. Please click on Cloud > Purchase Cloud Subscription to buy a Google Cloud Storage subscription for ZCB. The purchase process requires Zmanda Network login information. Please join Zmanda Network for free at

After your purchase, your cloud certificate will be available for download from Zmanda Network. Please download the certificate to the ZCB Windows server and import the certificate into ZCB.

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How much are we spending? How much have we spent in the past?

This question applies only to customers who have chosen ZCB with Amazon S3 storage.

Please click on Cloud > Cloud Billing to view billing activity and see what is being spent so far this month. You will need your Amazon account information to access the bill.

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How do I use a different account?

Every additional account requires an additional subscription, available from the Zmanda Network.

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Who sends the monthly bill?

This question applies only to customers who have chosen ZCB with Amazon S3 storage.

Monthly billing for ZCB license, storage and transfer cost will be provided by Amazon. The bill will have specific entries for ZCB in addition to entries for other Zmanda, Inc services, if you are using them.

Customers who have chosen ZCB with Google Cloud Storage do not have monthly bills. ZCB-Google subcriptions are purchased annually.

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I am facing a technical issue. How do I get support?

You can contact our support by clicking on Help > Contact Support. This will open your browser and direct it to the Zmanda Network. After logging in using your Zmanda Network account, you can open a support case from the Support tab.

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