Date: Sat, 21 Sep 2002 16:04:03 +0200 (CEST) From: Oliver Fromme <olli@secnetix.de> To: freebsd-questions@FreeBSD.ORG, webmaster@forsetti.com Subject: Re: Using MFS for the first time Message-ID: <200209211404.g8LE43Oa085650@lurza.secnetix.de> In-Reply-To: <3D8C77AC.7080006@forsetti.com>
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Matt Smith <webmaster@forsetti.com> wrote: > Oliver Fromme wrote: > > [...] > > /dev/null /tmp mfs rw,nosuid,nodev,-s=204800,-m=0,-T=minimum 0 0 > > What is the /dev/null component in the MFS line below? I have seen the > swap slice used, but never /dev/null. For that matter, I don't even > really know what that component does -- why do I need to list a device > for a RAM disk? Could someone fill in my knowledge gap? The device column isn't really used for anything when mounting an MFS, _except_ that the mount_mfs command uses the disklabel of that device to initialize some filesystem configuration parameters. It is customary to use the swap partition, but you don't have to. In certain situations you cannot specify a swap partition, because you don't have one (e.g. when you're running swapless, or when your swap is accessed via NFS, or when you're using swap files instead of swap partitions). Under certain circumstances it is also nice to be able to specify the MFS line independent of the actual disk hardware (SCSI, APATI) and where the FreeBSD slice and the swap partition are located. Therefore you can use the -T option to specify a parameter set which is used for the initialization of the MFS. Look at /etc/disktab for the known parameter sets. It doesn't really matter which one you take; the size is irrelevant (it's specified by the -s option). "minimum" is one of them. If you use the -T option, the device (first column in fstab) is meaningless, so you can specify /dev/null or whatever else you like. I think all of that is explained in the mount_mfs(8) and disktab(5) manual pages. Regards Oliver -- Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. "All that we see or seem is just a dream within a dream" (E. A. Poe) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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