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LinuxPlanet: ext3 or ReiserFS? Hans Reiser Says Red Hat's Move Is Understandable

Aug 24, 2001, 13:01 (25 Talkback[s])
(Other stories by Dennis E. Powell)
"Red Hat's adoption of ext3 is a first, tentative step toward a journaling filesystem. When the company's plans became known with its release of the second beta of its upcoming release, Michael K. Johnson, chief of the company's kernel hackers, was quick to provide a rationale.

"Why do you want to migrate from ext2 to ext3? Four main reasons: availability, data integrity, speed, and easy transition," he wrote. Availability, he pointed out, involves quick recovery from a system interruption rather than enduring e2fsck taking the long way around. The journaling provided by ext3 makes avoiding data corruption likelier. "Despite writing some data more than once, ext3 is often faster (higher throughput) than ext2 because ext3's journaling optimizes hard drive head motion," he wrote. Perhaps the determining factor, though, was Johnson's fourth reason.

"It is easy to change from ext2 to ext3 and gain the benefits of a robust journaling filesystem, without reformatting," he said. "That's right, no need to do a long, tedious, and error-prone backup, reformat, restore operation in order to experience the advantages of ext3."

Johnson said that Red Hat's choice was not meant to disparage any of the other new filesystems, but instead was the most sensible one for the biggest commercial distribution right now. Indeed, the developers of the various journaling filesystems, too, have gone to considerable lengths to avoid a holy war of the kind that erupts frequently among backers of different projects that perform similar functions.

"I personally think filesystems should be rewritten from scratch every 5 years, but there are lots of people who think quite differently on this," said Hans Reiser, for whom the Reiser filesystem is named, in an email interview yesterday. "Reiser4 is going to have a completely new core engine, and quite a lot of people think that we should just make lots of tweaks to what we have instead. It is extremely expensive, risky, and just plain hard work, for us to do that core engine rewrite, and yet I think it just has to be done. I could give you lots of logical reasons why we are doing it, but those aren't the real reasons why we rewrite when other filesystems don't. People just have different styles, and fortunately both styles work in their way, each with different effects and benefits."

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