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Solstice Backup 5.1 Administration Guide

Chapter 10 Silo Support Module

This chapter describes the Silo Support Module that you can use with Backup Server Edition, Backup NetWork Edition or Backup Power Edition. It also provides information about how to enable and use a silo with Backup.

The following topics are addressed in this chapter:

Overview

A silo is a peripheral machine that typically contains many storage devices. Silos are controlled by silo management software, which is provided by the silo vendor and installed on a server. The silo server cannot be the same machine as the Backup server.

The silo and devices in the silo can be shared among many applications, systems, and platforms. Like autochangers, silos make data and media operations more automatic. Silos can load, change, and manage volumes and clean the devices automatically.

How Backup Interacts With a Silo

A Backup server or storage node acts as a client of the silo management software. Backup communicates with the silo through the Silo Tape Library Interface (STLI) library.

To access the volumes and devices in a silo, Backup sends a request to the silo management software, in the form of an STLI library call. For example, to mount a volume in a silo device, the Backup daemon sends a request to the silo management software to mount the volume into a particular device in the silo. The silo server responds to the request and mounts the volume in the silo. For further details on this process, refer to the stli man page.

The silo management software controls many of the operations that Backup controls with an autochanger. For example, the silo management software keeps track of the slot where each silo volume resides and usually also controls the deposit and withdrawal of volumes and automated cleaning of silo devices.

Silo Installation and Configuration

The following sections explain how to install and configure a silo for use with Backup.

How to Install a Silo with Backup

  1. Install the silo management software on the silo server.

    On the following models, all the necessary software was installed when you installed Backup. Skip to Step 4 if your model is listed below:

    • StorageTek on Solaris, AIX, and HP-UX

    • EMASS/Grau on Solaris, AIX, HP-UX, and Windows NT

    • IBM 3494 on Solaris and AIX

  2. If your silo model does not appear in the list above, install the STLI library on the Backup server or storage node that uses the silo.

    Follow the instructions provided by the silo vendor.

  3. Ensure that the Backup server or storage node is properly connected to the media devices in the silo that Backup uses.

  4. Run the jb_config program to configure the devices in the silo for Backup to use.

    See "How to Configure a Silo" for instructions.

  5. Enable the Silo Support Module using the instructions on your Silo Support Module enabler certificate.

  6. Register and authorize the Silo Support Module.

    See "How to Register and Authorize Your Software " for instructions.

How to Configure a Silo

Use the jb_config program to configure the silo. The program prompts you to enter the following information:

For each device you configure, the program prompts you for the following information:

Example: Configuring a Silo

The following example was created on a Backup server for Solaris. The output of the jb_config program varies slightly, depending on the operating system and the type of silo.


# jb_config
         1) Install an Autodetected SCSI Jukebox.
         2) Install a Serial Jukebox.
         3) Install an SJI Jukebox.
         4) Install an RLM Jukebox
         5) Install an STL Silo.

What kind of Jukebox are you installing? [1] 5
Supported Silo types for this system are:

        1) ACSLS Silo							(StorageTek)
        2) DAS Silo							(Emass/Grau)
        3) 3494 Silo							(IBM)

Enter the number corresponding to the type of silo you are
installing:
Choice? 1
Installing a StorageTek Silo.
Name you would like to assign to the Silo device? stk_silo
Name of the host running the ACSLS software? [] expo1
Pathname of the STL library for the ACSLS silo?
[/usr/lib/nsr/libstlstk.so] [Return]
Do you want automated device cleaning support enabled? (yes/no) n

How many devices are to be configured for this silo (1 to 64)? [4] 1
Enter pathname of media drive 1: ? /dev/rmt/0mbn
This media device has not been configured yet. Please select a
media device type for /dev/rmt/0mbn.
                a) himt
                b) qic
                c) 4mm
                d) 8mm
                e) 8mm 5GB
                f) 3480
                g) dlt
                h) optical
Choice? h
Enter corresponding silo name of media drive 1: ? 0,0,2,0
Since this is a silo, the barcode reader is enabled, and volume
labels are set to match barcode labels
Jukebox has been added successfully

You can view the results of your silo configuration in the Jukeboxes resource in the Backup administration program (nwadmin) or in the nsradmin program. Refer to the online help or the nsr_jukebox man page for details on the attributes in the Jukeboxes resource.

Silo Device-Naming Conventions

The jb_config program prompts you for the silo name of the storage devices, the name of a device in the silo. The silo name is the name that the Silo Management Software uses to refer to that device. Depending on the type of silo you have, the device name can take several forms. This section describes the naming conventions of the currently supported silos.

