puredisk best practices

Veritas NetBackup PureDisk™ Best Practices Guide

Windows, Linux, and UNIX

Release 6.5

Publication release 6.5, revision 1

Veritas NetBackup PureDisk Best Practices GuideCopyright © 2008 Symantec Corporation. All rights reserved.

PureDisk 6.5.0

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Contents

Chapter 1 OverviewAbout this manual ................................................................................................. 7

Chapter 2 Planning data selections and backupsPerform initial backups manually or with the wizard ..................................... 9Policy tuning .........................................................................................................10Make specific data selections when using snapshot support .......................10Excluding files from a data selection ................................................................10Simulating a traditional backup plan ...............................................................10

Creating data selection templates for daily, weekly, and monthly backups ..................................................................................................11

Applying data selection templates to the clients ....................................12Creating policies for daily, weekly, and monthly backups ....................13Creating data removal policies for daily, weekly, and monthly

backups ..................................................................................................15Creating policy escalation actions .............................................................18

Configuring users to run under the Backup Operator ...................................19

Chapter 3 Creating data removal policies for specific filesCreating data removal policies for specific types of files ..............................21

Chapter 4 Comprehensive policy schedulingScheduling backup, replication, and maintenance policies ..........................23

Chapter 5 Tuning PureDiskConfiguration parameters ..................................................................................27

FingerprintType ...................................................................................27Port .........................................................................................................27TCPKeepAlive .......................................................................................27TCPSendBufferSize ..............................................................................28TCPReceiveBufferSize .........................................................................28MaxTransferRate .................................................................................28ReadBufferSize .....................................................................................29WriteBufferSize ....................................................................................29

6 Contents

Chapter
1
Overview

This chapter contains the following topics:

■ “About this manual” on page 7

About this manualThe PureDisk Best Practices Guide includes information about how to employ PureDisk’s features so they interoperate effectively. This manual expands on the information that is included in the other PureDisk manuals. The complete PureDisk documentation set is as follows:

■ PureDisk Administrator's Guide

■ PureDisk Backup Operator's Guide

■ PureDisk Best Practices Guide

■ PureDisk Client Installation Guide

■ PureDisk Getting Started Guide

■ PureDisk Deduplication Option Guide

■ PureDisk Storage Pool Installation Guide

8 OverviewAbout this manual

Chapter
2
Planning data selections and backups

This chapter includes the following topics:

■ “Perform initial backups manually or with the wizard” on page 9

■ “Policy tuning” on page 10

■ “Make specific data selections when using snapshot support” on page 10

■ “Excluding files from a data selection” on page 10

■ “Simulating a traditional backup plan” on page 10

■ “Configuring users to run under the Backup Operator” on page 19

Perform initial backups manually or with the wizardPureDisk terminates a backup job if it does not complete in a reasonable amount of time, as follows:

■ For a manual backup job or restore job, PureDisk has a limit of seven days. If the job does not complete by then, PureDisk generates an error message. PureDisk terminates the job if it does not complete in 14 days.

■ For a restore job or a backup job that is run from a policy, PureDisk has a limit of six hours. If the job does not complete by then, PureDisk generates an error message. PureDisk terminates the job if it does not complete in five days.

For an initial backup, Symantec recommends that you run the job manually or from the backup wizard. For information on backups, timeouts, and how to enable timeout notifications, see the PureDisk Administrator’s Guide.

10 Planning data selections and backupsPolicy tuning

Policy tuningIf you have more than 200 clients, make sure that there are no more than 200 data selections included in one backup policy.

Make specific data selections when using snapshot support

Snapshot support enables PureDisk to back up those files that are open at the time the backup is performed. If you use snapshot support, make sure that your data selections are very specific. Preferably, specify your data selections on a per-drive basis.

For more information about how PureDisk uses snapshot support, see the PureDisk Backup Operator’s Guide.

Excluding files from a data selectionWhen you define a data selection, you can specify that the data selection back up entire directories but exclude certain types of files. When the backup runs, PureDisk performance for data selections with excluded files is the same as for data selections without excluded files.

