When connecting to PostgreSQL, dCache will always use TCP connections. So, for dCache to use PostgreSQL, support for TCP sockets must be enabled. We realize UNIX domain sockets are easier to work with from a security point of view, however there is no way to use UNIX domain sockets from a Java application.

In contrast to dCache, the PostgreSQL stand-alone client application psql can connect using either a TCP socket or via a UNIX domain socket. Because of this, it is common for PostgreSQL to disable TCP sockets by default, requiring the admin to explicitly configure PostgreSQL so connecting via a TCP socket is supported.

To enable TCP sockets, edit the PostgreSQL configuration file postgresql.conf. This is often found in the /var/lib/pgsql/data, but may be located elsewhere. You should ensure that the line tcpip_socket is set to true; for example:

tcpip_socket = true

Perhaps the simplest configuration is to allow password-less access to the database and the following documentation assumes this is so.

To allow local users to access PostgreSQL without requiring a password, ensure the file pg_hba.conf, usually located in /var/lib/pgsql/data, contains the following lines.

local   all         all                        trust
host    all         all         127.0.0.1/32   trust
host    all         all         ::1/128        trust

Create the Chimera user and database and add the Chimera-specific tables and stored procedures:

[root] # createdb -U postgres chimera
CREATE DATABASE
                
[root] # createuser -U postgres --no-superuser --no-createrole --createdb --pwprompt chimera
Enter password for new role:
Enter it again:
CREATE ROLE

[root] # psql -U chimera chimera -f /opt/d-cache/libexec/chimera/sql/create.sql
psql:/opt/d-cache/libexec/chimera/sql/create.sql:23: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_inodes_pkey" for table "t_inodes"
CREATE TABLE
psql:/opt/d-cache/libexec/chimera/sql/create.sql:35: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_dirs_pkey" for table "t_dirs"
CREATE TABLE
psql:/opt/d-cache/libexec/chimera/sql/create.sql:45: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_inodes_data_pkey" for table "t_inodes_data"
many more like this...
INSERT 0 1
many more like this...
INSERT 0 1
CREATE INDEX
CREATE INDEX
psql:/opt/d-cache/libexec/chimera/sql/create.sql:256: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_storageinfo_pkey" for table "t_storageinfo"
CREATE TABLE
psql:/opt/d-cache/libexec/chimera/sql/create.sql:263: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_access_latency_pkey" for table "t_access_latency"
CREATE TABLE
psql:/opt/d-cache/libexec/chimera/sql/create.sql:270: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_retention_policy_pkey" for table "t_retention_policy"
CREATE TABLE
psql:/opt/d-cache/libexec/chimera/sql/create.sql:295: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_locationinfo_pkey" for table "t_locationinfo"
CREATE TABLE
psql:/opt/d-cache/libexec/chimera/sql/create.sql:311: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_locationinfo_trash_pkey" for table "t_locationinfo_trash"
CREATE TABLE
CREATE INDEX
psql:/opt/d-cache/libexec/chimera/sql/create.sql:332: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicit index "t_acl_pkey" for table "t_acl"
CREATE TABLE
CREATE INDEX

[root] # createlang -U postgres plpgsql chimera
[root] # psql -U chimera chimera -f /opt/d-cache/libexec/chimera/sql/pgsql-procedures.sql
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION
CREATE TRIGGER
CREATE FUNCTION
CREATE TRIGGER
CREATE SEQUENCE
CREATE FUNCTION
CREATE TRIGGER

Database connection settings can be customized in /opt/d-cache/config/chimera-config.xml Specifically you should change the user to “chimera”.

<?xml version="1.0"?>
<config>
        <db fsid="0" url="jdbc:postgresql://localhost/chimera?prepareThreshold=3" drv="org.postgresql
.Driver" user="chimera" pass="" dialect="PgSQL" />
        <nfs>
                <port>2049</port>
                <logLevel>0</logLevel>
                <logFile>/tmp/himera.log</logFile>
        </nfs>
</config>

Although most components in dCache access the Chimera database directly, some rely on a mounted file system for access. The mounted file system is also nice 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 NFS3 server and mount the name space.

Chimera NFS server uses /etc/exports file to manage exports. So it has to exist or be created. The typical exports file looks like this:

/ localhost(rw)
/pnfs
# or
# /pnfs *.my.domain(rw)

Since Chimera is coupled with dCache it uses the same configuration file and won’t start without it. So copy the /opt/d-cache/etc/dCacheSetup.template to /opt/d-cache/config/dCacheSetup.

[root] # /etc/init.d/portmap stop
Stopping portmap: portmap

Start it via script:

[root] # /opt/d-cache/libexec/chimera/chimera-nfs-run.sh start

To automate the launching of that script at startup time, link to it from /etc/init.d/. Then announce it to chkconfig:

[root] # chkconfig --add chimera-nfs-run.sh
[root] # chkconfig chimera-nfs-run.sh on

First we create the root of the Chimera namespace, called ’pnfs’ for legacy reasons.

[root] # /opt/d-cache/libexec/chimera/chimera-cli.sh Mkdir /pnfs

Now we need to add directory tags. For more information on tags see the section called “Directory Tags”.:

[root] # /opt/d-cache/libexec/chimera/chimera-cli.sh Mkdir /pnfs/<your domain>
[root] # /opt/d-cache/libexec/chimera/chimera-cli.sh Mkdir /pnfs/<your domain>/data
[root] # echo "chimera" | /opt/d-cache/libexec/chimera/chimera-cli.sh Writetag /pnfs/<your domain>
/data sGroup
[root] # echo "StoreName sql" | /opt/d-cache/libexec/chimera/chimera-cli.sh Writetag /pnfs/<your do
main>/data OSMTemplate

If you plan to use dCap with mounted file system instead of the URL-syntax (e.g. dccp /pnfs/desy.de/data/file1 /tmp/file1), we 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 31, dCache default port values. They can be altered in /opt/d-cache/config/dCacheSetup

The configuration is done now, so unmount Chimera:

[root] # umount /mnt

Please note that whenever you need to change the configuration, you have to remount the root localhost:/ to a temporary location like /mnt.

The “user's view” of Chimera is automatically mounted by the dCache init script. You have to make sure that the mountpoint is created on the machine (/pnfs). Chimera can be mounted manually with:

[root] # mkdir /pnfs
[root] # mount localhost:/pnfs /pnfs