Jaguar Journaling

Elvis is back in the building.

Apple's new update to Jaguar, version 10.2.2, includes a 'journaling file system' which should be interesting at least to system administrators. Developed under the code name Elvis, the project was spearheaded by Dominic Giampaolo, the engineer who created the journaling file system for Be.

The system automatically logs transactions to guarantee file system consistency in the event of a crash, and can retrieve lost data by consulting its log and restoring the file system to its previous state, instead of resorting to use of fsck.

A number of Unix distributions, along with NTFS, have some journaling capabilities, but none go as far as Apple's. And this is a system for use on critical servers rather than active workstations. Count on a 10-15% performance hit if you enable it - something the ordinary Jaguar user will be reluctant to offer.

Still, the system was designed for use with RAID storage - and that hardly fits the ordinary user's picture.

An Apple white paper is available at the following URL.

http://www.apple.com/server/pdfs/L24481A_Journaling_TB.pdf