However, you may perform a backup and later edit the data selection to exclude certain files. In that case, PureDisk processes the excluded files as if they had been deleted all at one time. This action slows down some of backup process and creates work for the next data removal policy. If you want to exclude files from a data selection that you backed up, perform the following procedure.

To exclude files from data selections after they have been backed up

1 Recreate the data selection.

2 Disable the schedules on the old data selection.

3 Delete the old data selection after the retention period that you defined in the data selection removal policy.

Simulating a traditional backup planTypical backup plans usually include daily, weekly, and monthly backups. Such plans usually include a policy for each backup interval. That policy specifies the data to back up, the system affected, and how long to retain the data. Because

11Planning data selections and backupsSimulating a traditional backup plan

these traditional plans write both the file content and the metadata to backup media, they usually consume large amounts of tape or disk media.

If you have several similar clients, you can create a traditional backup plan for these clients that employs PureDisk and its data deduplication technology. Unlike typical backup methods that consume large amounts of backup media, PureDisk uses its data deduplication technology to store file content only one time. When you run PureDisk backups at daily, weekly, and monthly intervals, you ensure that you have a record of the metadata at these intervals. In addition, PureDisk also backs up any file content that is new or changed since a previous backup was performed.

To implement this plan, create data selections for each of these intervals, apply them to clients, and create backup policies. To ensure that these backups are removed from the system after a suitable retention period, also create three data removal policies.

The procedures in the following sections describe how to create the policies that simulate this traditional approach to backing up clients:

■ “Creating data selection templates for daily, weekly, and monthly backups” on page 11

■ “Applying data selection templates to the clients” on page 12

■ “Creating policies for daily, weekly, and monthly backups” on page 13

■ “Creating data removal policies for daily, weekly, and monthly backups” on page 15

■ “Creating policy escalation actions” on page 18

Creating data selection templates for daily, weekly, and monthly backups

The following procedures explain how to create a template for daily backups and how to copy that template for weekly and monthly use.

To create a template for daily backups

1 Click the Data Selection Templates tab.

2 In the left pane, click Add Template.

3 Complete the dialog box to specify the files you want to back up.

For example, specify the following:

■ The name of the template. For example, specify Daily - My Documents backup or Daily - data backup.

■ The directories to include in the data selection and the directories to exclude from the data selection.

12 Planning data selections and backupsSimulating a traditional backup plan

■ The operating system.

For more information about how to complete this dialog box, see the PureDisk Backup Operator’s Guide.

4 Click Save.

To copy a daily-use template and modify it for weekly and monthly use

1 Click the Data Selection Templates tab.

2 In the middle pane, select the daily template that you created in the previous procedure.

3 In the left pane, click Copy Templates.

4 In the middle pane, click the name of the new copy.

5 In the left pane, click Edit Templates.

6 In the dialog box, change the name of the template.

For example, change the template name to Weekly - My Documents backup or Weekly - data backup.

Do not change either the inclusion rules or the exclusion rules.

7 Click Save.

8 Perform the preceding steps again to create a monthly template.

For example, change the template name to Monthly - My Documents backup.

Applying data selection templates to the clientsUse the following procedure to apply the daily, weekly, and monthly data selection templates. Apply all three templates to each client.

See “Creating data selection templates for daily, weekly, and monthly backups” on page 11.

To apply a template

1 Click the Data Management tab.

2 Expand the storage pool in the middle pane.

Expand the tree until you see the client or the group of clients to which you want to apply the template. For example, you can apply the template to all the clients in a department or to all the clients in a storage pool.

3 Click the client name, the department name, or the storage pool name.

If you want to apply the template to more than one client, click a department name or the storage pool name.


Tip: You may have several clients in a department, and you may have applied this template to some of the clients in a previous session. If you apply the template on the department level, it is faster than to apply the template on each client individually. PureDisk does not reapply the template on the older clients. However, when you apply the template on the department level, you do not need to select each new client individually and apply the template.

4 In the left tasks pane, click Apply Data Selection Template.

5 Select the template you want to apply.

6 Select Yes to use a global template, which is the default. If you use a global template, PureDisk propagates any data selection template changes that you may make to all clients that use the template.

7 Click Continue.

Wait until PureDisk applies the template before you move to the next step.

