Date: 13 Dec 2000 12:53:54 +0100 From: Dag-Erling Smorgrav <des@ofug.org> To: Gustavo Vieira Goncalves Coelho Rios <gustavo@ifour.com.br> Cc: hackers@FreeBSD.ORG Subject: Re: very big mail spool directory Message-ID: <xzpsnns4jvx.fsf@flood.ping.uio.no> In-Reply-To: Gustavo Vieira Goncalves Coelho Rios's message of "Tue, 12 Dec 2000 20:50:20 %2B0000" References: <3A368F8C.1918684F@ifour.com.br>
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Gustavo Vieira Goncalves Coelho Rios <gustavo@ifour.com.br> writes: > The functions that will hash the id, accepts an id as input and returns > a string for the user dir, like: > > Id String returned > 0 0/0/0/0/0/0/0/0 > [..] That gives you 2^32 leaf directories plus approximately 2^28 intermediate directories, which is a helluva lot of inodes (4581298448 to be exact), and your files will be spread all over your disk(s), throwing performance down the drain. If you only have half a million users, pick a prime number K close to the square root of the expected number of users (724 in your case - closest primes are 719 and 727), create that many bucket directories, and place each user in bucket ID mod K. DES -- Dag-Erling Smorgrav - des@ofug.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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