Date: Thu, 28 Sep 2000 17:48:46 +0200 From: Brad Knowles <blk@skynet.be> To: John Sconiers <jrs@enteract.com> Cc: Johann Visagie <wjv@cityip.co.za>, chat@FreeBSD.ORG Subject: Re: SGI releases XFS under GPL Message-ID: <v04220806b5f9184cb369@[195.238.1.121]> In-Reply-To: <Pine.NEB.3.96.1000928091033.6947A-100000@shell-1.enteract.com> References: <Pine.NEB.3.96.1000928091033.6947A-100000@shell-1.enteract.com>
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At 9:18 AM -0500 2000/9/28, John Sconiers wrote: > Can you please explain the difference in XFS and softupdates and why soft > updates would be more desireable than a journaling file system. I > understand what XFS is but based on your comments I get the feeling that > I have the wrong impression of what softupdates is and how it > performs. I know there are papers on the subject(s). Any one got a link? The key thing to "softupdates" is that it allows us to completely avoid writing certain disk meta-data updates to disk (so long as they continue to occur in a certain order), whereas log-structured journaling filesystems don't avoid those meta-data updates algtogether, they instead give us a more efficient way to handle them. A more efficient way to handle them is an improvement, but an even better improvement is to simply never do them at all. Unfortunately, I fear that "softupdates" and a log-structured journaling filesystem are mutually incompatible. Damn. You know, Kirk was just here. I should have asked him that question. -- These are my opinions -- not to be taken as official Skynet policy ====================================================================== Brad Knowles, <blk@skynet.be> || Belgacom Skynet SA/NV Systems Architect, Mail/News/FTP/Proxy Admin || Rue Colonel Bourg, 124 Phone/Fax: +32-2-706.13.11/12.49 || B-1140 Brussels http://www.skynet.be || Belgium "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, Historical Review of Pennsylvania. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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