Successful System Cloning using Ignite-UX

10
# mkdir thisisareallylonglonglongnamethatwillnotfitinapaxarchivewhen\
> youareusingustarformatbecausethedirectorynameistoolongandnosuitabl\
> epointwillbefoundtosplititsoitwillfit
# touch thisisareallylonglonglongnamethatwillnotfitinapaxarchivewhen\
> youareusingustarformatbecausethedirectorynameistoolongandnosuitabl\
> epointwillbefoundtosplititsoitwillfit/afilename
# pax -w -f backup.tar -x ustar this*
pax: thisisareallylonglonglongnamethatwillnotfitinapaxarchivewhenyoua
reusingustarformatbecausethedirectorynameistoolongandnosuitablepointw
illbefoundtosplititsoitwillfit/ : Path name element too long – skipped
pax: thisisareallylonglonglongnamethatwillnotfitinapaxarchivewhenyoua
reusingustarformatbecausethedirectorynameistoolongandnosuitablepointw
illbefoundtosplititsoitwillfit/afilename : Path name element too long
- skipped
When splitting the file name, the largest part possible is placed into the name field. In the above
example for the file afilename, the basename will fit into the name field. However the prefix part
that we’re left with is too large for the prefix field so the file cannot be added to the archive. The
directory name that would be placed into the prefix field is more than 155 octets long so it cannot
fit.
If you encounter this issue consider either:
• Changing your directory structure if you want to continue using ustar format and shorten any
directory names that will not fit in ustar format.
• Switching to cpio format archives as they do not have this limitation.
User/Group Name and uid/gid Issues in ustar Format
The pax ustar format stores both a user and group name (limited to 32 octets in length each) and a
uid and gid value.
The standards controlling the behavior of pax require that when restoring an archive in ustar
format the user and group name associated with a file name is used in preference to the uid or
gid information from the ustar format archive if information for the user or group can be retrieved.
This causes an issue if unsupported changes to the uid or gid values for reserved users (those uid
and gid values that are less than 100) are made in the /etc/passwd or /etc/group files on
HP-UX. During a recovery Ignite-UX has access to only a small /etc/passwd file. This file is in a
new configuration state and it is not from the system that is being recovered.
For example, if you were to change the uid of the www user from 30 to 3000 and issue a chown
to change the ownership of the files owned by uid 30 to 3000 you would see problems after a
recovery. Since the www user is a reserved user it is present in the passwd file used by Ignite-UX
during a recovery, this means that the uid the files owned by this user will have been recovered
with a uid of 30 not 3000. Remember that if information about a user can be retrieved, then that
information is used in preference to the uid stored in the archive.