C H A P T E R 6

Recycling

Recycling is the process of reclaiming space on archive volumes. The recycler works with the archiver to reclaim the space occupied by unused archive copies. As users modify files, the archive copies associated with the old versions can be purged from the system. The recycler identifies the volumes with the largest proportions of expired archive copies and directs the movement of unexpired copies to different volumes. If only expired copies exist on a given volume, a site-defined action is taken. For example, such a volume can be relabeled for immediate reuse or exported to offsite storage, thus keeping a separate historical record of file changes. Users are unaware of the recycling process as it relates to their data files.

This chapter describes the recycling process and directives. It includes the following topics:

Recycling Process Overview

Using Recycling Directives

Planning Recycling Operations

Recycling Process Overview

The recycler keeps the amount of space consumed by expired archive copies to a minimum as defined by site-specified parameters. At any time, the space on a given archive volume consists of the following:

Current data, consisting of archive images that are active currently.

Expired data, consisting of archive images that are no longer active currently.

Free space, consisting of space that is not being used by currently active or expired archive images.

The capacity of a volume is the total amount of space for data on a volume. For example, a 10-gigabyte tape volume with 3 gigabytes written to it has a capacity of 10 gigabytes and 7 gigabytes of free space.

New or newly labeled archive media starts out with all its capacity as free space. As data is archived to the media, the amount of free space decreases and the amount of current data increases.

As archived files in the file system are changed or removed, their archive images expire and they move from the current data classification to the expired data classification. The physical space used by these images remains the same; there is simply no longer a file in the file system pointing to that space. Only when space is recycled can these images be removed and the space they occupy become free. The goal of the recycler is to transform space used by expired data into free space without losing any current data.

You initiate recycling by entering the sam-recycler(1M) command either manually or through a cron(1) job. TABLE 6-1 shows recycling methods.

TABLE 6-1 Recycling Methods and Media Types
Recycling Method	Media and Notes
By automated library	Removable media cartridges. When you archive by library, you put recycling directives in the `recycler.cmd` file.
By archive set	Removable media cartridges and disk. When you archive by archive set, you put all recycling directives in the `archiver.cmd` file.

As TABLE 6-1 shows, you can recycle either by library or by archive set. If you are archiving to disk, you can recycle only by archive set.

The recycler and the archiver work together, as follows:

1. The recycler marks all the current (valid) archive images that are present on a volume with the rearchive attribute.

2. If you are archiving to removable media, the recycler marks the selected archive volume with the recycle attribute. This prevents the archiver from writing any more archive images to the volume.

3. The archiver moves all the marked images to another volume. This operation is called rearchiving. After the archiver moves the current archive images from the old volume to the new volume, the old volume contains only free space and expired space. If you are archiving to removable media cartridges, you can relabel and reuse the cartridge. If you are archiving to disk, the recycler removes the file that contains the expired archive images.

The recycler is designed to run periodically. It performs as much work as it can each time it is invoked. The recycler has to finish marking copies for rearchiving before the archiver can rearchive the files.

Sometimes expired archive images, with the rearchive attribute set, remain on media. This can happen under the following conditions:

The archiver does not run after the recycler marks expired archive images.

Media is not available for the archiver to use when moving the unexpired archive images.

There are miscellaneous archiver anomalies.

Between executions, the recycler keeps state information in the library catalogs and the inodes. During the recycling process, you can use the sls(1) command and its -D option to display information about a file. The output from the sls(1) command shows whether or not a file is scheduled for rearchiving.

Using Recycling Directives

The recycler.cmd file accepts the directives described in the following sections:

Specifying a Log File: The logfile Directive

Preventing Recycling: The no_recycle Directive

Specifying Recycling for an Entire Automated Library: The Library Directive

Specifying a Log File: The `logfile` Directive

The logfile directive specifies a recycler log file. This directive has the following format:

logfile = filename

For filename, specify the path to the log file.

The following is an example of a logfile= directive line:

logfile=/var/adm/recycler.log

Preventing Recycling: The `no_recycle` Directive

The no_recycle directive enables you to prevent recycling of volumes. To specify the VSNs, you use regular expressions and one or more specific media types.

