Solaris file system space

UNIX Solaris
1

Hi Experts,

I have query regarding output of df command.

$ df -k
Filesystem           1024-blocks        Used   Available Capacity  Mounted on
rpool/ROOT/solaris-161   191987712     6004395   140577816     5%    /
/devices                       0           0           0     0%    /devices
/dev                           0           0           0     0%    /dev
ctfs                           0           0           0     0%    /system/contract
proc                           0           0           0     0%    /proc
mnttab                         0           0           0     0%    /etc/mnttab
swap                     4184236         496     4183740     1%    /system/volatile
objfs                          0           0           0     0%    /system/object
sharefs                        0           0           0     0%    /etc/dfs/sharetab
/usr/lib/libc/libc_hwcap1.so.1   146582211     6004395   140577816     5%    /lib/libc.so.1
fd                             0           0           0     0%    /dev/fd
swap                     4183784          60     4183724     1%    /tmp
rpool/export           191987712          35   140577816     1%    /export
rpool/export/home      191987712          32   140577816     1%    /export/home
rpool/export/home/123   191987712    13108813   140577816     9%    /export/home/123
rpool/export/repo      191987712    11187204   140577816     8%    /export/repo
rpool/export/repo2010_11   191987712          31   140577816     1%    /export/repo2010_11
rpool                  191987712     5238974   140577816     4%    /rpool
/export/home/123      153686630    13108813   140577816     9%    /home/123

Here file system highlighted in red is having the same size as that of root(/) partition. I have below questions regarding same.

(1) Is this file system created by default during installation?
(2) Why the size of this mount point is same as that of root(/) mount point.

Thanks in Advance for your kind help.

2

It's not really a file system but just a single file overlay mounted on another one. You can just ignore that line.

3

Thanks for your reply.

So what I understood from your reply is that its not actually a file system but a library file fine tuned for specific hardware.

However, I still wonder is why it is mounted if its single file...

Are there any advantages of mounting it?

4

Yes. What alternative(s) would you suggest ?