Administrator's Guide for Rational ClearCase LT, Release 2002.05.00, All Platforms

9.1 Choosing Backup Tools

Rational ClearCase LT does not include any backup tools. All ClearCase LT data is stored in standard files, within standard directory trees; thus, you can use any backup tools available to you that can handle the special needs of VOB backup and recovery. Because file-system conventions and backup tools for UNIX and Windows differ, keep platform-specific considerations in mind when choosing a VOB backup tool.

UNIX Backup Issues

On some systems (HP-UX and Solaris, for example), tar resets file access times, which can disrupt cleartext storage pool scrubbing patterns. For example, the scrubber utility, by default, scrubs cleartext files that have not been accessed in more than 96 hours. A nightly tar operation that backs up cleartext pools and resets cleartext file access times will prevent the pools from ever being scrubbed.

The standard UNIX utility cpio(1) is well suited to backing up ClearCase LT data.

Windows Backup Issues

On Windows, VOB backup programs must be able to handle the file system protection and file locking issues unique to that platform. In particular:

It must preserve the protections of the VOB storage directory so that they can be restored correctly when the backup is recovered.

If possible, it should be able to copy files even when they open for writing.

Common Windows backup utilities do not back up files that are open for writing. Unless you have stopped ClearCase on the VOB server host, several VOB database files remain open for writing even when the VOB is locked. If a backup operation skips these files, the backup will be useless. To avoid this problem, do one of the following:

Purchase and configure backup software that can back up files that are open for writing.

Stop ClearCase before performing the backup. The VOB will be inaccessible while ClearCase is stopped. You may be able to decrease the length of time the VOB is inaccessible by copying the VOB storage directory to another on-disk location, re-starting ClearCase, and then backing up the copy

NOTE: Utilities such as ccopy (a ClearCase LT utility) and scopy (from the Windows NT Resource Kit) do not back up files that are open for writing.