mount points

sometimes in Solaris 8 when I go to mount filesystems using either the mount command or by editing the /etc/vfstab, i get a nice little error message saying the the number of allowable mount points has been exceeded. I have read man pages until I am blue in the face and no where can I find what the maximum number of mount points are. Does anyone have any idea on this? Is there a maximum number and where can I find this info?

p.s. the man pages for mount, mount_ufs, vfstab, mnttab, and attributes provided no help. Thanks in advance!!

Please post EXACTLY how you get the error - what you are doing at the time, where your present working directory is, what commands you type in BECAUSE...

it usually that you are:

1. In the directory you are trying to mount on (or someone else is)
2. You run mountall and it gives you an error on the mounted partitions that were mounted before you ran mountall (which means you just ignore the error message).

This sounds like a kernel parm that you need to update. Most systems default, HPUX, to 16 mount points.

Look for a related kernel parm if you are adding additional mount points.

It doesn't seem like Solaris has that problem. I tried and mounted 18 different partitions on a normally built Solaris server - with no problem. And we have systems with over 30 different partitions (DiskSuite and Veritas involved which is why I tested just normal UFS mounts).

..SUN's answer to the question "the limit (if any) of how many mount points are possible?" -

Since a mountpoint is just a directory, I will explain this in terms of
directories. The maximum number of directories allowed on Solaris is limited by
the LINK_MAX parameter.

This parameter is defined as 32767 in the /usr/include/limits.h header file and
it cannot be changed.

In general, you would be hard pressed to exceed the total number of directories
you can have on a filesystem unless you are trying to make more than 32767 in
any one directory.

Since the root filesystem is treated as a directory itself, you are limited to
32767 directories off of root. Each subdirectory is also limited to 32767
subdirectories.

Since each directory can have 32k, and you can nest this as far as you like,
there is no pro-forma limit to the number of files and directories you can have,
other than the number of inodes in your file system. The number of inodes is
an unsigned long and that is 4 billion on a 32-bit system; this means for
example, that you would have to have 128,000 directories (not in any one
subdirectory) with maximum entries of 32k in them (to reach this limit). By
default you get one inode per 2kb of file system space (which is, incidently far
more than you'll ever use on just about any system).

--------------------------------------

And just for completeness, here's the entry from /usr/include/limits.h:

#define LINK_MAX 32767 /* max # of links to a single
file */

So, the 4 billion plus number is 2^32-1 or 4294967295 - the absolute maximum on
a 32-bit system - this is not negotiable as an unsigned long is 32 bits.
Regardless, you'll never exceed (or come close) to this limit as your system
will grind to a halt.