PostgreSQL is used for various things in a dCache system: The SRM, the pin manager, the space manager, the replica manager, the billing, and the pnfs server might make use of one or more databases in single or several separate PostgreSQL servers.
The SRM, the pin manager, the space manager and the replica manager will use the PostgreSQL database as configured at cell start-up in the corresponding batch files. The billing will only write the accounting information into a database if it is configured with the option -useSQL. The pnfs server will use a PostgreSQL server if the pnfs-posgresql version is used. It will use several databases in the PostgreSQL server.
The preferred way to set up a PSQL server should be the installation of the version provided by your OS distribution; however, version 9.5 or later is required. Running the latest version is recommended, as usually they provide better performance and stability.
Install the PSQL server, client and JDBC support with the tools of the operating system.
Initialize the database directory (for PSQL version 9.5 this is
/var/lib/pgsql/9.5/data/), start the database server, and make sure
that it is started at system start-up.
service postgresql-9.5 initdb
|Initializing database: [ OK ]
service postgresql-9.5 start
|Starting postgresql-9.5 service: [ OK ]
chkconfig postgresql-9.5 on
In the installation guide instructions are given for configuring one
PSQL server on the admin node for all the above described purposes
with generous access rights. This is done to make the installation as
easy as possible. The access rights are configured in the file
<database_directory_name>/data/pg_hba.conf. According to the
installation guide the end of the file should look like
...
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD
local all all trust
host all all 127.0.0.1/32 trust
host all all ::1/128 trust
host all all HostIP/32 trust
This gives access to all databases in the PSQL server to all users on the admin host.
The databases can be secured by restricting access with this file. E.g.
...
# TYPE DATABASE USER IP-ADDRESS METHOD
local all postgres ident sameuser
local all dcache password
local all all md5
host all all 127.0.0.1/32 md5
host all all ::1/128 md5
host all all HostIP/32 md5
To make the server aware of this you need to reload the configuration file as the user postgres by:
su -s `which pg_ctl` postgres reload
The password the the user dcache can be set with
[postgres] # psql template1 -c "ALTER USER dcache WITH PASSWORD '<yourPassword>'"
On small systems it should never be a problem to use one single PSQL server for all the functions listed above. In the standard installation, the ReplicaManager is not activated by default. The billing will only write to a file by default.
Whenever the PostgreSQL server is going to be used for another functionality, the impact on performance should be checked carefully. To improve the performance, the functionality should be installed on a separate host. Generally, a PSQL server for a specific funcionality should be on the same host as the dCache cell accessing that PSQL server, and the PSQL server containing the databases for CHIMERA should run on the same host as CHIMERA and the PnfsManager cell of the dCache system accessing it.
It is especially useful to use a separate PostgreSQL server for the billing cell.
Note
The following is work-in-progress.
Create PostgreSQL user with the name you will be using to run PNFS server. Make sure it has CREATEDB privilege.
psql -U postgres template1 -c "CREATE USER johndoe with CREATEDB"
dropuser pnfsserver
createuser --no-adduser --createdb --pwprompt pnfsserver
Table 24.1. Protocol Overview
| Component | Database Host | Database Name | Database User | Database Password |
|---|---|---|---|---|
| SRM | srm.db.hostor if not set: srmDbHost or if not set: localhost |
srm | dcache | --free-- |
| PinManager | pinManagerDatabaseHost or if not set: srmDbHost or if not set: localhost |
pinmanager | pinmanager | --free-- |
| CELL-REPLICAMNGR | replica.db.host or if not set: localhost |
replica | dcache | --free-- |
| PNFS server | localhost | admin, data1, exp0, ... | pnfsserver | --free-- |
| billing | billingDatabaseHost or if not set: localhost |
billing | dcache | --free-- |