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NetVault 13.0 - Administration Guide for Managed Service Providers

Introduction Getting started Configuring clients Managing catalog search Configuring storage devices
About storage devices SAN considerations Quest DR Series systems Quest QoreStor NetVault SmartDisk EMC Data Domain Systems Snapshot Array Manager Virtual Tape Libraries Virtual standalone drives Shared Virtual Tape Libraries Physical tape devices Storage tiers
Backing up data Managing policies Restoring data Managing NetVault dashboard Managing jobs Monitoring logs Managing storage devices
Role-based access to manage storage devices Monitoring device activity Managing disk-based storage devices in list view Managing disk-based storage devices in tree view Managing the Snapshot Array Manager Managing tape libraries in list view Managing tape libraries in tree view Managing tape drives in list view Managing tape drives in tree view Adding shared devices
Managing storage media Managing user and group accounts Managing Tenant Monitoring events and configuring notifications Reporting in NetVault Working with client clusters Configuring default settings for NetVault
About configuring default settings Configuring encryption settings Configuring plug-in options Configuring default settings for post-scripts Configuring default settings for Verify Plug-in Configuring Deployment Manager Settings Configuring Job Manager settings Configuring Logging Daemon settings Configuring Media Manager settings Configuring Network Manager settings Configuring Process Manager settings Configuring RAS device settings Configuring Schedule Manager settings Configuring Web Service settings Configuring Auditor Daemon settings Configuring firewall settings Configuring general settings Configuring security settings Synchronizing NetVault Time Configuring the reporting utility Configuring NetVault WebUI default settings Configuring NetVault to use a specific VSS provider Configuring default settings using Txtconfig
Diagnostic tracing Managing diagnostic data Using the deviceconfig utility NetVault processes Environment variables Network ports used by NetVault Troubleshooting
Common errors Safe Mode in NetVault

Viewing tape drive details

On the Manage Devices page, you can view the list of storage devices added to the NetVault Server.

Device is online and available for use.

Device is offline. NetVault is able to detect the device, but unable to access it for backup or restore jobs.

Device is unavailable. NetVault is unable to detect the device.

On the Tape Drive Management page, you can view the following information:
Drive Info: This area shows general information about the drive:
Name: Drive name.
Vendor: Vendor name.
Product: Product name.
Client: Client to which the device is attached.
Serial Number: Serial number of the drive.
Status: Online or offline.
Contents: Label of the tape loaded in the drive. If the drive does not contain any tape, the column shows “Unloaded.”
Offsite Location: Offsite location of the tape, if specified.
Library: Library name.
Bay: Drive bay number.
Block Size: Media block size.
Buffer Size: Transfer buffer size.
Activity: Idle or writing.
Statistics Info: This area displays the drive usage statistics:
Total Data Written: Total amount of data written using the drive.
Total Data Read: Total amount of data read using the drive.
Write Errors: Number of write errors reported.
Read Errors: Number of read errors reported.
Date Last Written: Date on which the last write operation was performed.
Date Last Read: Date on which the last read operation was performed.
Cleaning Info: This area displays the drive cleaning statistics:
Date Last Cleaned: Date on which the drive last cleaning operation was performed.
Time Since Last Cleaning: Time elapsed since the last automatic or manual cleaning operation.
Times Cleaned: Number of times the drive has been cleaned.
Transferred Since Last Clean: Amount of data read or written since the last cleaning operation.
Usage Since Last Clean: Duration of time the drive has been used for read or write operations since the last cleaning operation.
Soft Errors Since Last Clean: Number of read or write errors reported since the last cleaning operation.
Activity chart: This area shows the activity graph if the device is being used by a backup or restore job.
Job details: This area shows the following information for active jobs:
Rate: Data transfer rate.
Job Title: Name of the job.
Job ID: Job identification number.
Job Instance: Instance identification number.
Job Phase: Phase identification number (1 or 2).
To view the slot details, click the Slots link or the Manage Slots icon . On the Slot Browser page, you can view the following information:
Drives table: The Drives table lists all tape drives for the library. It shows the following information:
Status icon: Drive status icon.
Bay: Drive bay number.
Name: Drive name.
Status: Drive status (online or offline)
Activity: Idle or writing.
Contents: Label of the tape loaded in the drive. If the drive does not contain any tape, the column shows “Unloaded.”
Slots table: The Slots table lists all slots for the library. It shows the following information:
Slot: Slot number
Status: Tape is loaded or unloaded.
Barcode: Barcode of the tape in the slot.
Media: Media label of the tape in the slot.
Media Group: Media group label of the tape in the slot.
Space Available: Free space available in the tape.
Cleaning lives status icon: Displays the cleaning lives icon if the slot contains a cleaning tape. ) indicates 5 or more cleaning lives remaining, ) indicates 1-4 cleaning lives remaining, and ) indicates 0 cleaning lives remaining.
Cleaning Lives Left: Displays the number of cleaning lives left.