This directive has the following format:

no_recycle media-type VSN-regexP [ VSN-regexP ... ]

TABLE 6-2 Arguments for the `no_recycle` Directive
Argument	Meaning
media-type	A media type from the `mcf`(4) man page.
VSN-regexp	One or more space-separated regular expressions to describe the volumes. For information, see the `regexp`(5) man page or see File Name search-criterion Using Pattern Matching: -name regex.

By specifying a media type, you can prevent the recycling of volumes stored on a particular type of media. One or more VSN-regexp specifications enable you to identify specific cartridges to be excluded from recycling.

For example, the following directive line excludes from recycling any tape volumes whose VSN identifiers begin with DLT:

no_recycle lt DLT.*

Specifying Recycling for an Entire Automated Library: The Library Directive

The library directive enables you to specify various recycling parameters for the VSNs associated with a specific library.

This directive has the following format:

library parameter [ parameter ... ]

For library, specify the library's name as specified in the family set field of the mcf(4) file.

For parameter, specify one or more space-separated parameter keywords from TABLE 6-3.

TABLE 6-3 Library Directive *parameter* Values
parameter Value	Meaning
`-dataquantity` size	Maximum amount of data that the recycler can schedule for rearchiving in its efforts to clear volumes of useful data. Default is 1 gigabyte.
`-hwm` percent	Library high water mark. Default is 95.
`-ignore`	Directive that prevents volumes in this library from being recycled. This directive is useful during testing of the `recycler.cmd` file.
`-mail` email-address	E-mail addresses to which recycling email messages are to be sent. By default, no email is sent.
`-mingain` value	Minimum VSN gain. Default is 50.
`-vsncount` count	Maximum number of recycled volumes to be counted. Default is 1.

For example, consider the following directive line:

gr47 -hwm 85 -ignore -mail root -mingain 40

It specifies the following for library gr47:

The library should be considered for recycling when the volumes in the library are 85 percent full.

The minimum percent gain is 40 percent.

Only one volume is to be recycled. This is also a default setting.

Recycling messages are emailed to root.

In addition, no more than 1 gigabyte is to be rearchived. This is the default, so it is not specified in the recycler.cmd file.

Planning Recycling Operations

Before configuring the recycler, note the following:

Directives in the archiver.cmd file control recycling by archive set. Directives in the recycler.cmd file control recycling by library. In addition, the recycler.cmd file controls general recycler behavior. For information on recycler directives, see Using Recycling Directives.

Do not recycle volumes that contain removable media files. You create removable media files by using the request(1) command. A volume with removable media files can never be drained.

Do not run the recycler while performing maintenance on a Sun StorEdge SAM-FS file system. The recycler uses the .inodes file and the mcf file to help identify files that are current or expired and the devices associated with a file system. Absence of proper information in these files can cause current archived data to appear as expired and be recycled.

All Sun StorEdge SAM-FS file systems must be mounted when the recycler is run. If you are recycling from online disk, the file system that contains the disk volumes must be mounted and the host system must be accessible.

The recycler is not enabled by default. You must initiate recycling by entering the sam-recycler(1M) command. When the recycler is initiated, the default recycler settings specified in Specifying Recycling for an Entire Automated Library: The Library Directive take effect. For more information on the recycler, see the sam-recycler(1M) man page.

Configuring the recycler involves the tasks described in the following sections, in this order:

1. Creating a recycler.cmd File

2. Editing the archiver.cmd File

3. Running the Recycler

4. Creating a crontab File for the Recycler

5. Removing -recycle_ignore and ignore Parameters

6. Creating a recycler.sh File

If you are archiving to cartridges in a library, this process involves creating a recycler.cmd file and, optionally, editing the archiver.cmd file. If you are archiving to disk, editing the archiver.cmd file.

The following procedures describe configuring the recycler for any archive media using the recycler.cmd and archiver.cmd files.

Creating a `recycler.cmd` File

Perform this step if you are recycling archive copies on cartridges in a library.

Note - Even if you are recycling by archive set, you still should configure each library in the recycler.cmd file. This ensures that VSNs that do not fall into an archive set can be recycled if needed.

