Backup - NAS NDMP
How To |
Supported Backup Types
NAS NDMP Backup Jobs
NAS Vendor Specific
Advanced Backup Options
Before you begin using the NAS NDMP client
for data protection operations, ensure that you have completed the required Configuration
Plan your backup jobs for this agent by reviewing the following information:
NAS NDMP clients support the following backup types:
There are several advanced options specific to NAS NDMP clients. For more information,
see NAS Options. For procedures,
see Start a Backup with NAS Options
In addition, NAS NDMP clients have the following unique backup functionality.
A two-way backup is the process of backing up data from a NAS NDMP data server
to a storage device attached to that same NAS NDMP data server.
A three-way backup is the process of backing up data from a NAS NDMP data server
to a storage device attached to another NAS NDMP data server of the same type (NetApp
to NetApp, for example). Keep in mind that the source data server does not need
to be attached to a storage device.
Multiple Data Readers can be specified for backup jobs, providing the facility
to use multiple data streams without having to create multiple subclients and start
separate backup jobs. This allows backups of multiple paths in a NAS subclient to
run concurrently, as part of the same job, thus reducing the total number of running
jobs. This ability is based on the number of resources (drives) available and the
setting for Number of Data Readers in the
Subclient Properties (General)
tab, which is the number of paths in the subclient that will run concurrently given
sufficient available resources.
This feature is useful only for a NAS client which has subclients with multiple
data content paths defined, or (for all NAS clients except Hitachi) specifies a
content path of "/" and has more then one volume
or root file system. If this is not true of a NAS subclient, then its backups will
not utilize multiple data streams.
How to configure Multiple Stream Backups for NAS data
The following section provides the steps for configuring Multiple Stream Backups:
- Create a new Subclient or configure
an existing one.
- In the Content
tab of the Subclient Properties assign multiple content paths to this subclient
(or if this subclient is to backup the entire NAS client) use the “\” content
- In the General
tab of the Subclient Properties, specify the Number of Data Readers,
i.e., the maximum number of backup threads that you would like to run concurrently.
- In the Storage
Device tab of the Subclient Properties, assign a Storage Policy with
a sufficient number of streams to meet the expected conditions.
- Run a backup. For instructions, see Backup
- NAS NDMP - How To.
- To confirm the backup job is using multiple streams, right click the job
in the Job Controller window, select Detail..., and in the Job Details
window select the
tab. Note that the actual number of streams shown will vary as the job progresses.
- The actual number of concurrent backup streams employed during a backup
job is limited by the number of resources available to the Storage Policy, whether
other subclients are also using the same Storage Policy, number of remaining
subclient content paths that have not finished being backed up, and the Number
Of Data Readers value specified for this subclient.
- After a given subclient content path has been backed up (for a particular
thread) the backup of the next subclient content path will begin, until a backup
thread has been started for each subclient content path.
- If the number of available resources for a storage policy is the limiting
factor for a multiple stream backup job, it will use all of the resources that
are available, rather than fail or wait until more resources become available.
However, the number of streams used for the job will not increase when more
streams become available. Thus, for example, if a Storage Policy has a specified
Device Stream value of 5, and there are already 4 other jobs running, using
up 4 of the Device Streams, then the backup job will use the 1 remaining stream,
until the entire backup job completes.
- When multiple data streams are active, any action imposed on one stream
(such as suspending) will affect all streams.
Before performing any backup procedures for this agent, review the following
- For NetApp only, ensure that the NAS NDMP file server has NDMP turned on
before you begin performing backups The can be done by executing the command
ndmp on from the file server's console window.
- The backup size will never equal a sum of the file sizes in a NAS backup.
There is a backup header and file headers inserted into the backup file. Additionally,
Celerra has a minimum file size of 8k.
Filters can be used in conjunction with the "Items That Failed" list
on the data protection Job History Report to eliminate backup or archive failures by excluding
items which consistently fail that are not integral to the operation of the system or applications. Some
items fail because they are locked by the operating system or application and cannot be opened at the time of the data protection operation. This often occurs with certain system-related files and database application files.
Also, keep in mind that you will need to run a full backup after adding failed
files to the filter in order to remove them.
- For NetApp only, data verification can be performed for Read-Only
volumes when a writable location is specified on the file server with the
sDATAVERIFICATION_DESTINATIONDIR Registry key. This is useful if backing up a Snap mirror destination
volume to a tape drive on the file server.
- If you have installed NDMP
Remote Server (NRS) on your MediaAgent, and want to back up your data to
a library attached to the MediaAgent, be sure that the Storage Policy you select
for backups uses a drive pool configured to that MediaAgent.
- Deduplication is
supported when backing up data to magnetic libraries attached to a
MediaAgent. Backing up deduplicated data on EMC Celerra and NetApp filers requires
Remote Server (NRS) on your MediaAgent.
NAS NDMP Load-Balancing - The Drive Pools, Storage Policies, and Subclients for NAS NDMP can be configured so that backup, restore, and auxiliary copy
jobs will be spread among different MediaAgent, and thus the
processor load for these jobs will occur on different machines. For more
Subclients - NAS NDMP - Load-Balancing Considerations.
The number of tape drives in use on a particular NAS file server can be
limited through an option in
Media Management (Service Configuration) tab. This is useful since some
file servers have an upper limit to the number of concurrent backup or restore jobs
that can be run. The number entered with the Maximum allowed number of drive
reservations per NAS Filer option will limit the number of tape drives that
can be in use at a given time. For example, if five backup jobs were started
for a particular NAS file server, but the number specified with this option was
set to four, then the fifth job will be held in a waiting state until one of the
Incremental backups are supported on Hitachi clients and NetApp clients, with the following limitations:
- After a full backup, a maximum of 9 incremental backups can be run in a
row. At this point a full or differential backup must be run.
- After a differential backup is run, you can run another 8 incremental backups
before performing another full or differential backups.
- An incremental backup can be automatically converted to a full backup, when
required, through the use of the
registry key. You may wish to set the key to Y
if backups are generating this event nasBackup:
Exceeded maximum number of incremental backups. Must run full or
differential backup as opposed to failing the job. Only
if all the paths of the subclient content generate this event will a new
Full backup job be run.
- To perform a backup from a Snapshot (i.e., back up data from a read-only
copy of the current file system) for a Hitachi NAS NDMP client, the Snapshot
option must be enabled on the Hitachi NAS file server associated with this NAS
client and the Backup
from Snapshot option on the client's
Options (NAS Options) dialog must be configured to match how the file server
has been configured. For more information about the Hitachi NAS file server
snapshot settings, refer to Hitachi's documentation.
NAS NDMP Backup Archives Report
The NAS NDMP Backup Archives
Report provides information on data protection archive jobs based on the selected
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