System information

14 Sharing and maintaining SLES 10 SP2 Linux under z/VM
The methodology used to name subdirectories of /srv is unspecified as there is currently
no consensus on how this should be done. One method for structuring data under /srv is
by protocol, e.g. ftp, rsync, www, and cvs.
On large systems it can be useful to structure /srv by administrative context, such as
/srv/physics/www, /srv/compsci/cvs, etc. This setup will differ from host to host. Therefore,
no program should rely on a specific subdirectory structure of /srv existing or data
necessarily being stored in /srv. However /srv should always exist on FHS compliant
systems and should be used as the default location for such data.
Distributions must take care not to remove locally placed files in these directories without
administrator permission. This is particularly important as these areas will often contain
both files initially installed by the distributor, and those added by the administrator.”
Other directories
In addition to the directories defined by the Linux Standard Base, Nationwide has included
this directory.
/local
This directory contains local content specific to this server. The subdirectories for local copies
of /etc/, /dev/ and /root/ are located here, with bind mounts to the root directory.
1.3.5 Overview of bind mounts
The /var/, /root/ and /srv/ directories are implemented on the read-only root systems by
means of bind mounts. A background is given on these types of mounts to help explain how
the solution will work and text was taken from the IBM Redbook Linux on IBM eServer
zSeries and S/390: Large Scale Linux Deployment, SG24-6824. This redbook is online at:
http://w3.itso.ibm.com/abstracts/sg246824.html?Open
A bind mount expands the functionality of the device file system mount. Using bind mounts, it
is possible to graft a directory sub-tree from one part of the global file system to another. Bind
mounts differ from device mounts in that the source is the global file system itself - not a block
device.
As an example, consider a directory /guestvol/there containing a file named foo.bar. An
additional directory /mnt/here exists in the global name space. Issue the following command:
# mount --bind /guestvol/there /mnt/here
Now the same file, foo.abc, can be referenced by two path names:
/guestvol/there/foo.abc, the original path name, and /mnt/here/foo.abc, the bind mount
path name.
This is illustrated in Figure 1-9. Both names refer to the same underlying file. The following
bind mounts are added to the root file system to support a read-only root.
mount -n /local
mount -n --bind /local/etc /etc
mount -n --bind /local/root /root
mount -n --bind /local/srv /srv
The Linux kernel maintains coherence and consistency whichever name is used.