dCache does not need the Chimera filesystem to be mounted but
a mounted file system is convenient for administrative access.
This offers the opportunity to use OS-level tools like
ls and mkdir for
Chimera. However, direct I/O-operations like
cp are not possible, since the NFSv3 interface
provides the namespace part only. This section describes how to
start the Chimera NFSv3 server and mount the name space.
If you want to mount Chimera for easier administrative access,
you need to edit the /etc/exports file as
the Chimera NFS server uses it to manage exports. If this
file doesn’t exist it must be created. The typical
exports file looks like this:
/ localhost(rw) /data # or # /data *.my.domain(rw)
As any RPC service Chimera NFS requires rpcbind service to run on the
host. Nevertheless rpcbind has to be configured to
accept requests from Chimera NFS.
On RHEL6 based systems you need to add
RPCBIND_ARGS="-i"
into /etc/sysconfig/rpcbind and restart
rpcbind. Check your OS
manual for details.
[root] #service rpcbind restartStopping rpcbind: [ OK ] Starting rpcbind: [ OK ]
If your OS does not provide rpcbind
Chimera NFS can use an embedded rpcbind.
This requires to disable the portmap
service if it exists.
[root] #/etc/init.d/portmap stopStopping portmap: portmap
and restart the domain in which the NFS server is running.
Example:
[root] #dcache restart namespaceDomain
Now you can mount Chimera by
[root] #mount localhost:/ /mnt
and create the root of the Chimera namespace which you can call
data:
[root] #mkdir -p /mnt/data
If you don’t want to mount chimera you can create the root of the Chimera namespace by
[root] #/usr/bin/chimera-cli Mkdir /data
You can now add directory tags. For more information on tags see the section called “Directory Tags”.
[root] #echo "chimera" | /usr/bin/chimera-cli Writetag /data sGroup[root] #echo "StoreName sql" | /usr/bin/chimera-cli Writetag /data OSMTemplate
If you plan to use dCap with a mounted file system instead of
the URL-syntax (e.g. dccp
/data/file1
/tmp/file1), you need to mount the root of
Chimera locally (remote mounts are not allowed yet). This will
allow us to establish wormhole files so dCap clients can
discover the dCap doors.
[root] #mount localhost:/ /mnt[root] #mkdir /mnt/admin/etc/config/dCache[root] #touch /mnt/admin/etc/config/dCache/dcache.conf[root] #touch /mnt/admin/etc/config/dCache/'.(fset)(dcache.conf)(io)(on)'[root] #echo "<door host>:<port>" > /mnt/admin/etc/config/dCache/dcache.conf
The default values for ports can be found in Chapter 28, dCache Default Port Values (for dCap the default port is
22125) and in the file
/usr/share/dcache/defaults/dcache.properties. They
can be altered in
/etc/dcache/dcache.conf
Create the directory in which the users are going to store their data and change to this directory.
[root] #mkdir -p /mnt/data[root] #cd /mnt/data
Now you can copy a file into your dCache
[root] #dccp /bin/sh test-file735004 bytes (718 kiB) in 0 seconds
and copy the data back using the dccp command.
[root] #dccp test-file /tmp/testfile735004 bytes (718 kiB) in 0 seconds
The file has been transferred succesfully.
Now remove the file from the dCache.
[root] #rm test-file
When the configuration is complete you can unmount Chimera:
[root] #umount /mnt
Note
Please note that whenever you need to change the configuration,
you have to remount the root localhost:/ to a
temporary location like /mnt.