StorageTek

The Storage Tek (STK) silo management software, either a program called ACSLS that runs on a UNIX system or a program called Library Attach that runs on an MVS system, names devices according to a coordinate system based on the physical location of the devices in the silo.

For tape drives, the name consists of four digits separated by commas. The first digit refers to the automated cartridge system (ACS) with which the drive is associated. The second digit refers to the library storage module (LSM) in which the drive is located. The third and fourth digits refer to the panel and slot location in which the drive is located. A typical name for an STK drive looks like 1,0,1,0.

Ask the silo administrator the drive names for the devices that Backup can use. There is no method to find this information from the Backup system. To connect to more than one drive, find out the SCSI IDs for each drive and properly match the IDs to the silo names. If you accidentally swap operating system device names and silo names, you can only mount and unmount volumes; you cannot read or write to the volumes after they are mounted. To reconfigure the device names properly, use the Backup administration program to change the order of the device names in the STL Device Names attribute of the Jukeboxes resource.

IBM 3494

The silo management software for the IBM 3494 names devices with an eight-digit number to identify the 3590 drives in the silo. Use the IBM supplied mtlib command to determine the names of all the devices in the 3494:


# mtlib -l library-name -D

Either ask the silo administrator which device is reserved for Backup, or test to decide which silo drive name matches with each Solaris device name.

EMASS/Grau

The silo management software for the EMASS (in North America) or Grau silos is a program called DAS. DAS acts as a front end for the silo control program called AMU. When the silo is configured, the silo administrator gives each drive a symbolic name. The symbolic name can be any alphanumeric string.

To set up DAS to work with Backup, follow these steps:

  1. Ask the silo administrator to configure DAS to accept commands from your Backup server or storage node machine.

  2. Ask the silo administrator to either:

    • Use the dasadmin allocd command to allocate one or more devices to the Backup server or storage node

    • Configure your Backup server or storage node as an administrator, so you can enter the dasadmin allocd command to allocate devices from your Backup server or storage node machine

To find the names assigned to the devices in the silo, you can use a utility called dasadmin.

  1. Set the following environment variables:

    • DAS_SERVER, the hostname of the silo management server, which runs DAS

    • DAS_CLIENT, the hostname of the Backup server or storage node

    • ACI_MEDIA_TYPE, one of: 3480, CD_THICK, CD_THIN, DECDLT, 8MM, 4MM, D2, VHS, 3590, CD, TRAVAN, DTF, BETACAM, AUDIO_TAPE and DAS_MEDIUM, same value as ACI_MEDIA_TYPE

  2. Issue the following command to see a list of drives and the hostnames to which they are allocated: 


dasadmin ld

Media Management in a Silo

Because more than one software application can use a silo, media management in a silo requires extra operations to protect the volumes used by other programs from being overwritten by Backup.

The tasks described in this section deal with how volumes are specified for Backup to use, how volumes are mounted in the devices, and how volumes are identified and counted in the silo.

What Slot Numbers Mean in a Silo

In an autochanger, Backup specifies many of the functions by a slot number; silos use this same idea. In an autochanger, there is a fixed number of slots; Backup uses the slot number to refer to the physical location of a volume. However, a silo has a variable number of slots, starting at zero when you first configure it and limited by the silo license you purchased. The fundamental identifier of a silo volume is its barcode, which is often called a "volser" in silo documentation. The volser never changes over the life of a particular volume.

When the nsrjb command displays a list of the contents of a silo, it also displays a slot number. You can use the slot number to specify which volumes to mount, unmount, label, and inventory. Volumes are not always assigned the same slot number in the silo. The slot numbers in the silo are assigned dynamically, based on the sorted order of the barcodes that have been allocated. If you allocate more barcodes that fall earlier in the sort sequence, the slot numbers of all the volumes later in the sequence change.

Because the slot number is not a perfect identifier for silo volume, operations that might change the slot number cannot accept a slot number as arguments. For example, you cannot deallocate volumes based on slot numbers, because this operation can change the slot numbers of volumes being deallocated.

Using the CAP to Deposit and Withdraw Volumes in a Silo

A Cartridge Access Port (CAP) enables you to deposit and withdraw volumes in a silo without opening the door to the silo. The CAP is useful because you can add (deposit) and remove (withdraw) volumes in a silo without having to reinventory the entire silo. When you use the CAP to add or remove volumes, Backup does not automatically take inventory, read barcode labels, or locate empty slots in the silo. Use the silo inventory feature and Jukeboxes resource for these tasks.

