Question 5: Sun Certified System Administrator

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Objective:

Perform System Backups and Restores
SubObjective:

Perform Solaris 10 OS file system restores using the appropriate commands, including restoring a regular file system, the /usr file system, the /(root) file system, and performing interactive and incremental restores for SPARC, x64, and x86 based systems

Single Answer Multiple Choice

You backed up the /export/home file system to a tape device using the ufsdump command. You now need to restore the entire file system to the /var/tmp file system. You use the ufsrestore command. What happens to the inode allocation of the /export/home file system?

A. The inode numbers of the files in the restored exporthome file system are identical to their inode numbers on the tape.
B. The ufsrestore command tries to assign the same inode numbers to the exporthome file system as recorded on the tape.
C. The inode allocation of the exporthome file system changes.
D. The restore of the exporthome file system fails if its inode numbers are the same as the inode numbers already allocated in its cylinder group.

Answer:
C. The inode allocation of the exporthome file system changes.

Tutorial:
When you use the ufsrestore command to restore the exporthome file system, its inode allocation will change. An inode contains information about a file, its owner, permissions, and its size. Inodes are numbered, and each file system contains its own list of inodes. Inodes do not contain information regarding the file name. An inode is 128 bytes in size, and its information is kept in the cylinder information block. A cylinder is a stack of concentric tracks on which the information is saved on a disk. Each file system is divided into cylinder groups with a minimum default size of 16 cylinders in each group. In this scenario, the ufsrestore command repositions the files in the exporthome file system without changing their contents. This leads to a change in the information related to inode allocation. Therefore, you should always perform a level 0 dump or full back of the restored file system after a full restore. This allows you to make a backup of the information regarding the new set of directories reflecting the new file positions and ensures that incremental dumps made later are correct.

The inode numbers of the files in the restored exporthome file system are not identical to their inode numbers on the tape. The ufsrestore command repositions the files in the restored exporthome file system without changing their contents. This leads to change in the information related to inode allocation. Therefore, the inode numbers of the files in the restored exporthome file system also changes and are not identical to the inode numbers on the tape.

The ufsrestore command does not try to assign the same inode numbers to the exporthome file system as recorded on the tape. The ufsrestore command repositions the files in the exporthome file system without changing their contents. This leads to change in the information related to inode allocation.

Reference:
Solaris 10 System Administrator Collection, System Administration Guide: Devices and File Systems, Chapter 23 UFS File System (Reference), http://docs.sun.com/app/docs/doc/817-5093/6mkisoq97?a=view.

Solaris 10 Reference Manual Collection, man pages section 1M: System Administration Commands, System Administration Commands, ufsrestore(1M) incremental file system restore, http://docs.sun.com/app/docs/doc/816-5166/6mbb1kqjk?a=view.

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