Configuring performance options for a tape drive

On the Tape Drive Management page, click Performance.
In the Drive Performance Options, configure the following settings.

Drive Block Size

This option specifies the block size used for read and write operations. The default value is 64KiB.

You can change the media block size in increments of 1KiB, but many devices only accept a value in the multiples of 4KiB or 32KiB.

Increasing the block size can reduce the number of times a backup needs to read data and write it to media. However, large media block sizes do not always imply an overall faster backup. The maximum block size is limited by several factors, such as the OS, SCSI adapter, drive make, drive model, and drive type.

On Linux and UNIX systems, you can increase the media block size for optimum performance.


On Windows, you might be required to change the registry setting MaximumSGList to use block sizes larger than 64KB. Before changing this setting, check that the SCSI bus is only used by the tape devices. If other devices also use the SCSI bus, this registry change might prevent them from working. If you want to apply these changes only to a specific channel on the HBA, consult the hardware vendor.

To change the registry setting on Windows, follow these steps:

Open the key [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Services\<HBA Vendor>\Parameters (where <HBA Name> is specific to your SCSI card — for example, QL2200 for a Qlogic 2200 card).
Create the Parameters key, if it is not present.
Under Parameters, create the Device key, if it is not present.
Under the Device key, add the DWORD registry value MaximumSGList, if it is not present.

Drive Transfer Buffer Size

The transfer buffer or the shared memory is allocated in blocks of 32KiB. The default value is 8193KiB. For more information about changing the default value, see Changing the default Drive Transfer Buffer Size option.

Increasing the transfer buffer size can improve backup performance. To calculate the buffer size, use the following formula:

(<Total number of buffers> x 32KiB) + 1 byte

On Linux and UNIX systems, you require sufficient RAM and large Shared Memory segment. Before increasing the transfer buffer size, check the following settings on these platforms:


The total allowed shared memory is determined by the formula SHMMAX * SHMSEG. These values are often limited by the ulimit setting, and the command ulimit -a can be used to view these system settings.

On Windows, you require at least 2GB RAM and large virtual memory. You might also have to change the MaximumSGlist setting on the SCSI card.

For examples, see the Optimal transfer buffer size.

Software Data Compression

To perform software compression, select this check box. The data is compressed when it is transferred to the device during backup.

Compression Threshold

The value set for this option determines the minimum level of compression that must be achieved when data is compressed during a backup. For example, if you set the value to 80 percent, one of the following occurs:

If you specify 80 percent, a file size of a 100MB must be <= 80MB after compression however, the file size can be >80MB (like 81MB, 82MB, etc.), as the compression is done at block level.

When the specified compression level is not achieved for any block, in that case NetVault backs up that block in its uncompressed form. Where, some blocks may be compressed and some blocks may remain in uncompressed form. Hence, in some case, the file size after compression can be greater than 80 percent.

The extent that data can be compressed depends on the data contents. Also the encrypted data cannot be compressed. With some files, compression may actually result in a file that is larger than the original uncompressed file.

Compression Data Blocks

Type or select the number of data blocks per compression unit. The default block size is 8KiB.

Click OK to save the settings and close the dialog box.

Optimal transfer buffer size

The following table provides examples of the optimal values that can be used for some drive types.

Fast Modern Tape Drives

For example, LTO series, SDLT, and SAIT

65537 (64MiB + 1KiB)

Medium Speed Tape Drives

For example, DLT8000, DLT7000, and AIT-3

32769 (32MiB + 1KiB)

Older Professional Tape Drives

For example, DLT2000, DLT4000, and AIT-2

16385 (16MiB + 1KiB)

Older Low Capacity Low-end Drives

For example, EXB-8505, AIT-1, and DAT

8193 (8MiB + 1KiB)

Checking the status of a tape drive

On the Tape Drive Management page, click Check, and then in the confirmation dialog box, click Check again.
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