You can use Backup commands or the silo management software to control the CAP on the currently supported silos to deposit and withdraw volumes in a silo. It is often more efficient to use the silo management software, especially to deposit or withdraw a large number of volumes.

The Backup command to allocate and deposit volumes is: The Backup command to deallocate and withdraw volumes is:


# nsrjb -a -Txxxx -d 


# nsrjb -x -Txxxx -w

The deposit and withdraw functions are not available in the Backup administration program GUI.

On some silos (IBM 3494 and StorageTek silos when the CAP is set to automatic mode), the silo management software inserts volumes automatically. You cannot use Backup to insert volumes.

On StorageTek silos, due to differences between the internal operations of Backup and the StorageTek silo management software, Backup can only withdraw one volume at a time. You must physically remove the volume from the silo's CAP before you can withdraw any more volumes. On EMASS/Grau silos, Backup can control both the deposit and withdraw functions.

How to Allocate Volumes in a Silo

When you allocate volumes, you tell Backup which volumes it can use. Because more than one software application can use a silo, it is possible that a different application could read or write to volumes that belong to Backup. To prevent this problem, most silo management programs include methods of limiting access to volumes based on the hostname of the machine on which Backup and the other programs run. Backup does not provide any method for setting up this sort of protection; it must be configured by the silo management program.

When you allocate a volume, Backup queries the silo management software to verify that the volume you requested exists. If the volume exists, the volume is allocated to Backup. If the volume does not exist, the following message is displayed:


barcode xxxxxx is not present in the silo and was not added

If you are allocating a range of volumes, the allocation continues after displaying the message. The message is informational and does not indicate a Backup error.

To allocate a silo volume, use either:

To deposit volumes into a silo and then allocate them (on silos that require manual depositing, such as EMASS/Grau), place the volumes in the insert area, then issue the following command:


# nsrjb -a -Txxxx -d

On StorageTek and IBM silos, the silo management software deposits volumes automatically.

Mounting and Unmounting Volumes in a Silo

You must mount a volume before you read or write data on it. Volumes are mounted in a device in the silo by the robotic mechanism.

To mount a volume in a silo device, you can use either the Backup administration program or the nsrjb -l command. When you mount a volume, you must specify the volume, slot, or barcode.

You must dismount a volume before you can inventory the volumes in a silo or deallocate the volume from a Backup silo. To unmount a volume, you can use either the Backup administration program or the nsrjb -u command.

To specify a barcode identifier or template for the volumes, you can use the -T option with either nsrjb command.

Labeling Volumes in a Silo

Labels tell Backup the pool to which the volume belongs and what type of data the volume should contain. (For more information on volume labels, see "Labeling Storage Volumes ".) Backup cannot write data to a volume until you label the volume.

To label a volume in a silo, use either the Backup administration program or the nsrjb -L command.

Backup labels for volumes in a silo include both a regular Backup volume label (written on the media of the volume) and a silo barcode identifier. The volume label is usually based on the volume pool's label template. The barcode identifier is written on a physical label on the outside of the volume, which the barcode reader in the silo can scan during inventory.

By default, the use of barcodes and matching barcode labels and Backup volume labels are both enabled for a silo. You can change the Match Barcode Labels attribute, but do not set the Barcode Reader attribute to No. When you set the Match Barcode Labels attribute and the Barcode Reader attribute to Yes, the internal volume label Backup writes on the media of each volume matches the barcode label on the outside of the volume. When the labels match, it is easier to track volumes, but Backup does not require the internal and external labels to match.

With most silo management software, you can use unlabeled volumes. The management software assigns a "virtual" barcode label to those volumes. Although you can use volumes without barcodes, it is very difficult to maintain integrity. This is because after you remove the volume from the silo, the information about the virtual barcode is lost. You can reinsert any volume without a barcode into the silo under a virtual barcode that Backup (or another application) associates with some of your data.

Deallocating Volumes in a Silo

If you no longer need a volume in a silo for Backup, you can deallocate the volume. Deallocation is basically the same operation as removing a volume from an autochanger. Although the robotic mechanism cannot load the volume, the entries in the Backup media database remain intact. If you allocate the volume again later, Backup can retrieve the data from it.

Use deallocation when your silo license limits the number of slots you can use or when you move data offsite for safer storage. In the case where the license limits the number of slots, you might be able to leave the volumes in the silo, so you can easily reallocate the volumes when you need to access the data on them.

The allocation operation is not automatic. You must manually allocate the volumes again and reinventory them to let Backup access the data. In the case of removing the volume from the silo for off-site storage, you can either deallocate it with Backup and then use the silo management software to eject it from the silo, or you can perform both operations at the same time from the command line with the nsrjb -x -Txxxx -w command.