The recycler.cmd file contains general recycling directives and can also contain directives for each library in the Sun StorEdge SAM-FS environment. A typical recycler.cmd file contains the following directive lines:

A logfile= directive line to specify a recycler log file. The system writes recycling messages and recycling reports to this file.

One or more directive lines for each library that contains volumes to be recycled. This line must contain the family set name (from the mcf file) for the library being recycled. This identifies the library to the recycler. For information on the recycling directive, see Using Recycling Directives.

Because you are creating the recycler.cmd line and it has not yet been tested, use the ignore keyword. You remove the ignore keyword in a later step in this process.

To create a recycler.cmd file, perform the following steps:

1. Become superuser.

2. Use vi(1) or another editor to open file /etc/opt/SUNWsamfs/recycler.cmd.

3. Add one or more directives described in this chapter to control recycler activity.

4. Save and close the file.

Alternatively, you can create a recycler.cmd file by using File System Manager software. For more information, see the File System Manager online help.

Example `recycler.cmd` File

CODE EXAMPLE 6-1 shows an example of a recycler.cmd file.

CODE EXAMPLE 6-1 Example `recycler.cmd` File
logfile = /usr/tmp/recycler.log stk30 -hwm 51 -mingain 60 -ignore -mail root

The following sections describe the parameters specified in CODE EXAMPLE 6-1.

The `-hwm 51` Parameter

By specifying a high water mark, you can set the percentage of media usage below which recycling cannot occur. This percentage is the ratio of the used space in the library to its total capacity. As an example, a library that holds ten 20-gigabyte tapes, three of them 100 percent full and the remaining seven each 30 percent full, has the following media utilization percentage:

((3* 1.00 + 7 * 0.30) * 20G ) / ( 10 * 20G ) * 100%= 51%

Note that this calculation does not distinguish between current data and expired data. It only addresses the amount of media used.

In this example, if the utilization percentage is 51 percent or less, the recycler does not automatically select any of the automated library's VSNs for recycling.

Note - You can force a VSN to be recycled by using the following command to set the recycling flag:

# chmed +c lt.VSN

When the +c flag is set, the archiver does not write any more archive images to the volume. The +c flag can be viewed through the samu(1M) utility. For more information, see the chmed(1M) and samu(1M) man pages. For information on using the samu(1M) operator utility, see the Sun StorEdge QFS Configuration and Administration Guide.

The `-mingain 60` Parameter

The minimum VSN gain percentage sets a lower limit on the amount of space to be gained by recycling a cartridge. For example, if a cartridge in an automated library is 95 percent current data and 5 percent expired data, the gain obtained by recycling the cartridge would be only 5 percent. It might not be worth moving the other 95 percent to retrieve this space. Setting the minimum gain to 6 percent or more inhibits the recycler from automatically selecting this VSN.

The `-ignore` Parameter

The -ignore parameter keeps the recycler from recycling a particular library. Use it when you are configuring the recycler.

The `-mail` Parameter

The -mail parameter specifies that the recycler send mail when recycling occurs on a given library. The mail message has the following subject line:

Robot robot-name recycle

TABLE 6-2 shows sample message bodies.

CODE EXAMPLE 6-2 Sample Recycling Messages
`I will recycle VSN` vsn`.` `Cannot find any candidate VSN in this media changer.` `Previously selected VSN` vsn `is not yet finished recycling.` `Previously selected VSN` vsn `is now finished recycling. It will now be post-recycled`.

CODE EXAMPLE 6-2 Sample Recycling Messages

I will recycle VSN vsn.

Cannot find any candidate VSN in this media changer.

Previously selected VSN vsn is not yet finished recycling.

Previously selected VSN vsn is now finished recycling. It will now be post-recycled.

Editing the `archiver.cmd` File

If you are archiving to disk, you must edit the archiver.cmd file in order to recycle.

If you are recycling by library, this step is optional.

To edit the archiver.cmd file, follow the steps described in To Create or Modify an archiver.cmd File and Propagate Your Changes.

Alternatively, you can edit the archiver.cmd file by using the File System Manager. For more information, see the File System Manager online help.

To enable recycling by archive set, you must add archive set recycling directives between the params and endparams directives. TABLE 6-4 shows the archive set recycling directives that you can use.

