System requirements
===================

Hardware
--------

OMERO.server
^^^^^^^^^^^^

The system requirements for OMERO.server vary greatly depending on image
size and number of users. The minimum requirements should be easily exceeded
by any recently bought hardware.

An OMERO.server specification for between 25-50 users might be:

-  Quad-core Intel or AMD CPU
-  8 GB RAM
-  256 GB solid-state drive space for OMERO.server distribution
-  Hard drive space proportional to the image sizes expected (likely
   between 10 and 100 TB)

A specification for a server future-proofed for 3-4 years might be:

-  Intel Xeon Gold 6426 Processor
-  32 GB DDR5-4800
-  2 x 2 TB SSD RAID1 for OS, PostgreSQL DB, scratch, log files, etc.
-  10 GbE connectivity to a separate fileshare for the OMERO binary repository

Storage
"""""""

Hard drive space should be 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:`binary repository </sysadmins/unix/server-binary-repository>` section
for more information.

RAM
"""

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

CPU
"""

CPU is not something that an OMERO system is usually ever limited by. However,
when it is limited, it is almost always limited by `single thread performance 
<https://www.cpubenchmark.net/singleThread.html#server-thread>`__ and not by 
the CPU core count. A 16 system core count should be more than enough. You are
not going to get a huge OMERO performance increase by, for example, throwing
24 cores at the problem; a specification with a focus on higher single thread
performance is going to give you better performance.

Further examples
""""""""""""""""

:doc:`server-setup-examples` provides details on some production set-ups
in use by OMERO admins, along with how many users and the amount of data they
support, which you may find helpful.

OMERO.insight and OMERO.importer
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The recommended client specification is:

-  Intel or AMD CPU
-  8 GB RAM
-  120 GB solid-state drive (SSD)

.. _client_directories:

Client configuration
^^^^^^^^^^^^^^^^^^^^

When performing some operations the clients make use of temporary file
storage and log directories. The table below indicates the default values for
each directory and the environment variables for overriding their locations:

.. list-table::
  :header-rows: 1

  - * Client directory
    * Environment variable
    * Default location (UNIX)
    * Default location (Windows)
  - * OMERO user directory
    * :envvar:`OMERO_USERDIR`
    * :file:`$HOME/omero`
    * :file:`%HOMEPATH%\\omero`
  - * Temporary files
    * :envvar:`OMERO_TMPDIR`
    * :file:`$HOME/omero/tmp`
    * :file:`%HOMEPATH%\\omero\\tmp`
  - * Local sessions
    * :envvar:`OMERO_SESSIONDIR`
    * :file:`$HOME/omero/sessions`
    * :file:`%HOMEPATH%\\omero\\sessions`
  - * Log files
    *
    * :file:`$HOME/omero/log`
    * :file:`%HOMEPATH%\\omero\\log`

Note that setting :envvar:`OMERO_USERDIR` will also change the default location
for the temporary files and the local 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.

.. seealso::
   :ref:`client_performance`
       Troubleshooting section about client performance issues on NFS

Software
--------

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.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
============== =============================== ======== ======== ======== ==========

For full details on which versions of these are supported for OMERO |current_version|
and how we intend to update these going forward, see the
:doc:`version-requirements` section.
