The contents of this chapter include all of the following: File system management and optimization, disk quotas (a fair distribution of disk space), file system backups, back up incrementally, logical dump algorithm, file system consistency,. | CSC 322 Operating Systems Concepts Lecture - 22: by Ahmed Mumtaz Mustehsan Special Thanks To: Tanenbaum, Modern Operating Systems 3 e, (c) 2008 Prentice-Hall, Inc. (Chapter-4) Silberschatz, Galvin and Gagne 2002, Operating System Concepts, Ahmed Mumtaz Mustehsan, CIIT, Islamabad 1 Chapter 4 File System File System Management Example File System Lecture22 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 2 Disk space management Manage Free Blocks (Discussed in the last lecture) Manage Disk quota File System Backups File System Consistency File System Performance File System Management and Optimization Lecture-21 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 3 Multiuser OS enforce Disk Quota and ensure that the users do not exceed their quota. Entry in open file table points to quota table One entry for each open file Places limits (soft, hard) on users disk quota System start warning the users exceeding soft limit User may ignore soft limit till number of warnings left after that the user is not . | CSC 322 Operating Systems Concepts Lecture - 22: by Ahmed Mumtaz Mustehsan Special Thanks To: Tanenbaum, Modern Operating Systems 3 e, (c) 2008 Prentice-Hall, Inc. (Chapter-4) Silberschatz, Galvin and Gagne 2002, Operating System Concepts, Ahmed Mumtaz Mustehsan, CIIT, Islamabad 1 Chapter 4 File System File System Management Example File System Lecture22 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 2 Disk space management Manage Free Blocks (Discussed in the last lecture) Manage Disk quota File System Backups File System Consistency File System Performance File System Management and Optimization Lecture-21 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 3 Multiuser OS enforce Disk Quota and ensure that the users do not exceed their quota. Entry in open file table points to quota table One entry for each open file Places limits (soft, hard) on users disk quota System start warning the users exceeding soft limit User may ignore soft limit till number of warnings left after that the user is not allowed to login. (hard limit) Quota imposed on Blocks as well as on files. Illustration on next slide Disk Quotas (A fair distribution of disk space) Lecture22 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 4 Quotas are kept track of on a per-user basis in a quota table. When user logins within soft limit a warning message to delete files before logging out. Disk Quotas Lecture22 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 5 Take Disk Backup on Tape Backups to tape are generally made to handle any of two potential problems: Recover from disaster (. disk crash, nature) Recover from stupidity (. Delete file by mistake) Tapes hold hundreds of gigabytes and are very cheap File System Backups Lecture22 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 6 What to Backup? Don’t want to back up whole file system Can get binaries from manufacturer’s CD’s Temporary files don’t need to be backed up Special files (I/O) don’t need it File System Backups Lecture22 Ahmed Mumtaz Mustehsan, CIIT, Islamabad 7 How to .