TABLE 6-4 Archive Set Recycling Directives
Directive	Function
`-recycle_dataquantity` size	Limits the amount of data that the recycler can schedule for rearchiving in its efforts to clear volumes of useful data.
`-recycle_hwm` percent	Sets the high water mark percentage.
`-recycle_ignore`	Prevents the archive set from being recycled.
`-recycle_mailaddr` mail-address	Sends recycler messages to the specified mail address.
`-recycle_mingain` percent	Limits recycling to VSNs that would increase their free space by at least the specified percentage.
`-recycle_vsncount` count	Limits the number of volumes to be rearchived to the specified value.
`-rearch_stage_copy` copy-number	Allows staging for rearchiving to take place from selected (faster) copies.

For more information about archiver directives, see Chapter 3 or see the archiver.cmd(4) man page.

Running the Recycler

1. Issue the sam-recycler(1M) command.

The recycler reads the recycler.cmd file.

2. Examine the standard output log, Sun StorEdge SAM-FS log, and /var/adm/messages for any error messages from the recycler.

Correct your files if errors appear.

CODE EXAMPLE 6-3 shows a sample recycler log file for recycling removable media cartridges.

CODE EXAMPLE 6-3 Recycler Log File Example for Removable Media Cartridges
========== Recycler begins at Wed Dec 12 14:05:21 2001 =========== Initial 2 catalogs: 0 Family: m160 Path: /var/opt/SUNWsamfs/catalog/m160 Vendor: ADIC Product: Scalar 100 SLOT ty capacity space vsn 0 at 25.0G 25.0G CLN005 1 at 48.5G 6.1G 000003 2 at 48.5G 32.1G 000004 3 at 48.5G 35.1G 000005 4 at 48.5G 44.6G 000044 5 at 48.5G 45.1G 000002 6 at 48.5G 45.9G 000033 7 at 48.5G 48.5G 000001 Total Capacity: 364.8G bytes, Total Space Available: 282.3G bytes Volume utilization 22%, high 95% VSN_min 50% Recycling is ignored on this robot. 1 Family: hy Path: /var/opt/SUNWsamfs/catalog/historian Vendor: Sun SAM-FS Product: Historian SLOT ty capacity space vsn (no VSNs in this media changer) Total Capacity: 0 bytes, Total Space Available: 0 bytes Volume utilization 0%, high 95% VSN_min 50% Recycling is ignored on this robot. 8 VSNs: ---Archives--- -----Percent----- m160 ----Status----- Count Bytes Use Obsolete Free Library:Type:VSN no-data VSN 0 0 0 87 13 m160:at:000003 no-data VSN 0 0 0 33 67 m160:at:000004 no-data VSN 0 0 0 27 73 m160:at:000005 no-data VSN 0 0 0 8 92 m160:at:000044 no-data VSN 0 0 0 7 93 m160:at:000002 no-data VSN 0 0 0 5 95 m160:at:000033 empty VSN 0 0 0 0 100 m160:at:CLN005 empty VSN 0 0 0 0 100 m160:at:000001 Recycler finished. ========== Recycler ends at Wed Dec 12 14:05:32 2001 ===========

CODE EXAMPLE 6-3 Recycler Log File Example for Removable Media Cartridges

========== Recycler begins at Wed Dec 12 14:05:21 2001 ===========

Initial 2 catalogs:

0  Family: m160                 Path: /var/opt/SUNWsamfs/catalog/m160

   Vendor: ADIC                 Product: Scalar 100

   SLOT                  ty    capacity         space vsn

      0                  at        25.0G        25.0G CLN005

      1                  at        48.5G         6.1G 000003

      2                  at        48.5G        32.1G 000004

      3                  at        48.5G        35.1G 000005

      4                  at        48.5G        44.6G 000044

      5                  at        48.5G        45.1G 000002

      6                  at        48.5G        45.9G 000033

      7                  at        48.5G        48.5G 000001

   Total Capacity:  364.8G bytes, Total Space Available: 282.3G bytes

   Volume utilization 22%, high 95% VSN_min 50%

   Recycling is ignored on this robot.

