Date: Wed, 4 Oct 2000 21:57:50 -0400 (EDT) From: Robert Watson <rwatson@freebsd.org> To: "Karsten W. Rohrbach" <karsten@rohrbach.de> Cc: Alex Povolotsky <tarkhil@over.ru>, freebsd-fs@freebsd.org Subject: Re: Specialised storage system? Message-ID: <Pine.NEB.3.96L.1001004215053.13419D-100000@fledge.watson.org> In-Reply-To: <20001005001426.D88159@rohrbach.de>
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On Thu, 5 Oct 2000, Karsten W. Rohrbach wrote: > if your 'application' has some nice strategy for mapping files into a > flat namespace (say: numbered files, 1-d) this might be a nice idea. > implementing some storage on that for rdbms purpose would be a good > point to start. for mail, i think, you need the abstraction layer > in-between to have hierarchical constructs in directory and metadata and > of course permissions. The reason I suggested Cyrus and IFS is that Cyrus already assumes a sealed-box solution, and stores one message per file, keeping meta-data in an independent per-folder hashed database. This model allows a far closer match between message box and file system storage and manipulation semantics: messages are hardly ever modified, but frequently added and removed. Taking out the namespace concerns dramatically reduces the cost of even synchronous deletes, as there are no dependencies other than free lists (which fsck can pick up). There would be increased dependence on a comprehensive database to store meta-data in, perhaps a folder-name-to-inode-number hash could be used for efficiency. Just suggestions. Robert N M Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: AF B5 5F FF A6 4A 79 37 ED 5F 55 E9 58 04 6A B1 TIS Labs at Network Associates, Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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