Date: Sat, 04 Dec 1999 23:05:02 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Mike Smith <msmith@FreeBSD.ORG> Cc: match@elen.utah.edu, current@FreeBSD.ORG, mckusick@mckusick.com Subject: Re: Mounting one FS on more than one system Message-ID: <14994.944345102@critter.freebsd.dk> In-Reply-To: Your message of "Sat, 04 Dec 1999 13:53:26 PST." <199912042153.NAA04820@mass.cdrom.com>
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In message <199912042153.NAA04820@mass.cdrom.com>, Mike Smith writes: >The sticking issue that we discussed was allowing more than one system to >mount a given filesystem; I pressume we're talking R/W mounts here, since a R/O mount obviously would not be a problem. With UFS/FFS there are significant meta-data caching which would need not only high-level locking (for atomic rename(2) calls) but also low-level locking (who allocates a particular free block). In short: a major hazzle. It might be possible to allow one machine R/W and have the others R/O snoop on the same device, but a more agressive write policy would be needed to get closer to real-time behaviour. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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