1  Family: hy                   Path: /var/opt/SUNWsamfs/catalog/historian

   Vendor: Sun SAM-FS           Product: Historian

   SLOT                  ty    capacity         space vsn

      (no VSNs in this media changer)

   Total Capacity:  0    bytes, Total Space Available: 0    bytes

   Volume utilization 0%, high 95% VSN_min 50%

   Recycling is ignored on this robot.

8 VSNs:

                    ---Archives---   -----Percent-----   m160

 ----Status-----    Count    Bytes   Use Obsolete Free   Library:Type:VSN

no-data VSN            0      0        0    87     13    m160:at:000003

no-data VSN            0      0        0    33     67    m160:at:000004

no-data VSN            0      0        0    27     73    m160:at:000005

no-data VSN            0      0        0     8     92    m160:at:000044

no-data VSN            0      0        0     7     93    m160:at:000002

no-data VSN            0      0        0     5     95    m160:at:000033

empty VSN              0      0        0     0    100    m160:at:CLN005

empty VSN              0      0        0     0    100    m160:at:000001

Recycler finished.

========== Recycler ends at Wed Dec 12 14:05:32 2001 ===========

CODE EXAMPLE 6-4 shows a sample recycler log file for recycling disk archive files.

CODE EXAMPLE 6-4 Recycler Log File Example for Disk Archive Files
---Archives--- -----Percent----- ----Status----- Count Bytes Use Obsolete Free Library:Type:VSN new candidate 0 0 0 41 59 <none>:dk:disk01 677 files recycled from VSN disk01 (mars:/sam4/copy1) 0 directories recycled from VSN disk01 (mars:/sam4/copy1)

CODE EXAMPLE 6-4 Recycler Log File Example for Disk Archive Files

---Archives---   -----Percent-----

 ----Status-----    Count    Bytes   Use Obsolete Free   Library:Type:VSN

new candidate          0      0        0    41     59  <none>:dk:disk01

677 files recycled from VSN disk01 (mars:/sam4/copy1)

0 directories recycled from VSN disk01 (mars:/sam4/copy1)

Creating a `crontab` File for the Recycler

If the system is performing as expected, you are ready to make a crontab entry for the superuser to run the recycler periodically, every two hours or more, depending on your site's conditions.

For instructions on creating a crontab entry, see the cron(1M) man page.

The following example entry in root's crontab file specifies that the cron daemon run the recycler every five minutes after the hour for every odd-numbered hour:

5 1,3,5,7,9,11,13,15,17,19,21,23   * * * /opt/SUNWsamfs/sbin/sam-recycler

Removing `-recycle_ignore` and `ignore` Parameters

As an alternative to the following procedure, you can use the File System Manager. For more information, see the File System Manager online help.

1. Use vi(1) or another editor to remove the -recycle_ignore parameters from the archiver.cmd file.

2. Use vi(1) or another editor to remove the ignore parameters from the recycler.cmd files.

You are now recycling.

Creating a `recycler.sh` File

Create a recycler.sh file if you are recycling archive copies on removable media cartridges. If you are archiving only to disk, do not perform this step.

The recycler executes the recycler.sh script when all the current images from a VSN have been rearchived to another VSN. You should determine your site requirements for dispensing with recycled cartridges. Some sites choose to relabel and reuse the cartridges; others choose to remove the cartridges from the automated library to use later for accessing historical files.

The recycler calls the /opt/SUNWsamfs/scripts/recycler.sh script with the following arguments:

Media type: $1  VSN: $2  Slot: $3  Eq: $4

For examples of the script, see the recycler.sh(1M) man page or /opt/SUNWsamfs/examples/recycler.sh. The latter shows how to relabel a recycled VSN and send mail to the superuser.

For more information, see the recycler(1M) and recycler.sh(1M) man pages.

Recycling Process Overview

Using Recycling Directives

Specifying a Log File: The logfile Directive

Preventing Recycling: The no_recycle Directive

Specifying Recycling for an Entire Automated Library: The Library Directive

Planning Recycling Operations

Creating a recycler.cmd File

Example recycler.cmd File

The -hwm 51 Parameter

The -mingain 60 Parameter

The -ignore Parameter

The -mail Parameter

Editing the archiver.cmd File