Managing Data Synchronization

If you have user-created files (non-SSP files that are not contained in the SSP directories) that must be maintained on the spare SSP for failover purposes, you must identify these files in the data propagation list (/var/opt/SUNWssp/.ssp_private/user_file_list) used for data synchronization. The datasyncd daemon uses this list to determine which files to copy from the main SSP to the spare.

By default, the data synchronization process checks for any changes to the user-created files on the main SSP every 60 minutes. You can use the setdatasync command to set the interval at which the data propagation list is to be checked for modifications (see "To Add a File to the Data Propagation List"). The interval starts from the time at which a file is added to the data propagation list. The files in this list are propagated to the spare SSP only when they have changed from the last interval check.

The data synchronization daemon uses the available disk space in the /tmp directory to copy files from the main SSP to the spare. If you have files to be copied that are larger than the /tmp directory, those files cannot be propagated. For example, if the data synchronization backup file (ds_backup.cpio) file gets larger than the available space in /tmp, you must reduce the size of this file before data propagation can occur. For details on reducing the size of the data synchronization backup file, see "To Reduce the Size of the Data Synchronization Backup File".

Use the setdatasync(1M) command to do the following:

• Add a file to the data propagation list and indicate how often this file is to be checked for modifications.

• Remove a file from the data propagation list.

• Erase all entries and temporary files in the data propagation list and remove the data propagation list.

• Push a file to the spare SSP without adding the file to the data propagation list.

• Resynchronize the SSP configuration files between the main and the spare SSP.

The files on the spare SSP are not monitored by the datasyncd daemon, which means that if you remove a user-created file on the spare SSP, the user file will not be automatically restored (copied) from the main to the spare SSP. In addition, do not remove SSP configuration files from the spare SSP.

For additional details, see the setdatasync(1M) man page.

To Add a File to the Data Propagation List

1. As user ssp on the main SSP, type:

   ssp% setdatasync -i interval schedule filename

   where interval indicates the frequency (number of minutes) that the specified filename is to be checked as part of the data synchronization process. The specified file name must contain the absolute path. The files on the data propagation list are copied to the spare SSP only when those files change on the main SSP, and not each time the files are checked.

To Remove a File From the Data Propagation List

1. As user ssp on the main SSP, type:

   ssp% setdatasync cancel filename

   where filename is the file to be removed from the data propagation list. The file name must contain the absolute path.

To Remove the Data Propagation List

The setdatasync clean command is useful for managing disk space in single SSP configurations, where the data propagation list can grow quite large and consume unnecessary disk space. It is possible for the /tmp directory to become full, which can cause the system to hang. You can run the setdatasync clean command as needed, either daily or weekly to prevent the /tmp directory from growing too large. Or, you can automate the cleanup by using the cron(1M) command with a crontab(1M) entry that uses the setdatasync clean command.

Do not use this option when you have a dual SSP configuration because it can desynchronize data between the main and spare SSP.

1. As user ssp on the main SSP, type:

   ssp% setdatasync clean

To Push a File to the Spare SSP

1. As user ssp on the main SSP, type:

   ssp% setdatasync push filename

   where filename is the file to be moved to the spare SSP without adding the file to the data propagation list. The file name must contain the absolute path.

To Resynchronize SSP Configuration Files Between the Main and the Spare SSP

Use this procedure to keep data between the main and spare SSP synchronized. If you want to archive an SSP configuration, use the ssp_backup(1M) command.

1. As user ssp on the main SSP, type:

   ssp% setdatasync backup

   A data synchronization backup file of all SSP configuration data on the main SSP is created and then restored on the spare SSP. Note that the data synchronization backup differs from a backup created by the ssp_backup(1M) command:

   • The data synchronization backup, while similar to a backup created by the ssp_backup command, does not back up the /tftpboot directory.

   • The data synchronization backup does not restore the following files:

     • /var/opt/SUNWssp/.ssp_private/machine_server_fifo

     • /var/opt/SUNWssp/adm/messages

       This file is propagated to the /var/opt/SUNWssp/adm/messages.dsbk file on the spare SSP.

     • /var/opt/SUNWssp/adm/messages.dsbk

     • /var/opt/SUNWssp/.ssp_private/user_file_list

     • /var/opt/SUNWssp/.ssp_private/.ds_queue

   The data synchronization backup can fail if the backup file exceeds the available disk space in the /tmp directory. For details on reducing the size of the data synchronization backup file, see the following procedure.

To Reduce the Size of the Data Synchronization Backup File

1. As superuser on the main SSP, run ssp_backup(1M) to create an archive of your SSP environment.

2. Remove the following files to reduce the size of the data synchronization backup created before you run setdatasync backup:

   • $SSPLOGGER/messages.x

   • $SSPLOGGER/domain/Edd-recovery_files

   • $SSPLOGGER/domain/messages.x

   • $SSPLOGGER/domain/netcon.x

   • $SSPLOGGER/domain/post/files

   where x is the archive number of the file. Because these files are propagated from the new main SSP to the spare after a failover, you must remove these files on both the main and spare SSP to prevent regeneration of these files.

Obtaining Data Synchronization Information

Use the showdatasync(1M) command on the main SSP to obtain basic status information about data synchronization. The examples in this section show the different types of information displayed by the showdatasync command.

The following example shows the status of the datasyncd daemon (file propagation), the files contained in the current data propagation list, and the files queued for data propagation:

ssp% showdatasync 
File Propagation Status:  ACTIVE
Active File:              -
Queued files:             0

The next example shows a data propagation list:

ssp% showdatasync -l  
TIME PROPAGATED         INTERVAL     FILE
Mar 23 16:00:00         60           /tmp/t1
Mar 23 17:00:00         120          /tmp/t2

The example below shows the files queued for data synchronization:

ssp% showdatasync -Q  
FILE
/tmp/t1
/tmp/t2

For additional details, see the showdatasync(1M) man page.