8 Click Close window.

Creating policies for daily, weekly, and monthly backupsThe following procedures show how to create a policy for daily backups and how to copy that policy for weekly and monthly use.

To create a policy for daily backups

1 Click the Workflows tab.

2 In the tree pane, click Backup Policies and select a policy type.

3 In the left tasks pane, click Create Policy.

4 Complete all the tabs in the policy creation dialog box.

For example, perform the following steps:

■ On the General tab, perform the following steps:

■ Type a name for the policy. For example, Daily backup.

■ Select Enabled.

■ On the Data Selections tab, perform the following steps:

■ Expand the tree until you see the client or the group of clients to which you want to apply the policy.

■ Select the client or the client group. For example, you can apply the policy to all the clients in a department or to all clients in a storage pool.


■ Use the Data selections based on template drop-down list to specify the name of the daily backup data selection.


■ On the Scheduling tab, select the following:

■ In the upper part of the tab, select Weekly schedule and specify a start time.

■ In the lower part of the tab, click in the boxes to select Monday, Tuesday, Wednesday, Thursday, and Friday.

■ On the Parameters tab, select parameters that are appropriate to this data selection for your site.

5 Click Save.

To copy a daily use backup policy and modify it for weekly use


2 In the middle pane, click the daily policy that you created in the previous procedure.

3 In the left pane, click Copy Policy.


5 In the left pane, click Edit Policy.

6 Edit the tabs in the dialog box.

Perform the following steps:

■ On the General tab, change the policy name. For example, change the policy name to Weekly backup.

■ On the Data Selections tab, use the Data selections based on template drop-down list to specify the name of the weekly backup data selection.


■ On the Scheduling tab, perform the following steps:

■ In the upper part of the tab, specify a start time and select Weekly schedule.

■ In the lower part of the tab, click in the boxes to select Saturday.


7 Click Save.


To copy a weekly use backup policy and modify it for monthly use


2 In the middle pane, click the weekly policy that you created in the previous procedure.




6 Edit the tabs in the dialog box.


■ On the General tab, change the policy name. For example, change the policy name to Monthly backup.




■ In the upper part of the tab, specify a start time and select Monthly schedule.

■ In the lower part of the tab, click in all boxes to select all months in the year.


7 Click Save.

Creating data removal policies for daily, weekly, and monthly backups

A data removal policy removes data from PureDisk storage if the data is no longer needed. The following procedures show how to create a removal policy to remove any unneeded data that was backed up in daily, weekly, and monthly backups.

■ On the Data Selections tab, you can specify to remove files in a particular data selection.

■ On the Metadata tab, you can specify to remove only specific files. PureDisk displays this tab only for Files and Folders or UNC Path backups.

To create a data removal policy for the daily backups



2 In the middle pane, click Data Management Polices > Data Removal.

3 In the tasks pane, click Create Policy.




■ Specify a name for the policy. For example, Daily backup - removal policy.

■ Select Enabled.


■ Expand the tree until you see the client or the group of clients to which you want to apply the policy.

■ Select the client or the client group. For example, you can apply the policy to all the clients in a department or to all clients in a storage pool.




■ In the upper part of the tab, specify a start time and select Weekly schedule.

■ In the lower part of the tab, click in the boxes to select Monday, Tuesday, Wednesday, Thursday, and Friday.

■ (Conditional) On the Metadata tab, you can specify to remove only specific files.


In Remove versions backed up, select Older than (in days) and specify 14 days.

5 Click Save.

To copy a daily data removal policy and modify it for weekly use


2 In the middle pane, click the daily data removal policy that you created in the previous procedure.

3 In the tasks pane, click Copy Policy.




6 Complete all the tabs in the dialog box.



■ Specify a name for the policy. For example, Weekly backup - removal policy.

■ Select Enabled.


■ Expand the tree.

■ Select the clients to which you want to apply this policy.




■ In the upper part of the tab, specify both a start time and the schedule. Specify a start time that is an hour or two later than the start time that you specified for the daily data removal policy. For the schedule, select Weekly schedule.

■ In the lower part of the tab, click in the box to select Saturday.



