Install the PostgreSQL server with the tools of the operating system.

Initialize the database directory (for PostgreSQL version 9.2 this is /var/lib/pgsql/9.2/data/) , start the database server, and make sure that it is started at system start-up.

[root] # service postgresql-9.2 initdb
Initializing database:                                     [  OK  ]
[root] # service postgresql-9.2 start
Starting postgresql-9.2 service:                           [  OK  ]
[root] # chkconfig postgresql-9.2 on

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, which (for PostgreSQL version 9.2) is located in /var/lib/pgsql/9.2/data, contains the following lines.

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     trust
# IPv4 local connections:
host    all             all             127.0.0.1/32            trust
# IPv6 local connections:
host    all             all             ::1/128                 trust

[root] # service postgresql-9.2 restart
Stopping postgresql-9.2 service:                           [  OK  ]
Starting postgresql-9.2 service:                           [  OK  ]

Create the Chimera database and user.

[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:
You do not need to enter a password.

The dCache components will access the database server with the user srmdcache.

[root] # createuser -U postgres --no-superuser --no-createrole --createdb --pwprompt srmdcache
Enter password for new role: 
Enter it again:
You do not need to enter a password.

Several management components running on the head node as well as the SRM will use the database dcache for storing their state information:

[root] # createdb -U srmdcache dcache

There might be several of these on several hosts. Each is used by the dCache components running on the respective host.

Create the database used for the billing plots.

[root] # createdb -O srmdcache -U postgres billing

And run the command dcache database update.

[root] # dcache database update
PnfsManager@dCacheDomain: 
INFO  - Successfully acquired change log lock
INFO  - Creating database history table with name: databasechangelog
INFO  - Reading from databasechangelog
many more like this...
      

Now the configuration of Chimera is done.

dCache consists of one or more domains. A domain in dCache is a Java Virtual Machine hosting one or more dCache cells. Each domain must have a name which is unique throughout the dCache instance and a cell must have a unique name within the domain hosting the cell.

A service is an abstraction used in the dCache configuration to describe atomic units to add to a domain. It is typically implemented through one or more cells. dCache keeps lists of the domains and the services that are to be run within these domains in the layout files. The layout file may contain domain- and service- specific configuration values. A pool is a cell providing physical data storage services.

In the setup of dCache, there are three main places for configuration files:

The folder /usr/share/dcache/defaults contains the default settings of the dCache. If one of the default configuration values needs to be changed, copy the default setting of this value from one of the files in /usr/share/dcache/defaults to the file /etc/dcache/dcache.conf, which initially is empty and update the value.

DefaultRetentionPolicy=REPLICA
DefaultAccessLatency=ONLINE

Layouts describe which domains to run on a host and which services to run in each domain. For the customized configuration of your dCache you will have to create a layout file in /etc/dcache/layouts. In this tutorial we will call it the mylayout.conf file.

Domains and services are defined in the layout files. Depending on your site, you may have requirements upon the doors that you want to configure and domains within which you want to organise them.

A domain must be defined if services are to run in that domain. Services will be started in the order in which they are defined.

Every domain is a Java Virtual Machine that can be started and stopped separately. You might want to define several domains for the different services depending on the necessity of restarting the services separately.

The layout files define which domains to start and which services to put in which domain. Configuration can be done per domain and per service.

A name in square brackets, without a forward-slash (/) defines a domain. A name in square brackets with a forward slash defines a service that is to run in a domain. Lines starting with a hash-symbol (#) are comments and will be ignored by dCache.

There may be several layout files in the layout directory, but only one of them is read by dCache when starting up. By default it is the single.conf. If the dCache should be started with another layout file you will have to make this configuration in /etc/dcache/dcache.conf.

dcache.layout=mylayout

broker.scheme=none

[dCacheDomain]
[dCacheDomain/admin]
[dCacheDomain/broadcast]
[dCacheDomain/poolmanager]

[dCacheDomain]
[dCacheDomain/broadcast]
[dCacheDomain/loginbroker]
[dCacheDomain/topo]
[dCacheDomain/info]

[namespaceDomain]
[namespaceDomain/pnfsmanager]
[namespaceDomain/cleaner]
[namespaceDomain/dir]

[poolmanagerDomain]
[poolmanagerDomain/poolmanager]

[adminDoorDomain]
[adminDoorDomain/admin]

[httpdDomain]
[httpdDomain/httpd]
[httpdDomain/billing]
[httpdDomain/srm-loginbroker]

[gPlazmaDomain]
[gPlazmaDomain/gplazma]

dCache will need to write the files it keeps in pools. These pools are defined as services within dCache. Hence, they are added to the layout file of your dCache instance, like all other services.

The best way to create a pool, is to use the dcache script and restart the domain the pool runs in. The pool will be added to your layout file.

[<domainname>/pool]
name=<poolname>
path=/path/to/pool
waitForFiles=${path}/data

The property waitForFiles instructs the pool not to start up until the specified file or directory is available. This prevents problems should the underlying storage be unavailable (e.g., if a RAID device is offline).

[root] # dcache pool create /srv/dcache/p1 pool1 poolDomain
Created a pool in /srv/dcache/p1. The pool was added to poolDomain in
file:/etc/dcache/layouts/mylayout.conf.

(local) admin > cd <poolname>
(<poolname>) admin > set gap 2G
(<poolname>) admin > save

Adding a pool to a configuration does not modify the pool or the data in it and can thus safely be undone or repeated.

Restart dCache to start the newly configured components dcache restart and check the status of dCache with dcache status.

[root] # dcache restart
Stopping dCacheDomain 0 1 done
Starting dCacheDomain done
Starting namespaceDomain done
Starting poolmanagerDomain done
Starting adminDoorDomain done
Starting httpdDomain done
Starting gPlazmaDomain done
Starting poolDomain done
[root] # dcache status
DOMAIN            STATUS  PID   USER
dCacheDomain      running 17466 dcache
namespaceDomain   running 17522 dcache
poolmanagerDomain running 17575 dcache
adminDoorDomain   running 17625 dcache
httpdDomain       running 17682 dcache
gPlazmaDomain     running 17744 dcache
poolDomain        running 17798 dcache

By default the Java heap size and the maximum direct buffer size are defined as

dcache.java.memory.heap=512m
dcache.java.memory.direct=512m

Again, these values can be changed in /etc/dcache/dcache.conf.

For optimization of your dCache you can define the Java heap size in the layout file separately for every domain.

[dCacheDomain]
dcache.java.memory.heap=2048m
dcache.java.memory.direct=0m
...
[utilityDomain]
dcache.java.memory.heap=384m
dcache.java.memory.direct=16m