Date: Wed, 22 Feb 2006 10:03:44 GMT From: Miguel Lopes Santos Ramos <miguel@anjos.strangled.net> To: freebsd-stable@freebsd.org, rossiya@gmail.com Subject: Re: Remote tunefs -n enable Message-ID: <200602221003.k1MA3ixi001559@compaq.anjos.strangled.net> In-Reply-To: <28a99ba50602212307g48db9a53m322fba44eb315a17@mail.gmail.com>
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> From owner-freebsd-stable@freebsd.org Wed Feb 22 09:33:12 2006 > Date: Tue, 21 Feb 2006 23:07:36 -0800 > From: MC <rossiya@gmail.com> > To: freebsd-stable@freebsd.org > Subject: Remote tunefs -n enable > > Hello again > > I have another issue on the same box. The bloke who installed FreeBSD 6.0onto > the machine is a linux man. He didn't know about softupdates nor apparently > does > he know yet about option 4 [read only singule user mode] on the bootloader. > > Consequently he hasn't set softupdates on the main '/' partition It wasn't his fault. It is the default install option. You see, root is mainly a read file system. Typical writes are a kernel install (not too important to optimize) and updating configuration files (it shouldn't be so often). Therefore there isn't much need to optimize / with softupdates. Furthermore, if one can avoid any risky operation on /, all the better. I think that's why the option for / is using synchronous writes without softupdates (not that softupdates are risky, but really they're not much use). > On Freebsd 4.x from ssh2 I used to: > > mount -fr /dev/ad0s1a / > tunefs -n enable /dev/ad0s1a > mount /dev/ad0s1a / > > but attempting this on FreeBSD 6.x immediately locks up the machines when in > multiuser mode. Locks up? That's weird... Perhaps ssh doesn't like it?... Do you have separate /tmp and /var partitions? > On a workstaion I then tried to sneak tunefs into the first lines of > /etc/rc. Unfortunately it seems that > '/' is read/write mounted before /etc/rc runs, so the tunefs just makes an > error and the box boots up > again without softupdates. My question then is how to go about getting the > tunefs line in a startup > script, before the disk is mounted read/write and with realtime access only > in multiuser mode by telnet/ssh2. > > Or perhaps there is another means, this being BSD? I think the filesystem must be unmounted to enable softupdates. Draw your own conclusions. But don't do that unless you have good reason for it. / is a mainly read filesystem. It won't be under heavy write load. On FreeBSD disks are commonly partitioned according to the usage profile, not so common on Linux default installations. That's why separate / /tmp /var /usr and possibly /usr/local, etc. Miguel
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