7 Click Save.

To copy a weekly data removal policy and modify it for monthly use


2 In the middle pane, click the weekly data removal policy that you created in the previous procedure.


4 In the tree pane, click the name of the new copy.


6 Complete all the tabs in the dialog box.




■ Specify a name for the policy. For example, Monthly backup - removal policy.

■ Select Enabled.


■ Expand the tree.

■ Select the clients to which you want to apply this policy.




■ In the upper part of the tab, specify both a start time and the schedule. Specify a start time that is an hour or two later than the start time you specified for the weekly data removal policy. For the schedule, select Monthly schedule.

■ In the lower part of the tab, click in all boxes to select all months in the year.

■ (Conditional) On the Metadata tab, you can specify to remove only specific files.



7 Click Save.

Creating policy escalation actionsYou can request that PureDisk notify you when a policy fails to run by creating a policy escalation action for each policy.

To create policy escalation actions

◆ Create policy escalation actions for the three backup policies and the three data removal policies that you created.

For information about how to create policy escalation actions, see the PureDisk Backup Operator’s Guide.

19Planning data selections and backupsConfiguring users to run under the Backup Operator

Configuring users to run under the Backup OperatorBy default, on Windows platforms, the PureDisk agent runs under LocalSystem. Configuring users to run under Backup Operator allows read permissions and permits PureDisk to read all of the ACL settings. The change also limits the user permissions that PureDisk allows for security purposes.

You are required to configure users and the PureDisk agent to run under Backup Operator when you back up mapped drives. You may also want to configure users and the agent to run under Backup Operator as part of your normal site procedures. For more information about how to configure users to run under the Backup Operator, see the PureDisk Backup Operator’s Guide.

20 Planning data selections and backupsConfiguring users to run under the Backup Operator

Chapter
3
Creating data removal policies for specific files


■ “Creating data removal policies for specific types of files” on page 21

Creating data removal policies for specific types of files

You may have your data selections that do not exclude certain types of files from backups, but which you later determine that you want to exclude. You can create one or more data removal policies to remove these files from PureDisk storage later. For example, if you want to remove all files that end in .mp3 from your PureDisk storage, you can create a data removal policy to remove them.

■ On the Data Selections tab, you can specify to remove files in a particular data selection.

■ On the Metadata tab, you can specify to remove only specific files. PureDisk displays this tab only for Files and Folders or UNC Path backups.

To create a data removal policy for a specific type of file


2 In the tree pane, select Data Management Policies > Data Removal.

3 In the left pane, click Create Policy.




■ Specify a name for the policy. For example, Removing MP3 files.

22 Creating data removal policies for specific filesCreating data removal policies for specific types of files

■ Select Enabled.

■ On the Data Selections tab, select Include all data selections selected above.

■ On the Scheduling tab, specify a schedule.

■ (Conditional) On the Metadata tab, click Add. Fill in the following fields in the dialog box to describe the files you want to remove:

■ For Rule name, specify a name for this filter. For example, MP3 Files.

■ For Folder name, specify an asterisk (*).

■ For File name, specify *.mp3.

5 Click OK.

6 Click Save.

Chapter
4
Comprehensive policy scheduling


■ “Scheduling backup, replication, and maintenance policies” on page 23

Scheduling backup, replication, and maintenance policies

PureDisk enables you to create several policies for backups, replication, and other activities. For example, you can create your own policies for backups, garbage collection, and other tasks.

If you have more than 200 clients, make sure that no more than 200 jobs start at the same time. More than one job can run at the same time, but schedule a 10-minute interval between the start times of each job.

PureDisk includes some system policies and some default policies, many of which are for maintenance.

Table 4-1 on page 23 explains how to use and run various PureDisk policies.

Table 4-1 PureDisk recommended practices for policies and scripts

Policy Default Recommended frequency Notes

Backup policies No default Run backup policies on work days when system activity is high.

Schedule the backup policies to run when system activity is low, for example, at night between 8pm and 8am.

For example, configure the backup window in the Parameters tab for 8pm through 8am.

24 Comprehensive policy schedulingScheduling backup, replication, and maintenance policies

Data Removal policy

No default Run a removal policy one, two, or three times a week and when few backup policies run.

Configure this policy right after you deploy a storage pool. Do not wait for content routers to fill with unneeded backups.