Caution - Caution -

STK silos currently can only eject one volume at a time. The silo operator must remove each volume before another nsrjb -x -w command can be issued. If you deallocate and withdraw multiple volumes, they are all deallocated, but only the first is ejected. This limitation does not exist on EMASS/Grau or IBM 3494 silos.

How to Deallocate a Silo Volume

  1. Unmount the volume from the device.

  2. Use either the Backup administration program or the nsrjb -x -T barcode command to deallocate the volume.

    Refer to the online help for information about how to deallocate a silo volume using the Backup administration program. Refer to the nsrjb man page for further information on the nsrjb command. Refer to the stli man page for the correct format of barcode templates.

Taking a Silo Inventory

Take inventory of the volumes in a silo to make sure that the mapping between slot number and volume name is correct or to reconcile the volumes in a silo with the list of volumes in the Backup media database.

The slot number of a silo volume is not a numbered slot inside the silo, as it is in an autochanger. The slot number of a silo volume is the number of the volume's position in the list of volumes in a silo. You can view the slot number for each silo volume in the Backup administration program in the Jukebox Mounting dialog box.

Use the Backup administration program or enter the nsrjb-I command to inventory a silo. Backup examines all the volumes in the silo and compares the new list of volumes to the Backup media database. Then Backup produces a message listing any volumes located in the silo but not in the media database.

When Backup inventories a silo, the silo's barcode label reader reads the barcode labels on the outside of each volume. When a barcode matches an entry in the Backup media database, Backup does not need to load the volume into the device and read, and the inventory proceeds very rapidly. However, if Backup reads a barcode that does not match any of the entries in the media database, the volume must be mounted and read for a proper inventory.

You can inventory a range of slots or barcode labels if you are pressed for time and do not want to inventory all the volumes in your silo.

Silo Device Management

You can use the Backup administration program or the nsradmin program to do many of the device management tasks. For some tasks, you must enter a command at the system prompt.

Defining a Silo Device

If you add a new device to the silo and you want Backup to recognize and use the device, you can use one of two methods to reconfigure your silo to access the new device.

How to Define a Silo Device (jbconfig)

  1. Become root on the Backup server or storage node machine that uses the silo.

  2. Delete the silo definition.

    Use either the Backup administration program or the nsradmin program.

  3. Run the jb_config program to reconfigure the silo.

    Use the same name for the silo as before, and add the additional device.

How to Define a Silo Device (nsradmin -c)

  1. Become root on the Backup server or storage node machine that uses the silo.

  2. Enter nsradmin -c (visual mode) to edit the silo definition.

    1. Select Dynamic and Hidden from the Options menu.

    2. Select nsr jukebox.

    3. Select Edit.

  3. Add the new device name to the Devices attribute.

    You must enter a comma between the device names.

  4. In the Number Devices attribute, increase the number of devices by one.

  5. Add a null string with comma to each of the following attributes, before the final semi-colon (,""):

    1. Loaded Volumes

    2. Loaded Barcodes

    3. Loaded Slots

  6. Add the name of the new device in the STL Device Names attribute.

    Surround the device name with quotation marks.

  7. Add the following entry to the Allocated Devices attribute:


    ,No

Example: Defining a Silo Device

The following examples show selected nsradmin attributes before and after you add a device.

Before:


devices: /op1;
number devices: 1;
allocated devices: No;
loaded volumes: "";
loaded bar codes: "";
loaded slots: "";
STL device names: "0,0,2,0";

After:


devices: /op1, /op2;
number devices: 2;
allocated devices: No, No;
loaded volumes: "", "";
loaded bar codes: "", "";
loaded slots: "", "";
STL device names: "0,0,2,0", "0,0,2,1";

If you define multiple devices in a silo for Backup to use, you do not need to specify them in any particular order in the Jukeboxes resource. The only restriction is that the list of device names in the Devices attribute must be in the correct order with respect to the list in the STL Device Names attribute.

Shared Devices

The basic elements of device sharing have been implemented in Backup. However, due to current limitations in the SCSI hardware on Backup platforms, none of the device-sharing functions have been implemented. If you issue device reservation commands there are no errors, but the devices are not reserved. The STL Device Sharing and STL Device Reservation attributes in the Backup administration program and nsradmin have no effect on the behavior of Backup.

Device Cleaning

Do not enable automated cleaning for the silo in Backup. Refer to the documentation for your silo management software to find out how to clean devices in your silo. You cannot use the Backup automated device cleaning in a silo because it depends on fixed slot numbers.