Date: Tue, 21 Jul 1998 15:35:22 -0500 (CDT) From: Joel Ray Holveck <joelh@gnu.org> To: joe@via.net Cc: questions@FreeBSD.ORG Subject: Re: mount -o sync question Message-ID: <199807212035.PAA01671@detlev.UUCP> In-Reply-To: message from Joe McGuckin on Tue, 21 Jul 1998 00:56:18 -0700 References:
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> The default mode of ufs filesystems is 'sync'? > Yet if I examine the state of the mounted filesystem using the mount > command, no indication is given of a filesystems (sync vs. async) state. > Yet if I deliberately set the mode to 'sync', mount will now indicate that > the filesystems are mounted synchronously. > www# mount > /dev/sd0a on / (local) > /dev/sd0s1f on /usr (local, synchronous) > /dev/sd0s1e on /var (local) > procfs on /proc (local) > /dev/sd1s1e on /home1 (local, synchronous) > Why is this? This would seem to indicate the 'sync' is not really > the default state of a filesystem (or at least that the sync 'bit' > in whatever data structure that represents a mount point isn't > normally set). Normally, FreeBSD writes file data to the disk asynchronously, but metadata (stuff like directory entries) synchronously. 'mount -o async' means to write everything async, and 'mount -o sync' means write everything sync. We really need to either update the man page to show this or write an FAQ entry. Happy hacking, joelh -- Joel Ray Holveck - joelh@gnu.org - http://www.wp.com/piquan Fourth law of programming: Anything that can go wrong wi sendmail: segmentation violation - core dumped To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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