The more frequently you run a data removal policy, the less time each run takes because less data is removed in each run.

If you cannot schedule frequent data removal policy runs, run the data removal policy one time a week, on the weekend. If you schedule this policy to run less frequently, you risk overloading the system when it runs.

Replication policy

No default Daily. Schedule replication policies to run right after your backups complete.

You can implement replication as additional disaster recovery support.

CR Garbage

Collection

policy

Monthly Monthly. Run the policy at least one time a month.

Data Selection

Removal policyNo default Run as needed. Run the policy when you delete a whole

data selection on a client.

Disaster

Recovery

Backup policy

No default Daily. This policy consumes a lot of system resources, and Web UI performance can be slower.

Run the policy when no backups run and when you do not perform system maintenance tasks.

Table 4-1 PureDisk recommended practices for policies and scripts (Continued)


25Comprehensive policy schedulingScheduling backup, replication, and maintenance policies

MB Garbage

Collection

policy

Monthly One to three times each week. Check Log deleted records if you want to create a log of deleted records in the job log of the metabase garbage collection policy.

If you check Enable extensive cleanup, be aware that this method consumes many system resources. Enable this option on an infrequent basis, for example one time every three months. You can copy the default policy and enable this capability only in a policy that runs every three months.

Maintenance policy

Saturday morning

Weekly. Performs agent maintenance. Cleans up log files and temporary files on the client and cleans up events from agents in the storage pool authority database.

By default, the Parameters tab specifies to remove jobs and events that are older than 14 days. In addition, it removes temporary files that are older than 7 days. If you want to keep this information for longer, change this parameter.

Do not disable this policy. Make sure this policy runs regularly.

Content router

queue

processing

policy

No default Four times each day.

Schedule this policy to run outside your file backup and disaster recovery backup windows.

Performs content router queue maintenance.

Do not disable this policy. Make sure this policy runs regularly.



26 Comprehensive policy schedulingScheduling backup, replication, and maintenance policies

Server

Maintenance policy

Daily Daily. Performs server agent maintenance on the PureDisk nodes. It removes unreferenced (unneeded) data from the databases.

PureDisk has a default server maintenance policy, and you can add additional server maintenance policies. For example, you can create the following policies:

■ Create a server maintenance policy to clean up only the content router database. Run this policy one time every two weeks.

■ Create a second server maintenance policy to clean up only the metabase engine database. Run this policy every week.

■ Create a third server maintenance policy to clean up the storage pool authority database. Run this policy one time a month.

You can delete this policy, but Symantec does not recommend deletion.



Chapter
5
Tuning PureDisk

This chapter describes some PureDisk configuration parameters that you can modify.

Be sure to review the chapter in the PureDisk Administrator’s Guide on how to reconfigure your environment before you make changes. It has procedures for editing and pushing configuration changes.

Configuration parameters

FingerprintTypeThis parameter determines the fingerprinting algorithm to be used. Type 0 is the old algorithm without fingerprint collision detection and type 1 is for PureDisk release 6.5 with fingerprint collision detection. This value is set during agent installation and should not be changed.

PortThis parameter determines the port on which the content routers listen for incoming connections. If you change this parameter, you must enter the same number in the configuration file of all content routers and all agents. Symantec recommends that you leave this parameter unchanged.

TCPKeepAliveThis parameter determines whether or not TCP keep-alive probes are to be sent during connection idle time. It allows an agent to detect if an existing connection with a content router is still valid.

For more information regarding this topic, search Google on the Web for SO_KEEPALIVE and TCP_KEEPALIVE or visit the Web pages listed in the TCPSendBufferSize parameter.

28 Tuning PureDiskConfiguration parameters

TCPSendBufferSizeThis parameter sets the maximum socket send buffer size in bytes. If you increase this value, the agent can transmit more data before the backup blocks. The backup blocks while it waits for more buffer space to become available, which happens after PureDisk sends the currently buffered data to the content router. The default value is operating-system dependent and for UNIX, usually depends on other kernel configuration settings. Search Google for SO_SNDBUF for more information on this subject.

On high-latency lines (or high bandwidth lines), it is definitely worthwhile to experiment with various values for the send buffer size. For optimal behavior, the TCPReceiveBufferSize buffer size should be adjusted as well.

