*******************
System requirements
*******************

Prerequisites overview
======================

Each component of the OMERO platform has a separate set of
prerequisites. Where possible, we provide tips on getting started with
each of these technologies, but we can only provide free support within
limits.

============== =============================== ======== ======== ======== ==========
Package        OMERO.server                    Java     Python   Ice      PostgreSQL
============== =============================== ======== ======== ======== ==========
OMERO.importer Required                        Required
OMERO.insight  Required                        Required
OMERO.editor   Required for some functionality Required
OMERO.server                                   Required Required Required Required
OMERO.web      Required                                 Required Required
OMERO.py       Required for some functionality          Required Required
OMERO.cpp      Required for some functionality                   Required
============== =============================== ======== ======== ======== ==========


OMERO.server
============

The system requirements for OMERO.server vary greatly depending on image
size and number of users. At a minimum we suggest:

-  Ubuntu 10.04 or later / CentOS 6 / Debian 6 (squeeze) or other Linux
   distribution; Mac OS X 10.8 or later; Windows Vista or later
-  Single core 1.33GHz Intel or AMD CPU
-  2GB RAM
-  500MB of hard drive space for OMERO.server distribution
-  Java 1.6 or later
-  Python 2 (2.6.5 or later)
-  Hard drive space proportional to the image sizes expected.
   The drive space should permit **proper locking**, which is
   often not the case with remotely mounted shares. See the
   :doc:`Unix </sysadmins/unix/server-binary-repository>`
   and :doc:`Windows </sysadmins/windows/server-binary-repository>`
   binary repository sections for more information.

The recommended OMERO.server specification we suggest for between 25-50
users is:

-  Ubuntu 12.04 or later / CentOS 6 / Debian 7 (wheezy) or other Linux
   distribution; Mac OS X 10.8 or later; Windows Server 2008
-  Quad core 1.33GHz Intel or AMD CPU
-  8GB RAM
-  500MB hard drive space for OMERO.server distribution
-  Java 1.6 or later
-  Python 2 (2.6.5 or later)
-  Hard drive space proportional to the image sizes expected (Likely
   between 10 and 100TB)

RAM is not going to scale linearly, particularly with the way the JVM
works. You are probably going to hit a hard ceiling between 4 and 6GB for
JVM size (there is really not much point in having it larger anyway).
With a large database and aggressive PostgreSQL caching your RAM usage
could be larger. Still, even for a large deployment, it is not cost
effective to use more than a few GBs of RAM for this purpose.
:doc:`server-performance` provides information about fine-tuning the
server processes' memory usage.

Summary: Depending on hardware layout 16, 24 or 32GB of RAM would be
ideal for your OMERO server. If you have a separate database server more
than 16GB of RAM may not be of much benefit to you at all.

CPU is really not something that an OMERO system is almost ever limited
by. However, when it is limited it is almost always limited by GHz and
not by the CPU count. So you are not going to get a huge OMERO experience
performance increase by, for example, throwing 24 cores at the problem.

Summary: Depending on hardware layout 2 x 4, 2 x 6 system core count
should be more than enough.


OMERO.insight, OMERO.editor and OMERO.importer
==============================================

The recommended client specification is:

-  Ubuntu 12.04 or later / CentOS 6 / Debian 7 (wheezy) or other Linux
   distribution; Mac OS X 10.8 or later; Windows Vista or later
-  Single core 1.33GHz Intel or AMD CPU
-  2GB RAM
-  100MB hard drive space for OMERO.clients distribution
-  Java 1.6 or later

Large imports may require 4GB RAM.


Client configuration
====================

When performing some operations the clients make use of temporary file
storage and log directories. By default these files are stored below
the user's HOME directory in :file:`$HOME/omero/tmp`,
:file:`$HOME/omero/log`, and :file:`$HOME/omero/sessions`
(resp. :file:`$HOME\\omero\\tmp`, :file:`$HOME\\omero\\log`, and
:file:`$HOME\\omero\\sessions`). If your home
directory is stored on a network, possibly NFS mounted (or similar),
then these temporary files are being written and read over the
network. This can slow access down.  The :envvar:`OMERO_TEMPDIR`
environment variable may used to set the directory used for temporary
files, for example on fast local storage.