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pages/gmerlin6/introduction.md

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+---
+title: Cluster 'gmerlin6'
+#tags:
+#keywords:
+last_updated: 07 April 2021
+#summary: "GPU Merlin 6 cluster overview"
+sidebar: merlin6_sidebar
+permalink: /merlin5/introduction.html
+redirect_from:
+  - /gmerlin6
+  - /gmerlin6/index.html
+---
+
+## Slurm 'merlin5' cluster
+
+**Merlin5** was the old official PSI Local HPC cluster for development and
+mission-critical applications which was built in 2016-2017. It was an
+extension of the Merlin4 cluster and built from existing hardware due 
+to a lack of central investment on Local HPC Resources. **Merlin5** was 
+then replaced by the **[Merlin6](/merlin6/index.html)** cluster in 2019,
+with an important central investment of ~1,5M CHF. **Merlin5** was mostly 
+based on CPU resources, but also contained a small amount of GPU-based 
+resources which were mostly used by the BIO experiments.
+
+**Merlin5** has been kept as a **Local HPC [Slurm](https://slurm.schedmd.com/overview.html) cluster**,
+called **`merlin5`**. In that way, the old CPU computing nodes are still available as extra computation resources,
+and as an extension of the official production **`merlin6`** [Slurm](https://slurm.schedmd.com/overview.html) cluster.
+
+The old Merlin5 _**login nodes**_, _**GPU nodes**_ and _**storage**_ were fully migrated to the **[Merlin6](/merlin6/index.html)** 
+cluster, which becomes the **main Local HPC Cluster**. Hence, **[Merlin6](/merlin6/index.html)**
+contains the storage which is mounted on the different Merlin HPC [Slurm](https://slurm.schedmd.com/overview.html) Clusters (`merlin5`, `merlin6`, `gmerlin6`).
+
+### Submitting jobs to 'merlin5'
+
+To submit jobs to the **`merlin5`** Slurm cluster, it must be done from the **Merlin6** login nodes by using
+the option `--clusters=merlin5` on any of the Slurm commands (`sbatch`, `salloc`, `srun`, etc. commands).
+
+## The Merlin Architecture
+
+### Multi Non-Federated Cluster Architecture Design: The Merlin cluster
+
+The following image shows the Slurm architecture design for Merlin cluster.
+It contains a multi non-federated cluster setup, with a central Slurm database
+and multiple independent clusters (`merlin5`, `merlin6`, `gmerlin6`):
+
+![Merlin6 Slurm Architecture Design]({{ "/images/merlin-slurm-architecture.png" }})
+