freebsd stable - Nov 2006 - adding an extra hard disk and adding space to /usr

Hello all,
    I have a machine that just had a new HD added to it as ad1 and I want to
ADD this new disk onto the already existing /usr partition.  What's the best
and safest way to do it?

                                        Matt

Your only option here as far as I know is to partition the drive to be the new
/usr
partition. To acheive this you would preferrably put the system into single user
mode,
create a partition on the new drive and mount it under /mnt for example.
Then copy all the data between. I prefer to use dump and pipe it into restore
myself
as this preserves all the filesystem flags that would get lost if you would
just do a cp or tar.
Then just update your fstab pointing /usr to the new drive and reboot the
machine.

Baldur

On Fri, Nov 03, 2006 at 05:17:33PM -0500, Matt Smith
wrote:
> Hello all,
>     I have a machine that just had a new HD added to it as ad1 and I want
to
> ADD this new disk onto the already existing /usr partition.  What's the
best
> and safest way to do it?
> 
>                                         Matt
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On Fri, 03 Nov 2006 17:17:33 -0500
Matt Smith <ratman6@charter.net> wrote:
> Hello all,
>     I have a machine that just had a new HD added to it as ad1 and I
> want to ADD this new disk onto the already existing /usr partition.
> What's the best and safest way to do it?
In my experience, there are only a handful of directories in /usr that
uses lots of disk space.
And they are related to two things:
- building the system (/usr/src and /usr/obj)
- building ports (/usr/ports, more specifically /usr/ports/distfiles)

Of course, YMMV.

Anyway, it is quite easy to install the new disk under a new
mountpoint, say .. /extra1
Then you can copy the data from the directories in question with your
favorite combination of cp, tar or find / cpio.
Example:
/usr/ports/distfiles --> /etxtra1/distfiles
/usr/src --> /extra1/usr/src
/usr/obj --> /extra1/usr/obj   (it is perhaps easier to just blow away
						  obj and recreate it -
						  your choice)
and so on.

Finally, you symlink the new directories to their old place using 'ln
-s'.
Note: I prefer to rename the old directory first instead of removing
it, in case something doesn't work.

After testing that the new setup works, you can safely remove the old
renamed directories.

Please also note that this is just one way of doing things - there are
others.

-- 
Torfinn

> Hello all,
Hello Matt,
>     I have a machine that just had a new HD added to it as ad1 
> and I want to
> ADD this new disk onto the already existing /usr partition.  
> What's the best
> and safest way to do it?
Well, I know of two options. One which sounds really cool, is kind
of broken, and is guarteed to cause your kernel crash. So I will 
ignore the mount_union option.

I am no expert on freebsd, but in my opinion tar is a good choice.
Contrary to what others beleive, tar CAN preserve permissions, and 
file ownership. I know that in FreeBSD 4.x  (been there several
times) it can preserve filesystem permissions, and ownership of
files. 

In my opinion, the safest way is to copy /usr to /mnt is via the
following. 
1: Comment out your existing SWAP partition (ad0s1b) in /etc/fstab.
2: reboot
3: remove your existing swap partition.
4: create a new filsystem on each disk that has the same size as
   your ram (1/2 of swap) on each disk. Both (by tradition) will be
   /dev/???s?b. Spanning swap to multiple disks can improve swap
   performance.
5: create a new UFS2 filesystem that contains the rest of the new
   hard drive.
6: mount the new slice as /mnt
7: use the following tar commands as root:
   (FreeBSD 4.x)  : cd /usr; tar clpf - . | (cd /mnt; tar xvf -)
   (FreeBSD 5.x+) : cd /usr; gtar clpf - . | (cd /mnt; gtar xvf -)
8: edit /etc/fstab with your favorite text editor (vi) and duplicate
   the other /usr slice entries. Then comment out the original. And
   update the entry to refer to the correct slice. Next duplicate
   the entry for the other swap partition with the data for the 
   other disk label). SWAP partitions are almost always end in 'b'
9: Due to the fact that killing off all of the applications that
   reside on /usr, its easiest to reboot. But specifically NOT a
   requirement. 


-- Aaron

on 10/11/2006 14:32 Oliver Fromme said the following:
> Aaron Burke wrote:
>  > SNIP
>  > > >    (FreeBSD 4.x)  : cd /usr; tar clpf - . | (cd /mnt; tar
xvf -)
>  > > >    (FreeBSD 5.x+) : cd /usr; gtar clpf - . | (cd /mnt; gtar
xvf -)
>  > > iirc tar(1) has changed in 5.3.  why do you use gtar please? is
new tar
>  > > missing something?
>  > Well, technically no, but it requires more typing.
> 
> That's why I prefer to use cpio:
> 
> cd /usr; find -dx . | cpio -dump /mnt
> 
> which works on _any_ version of FreeBSD out of the box.
$ pax rw /usr /mnt
is even less typing and works on any system with POSIX-compliant
utilities :-)
Not to mention all other goodies that pax provides (I especially like -s
option).

-- 
Andriy Gapon