A general formula for establishing an initial value for this parameter in kilobytes is as follows:

size = b * d * 10^3 / 8

The formula assumes a delay d in microseconds and a bandwidth b in Kbytes/sec. You can measure the delay in microseconds by using the ping command)

If you have a 45M-bit line and a 30-ms delay, the optimal send buffer size would be 165Kbytes.

http://dast.nlanr.net/Guides/GettingStarted/TCP_window_size.

html has additional information on this subject, and http://www.die.net/doc/linux/man/man7/tcp.7.html describes the various kernel configuration parameters in detail.

If you specify a value of 0, it enables the operating system default.

TCPReceiveBufferSizeThis parameter sets the maximum socket receive buffer size, in bytes. If you increase this value, it may reduce the number of disk writes that the agent must perform during a restore. Using a small value has a negative impact on performance. The default value is operating-system dependent and for UNIX, usually depends on other kernel configuration settings. Search Google for SO_RCVBUF for more information on this subject.

If you specify a value of 0, it enables the operating system default.

MaxTransferRateThis parameter specifies, in Kbytes/sec, the maximum throughput on a connection with a content router (with a variance of about 10%). A value of 0 means no bandwidth limit is applied.

29Tuning PureDiskConfiguration parameters

You may want to specify a bandwidth limit in the following situations:

■ Slow connections (T1 or so)

■ Connections that are shared by other services

■ If backups take place during the day

If you specify a bandwidth limit, it increases the backup and restore duration.

ReadBufferSizeThis parameter specifies, in bytes, the maximum amount of data that can be read from disk in a single read operation. The default value is 64kbytes, which corresponds to the default TCPSendBufferSize on most operating systems.

If a backup consists mainly of large files a higher value could improve performance slightly. If you specify a lower value, it has a negative impact on performance because PureDisk requires more read operations to process a file.

An optimal value is not easy to establish; it requires experimentation with different values. If you specify large values, it may have an adverse effect on performance because it may defeat the read-ahead capabilities of the operating system or underlying hardware.

Initially, the following values may be used:

For an average file size < 128KB use the default setting

For an average file size < 64MB use 128kb

For an average file size < 128MB use 256kb

For an average file size> 128MB use 512kb

No direct link exists between this configuration parameter and the TCPSendBufferSize parameter. However, there is an indirect connection between the two parameters. The TCP buffer configuration directives let you specify settings to result in optimal network throughput. The Read (and Write) buffer directives let you specify settings to achieve optimal disk throughput.

There also exists an indirect link with the specified segment size: the agent needs to buffer data until it has a full segment available so that it can compute the segment fingerprint. To some degree, the rules that are given here use this link.

Note: If you specify a higher value, more memory is used during backup.

WriteBufferSizeThis parameter specifies, in bytes, the maximum amount of the data the agent may buffer during a restore before writing it to disk. The default value is 32k

30 Tuning PureDiskConfiguration parameters

bytes, which corresponds to the default TCPReceiveBufferSize setting on most operating systems.

If you specify a higher value, it may increase the number of disk writes. However, a higher value might increase the I/O wait time (that is, the time the application is blocked while waiting for the I/O to complete). If you specify a low value, it has a negative impact on performance.

An optimal value is not easy to establish; it requires experimentation with different values. The following information may be helpful:

During restore, the content router streams the segment data to the agent. While the agent receives the data, it passes it through the decryption/decompression layer, which places the result in the write buffer. After this buffer is full, it is written to disk.

The value for WriteBufferSize may be set equal to the TCPReceiveBufferSize but it should never be set to a value larger than the segment size.

Index

Bbackup

implementing a traditional backup plan 10initial 9policy recommendations 23PureDisk timeouts 9snapshot support 10

best practices 9, 21, 23, 27

Ccontent router queue processing

recommendations 25

Ddata deduplication 11data reduction factor, see data deduplicationdata removal policy

for specific file types 21recommendations 24

data selectionexcluding files after a backup 10removal policy recommendations 24

disaster recoverypolicy recommendations 24

Ggarbage collection

policy recommendations 25

Mmaintenance


Rreplication


32Index