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How is Anvil different than Purdue Community Clusters?

Anvil is part of the national Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) ecosystem and is not part of Purdue Community Clusters program. There are a lot of similarities between the systems, yet there are also a few differences in hardware, software and overall governance. For Purdue users accustomed to the way Purdue supercomputing clusters operate, the following summarizes key differences between RCAC clusters and Anvil.

Link to section 'Support' of 'How is Anvil different than Purdue Community Clusters?' Support

While Anvil is operated by Purdue RCAC, it is an ACCESS resource, and all support requests have to go through ACCESS channels rather than RCAC ones. Please direct your Anvil questions to the ACCESS Help Desk (https://support.access-ci.org/open-a-ticket) and they will be dispatched to us.

Link to section 'Resource Allocations' of 'How is Anvil different than Purdue Community Clusters?' Resource Allocations

Two key things to remember on Anvil and other ACCESS resources:

In contrast with Community Clusters, you do not buy nodes on Anvil. To access Anvil, PIs must request an allocation through ACCESS.
Users don't get access to a dedicated “owner” queue with X-number of cores. Instead, they get an allocation for Y-number of core-hours. Jobs can be submitted to any of the predefined partitions.

More details on these differences are presented below.

Access to Anvil is free (no need to purchase nodes), and is governed by ACCESS allocation policies. All allocation requests must be submitted via ACCESS Resource Allocation System. These allocations other than the Maximize ACCESS Request can be requested at any time.

Explore ACCESS allocations are intended for purposes that require small resource amounts. Researchers can try out resources or run benchmarks, instructors can provide access for small-scale classroom activities, research software engineers can develop or port codes, and so on. Graduate students can conduct thesis or dissertation work.

Discover ACCESS allocations are intended to fill the needs of many small-scale research activities or other resource needs. The goal of this opportunity is to allow many researchers, Campus Champions, and Gateways to request allocations with a minimum amount of effort so they can complete their work.

Accelerate ACCESS allocations support activities that require more substantial, mid-scale resource amounts to pursue their research objectives. These include activities such as consolidating multi-grant programs, collaborative projects, preparing for Maximize ACCESS requests, and supporting gateways with growing communities.

Maximize ACCESS allocations are for projects with resource needs beyond those provided by an Accelerate ACCESS project, a Maximize ACCESS request is required. ACCESS does not place an upper limit on the size of allocations that can be requested or awarded at this level, but resource providers may have limits on allocation amounts for specific resources.
Unlike the Community Clusters model (where you “own” a certain amount of nodes and can run on them for the lifetime of the cluster), under ACCESS model, you apply for resource allocations on one or more ACCESS systems, and your project is granted certain amounts of Service Units (SUs) on each system. Different ACCESS centers compute SUs differently, but in general SUs are always some measure of CPU-hours or similar resource usage by your jobs. Anvil job accounting page provides more details on how we compute SU consumption on Anvil. Once granted, you can use your allocation’s SUs until they are consumed or expired, after which the allocation must be renewed via established ACCESS process (note: no automatic refills, but there are options to extend the time to use up your SUs and request additional SUs as supplements). You can check your allocation balances on ACCESS website, or use a local mybalance command in Anvil terminal window.

Link to section 'Accounts and Passwords' of 'How is Anvil different than Purdue Community Clusters?' Accounts and Passwords

Your Anvil account is not the same as your Purdue Career Account. Following ACCESS procedures, you will need to create an ACCESS account (it is these ACCESS user names that your PI or project manager adds to their allocation to grant you access to Anvil). Your Anvil user name will be automatically derived from ACCESS account name, and it will look something similar to x-ACCESSname, starting with an x-.
Anvil does not support password authentication, and there is no “Anvil password”. The recommended authentication method for SSH is public key-based authentication (“SSH keys”). Please see the user guide for detailed descriptions and steps to configure and use your SSH keys.

Link to section 'Storage and Filesystems' of 'How is Anvil different than Purdue Community Clusters?' Storage and Filesystems

Anvil scratch purging policies (see the filesystems section) are significantly more stringent than on Purdue RCAC systems. Files not accessed for 30 days are deleted instantly and automatically (on the filesystem's internal policy engine level). Note: there are no warning emails!
Purdue Data Depot is not available on Anvil, but every allocation receives a dedicated project space ($PROJECT) shared among allocation members in a way very similar to Data Depot. See the filesystems section in the user guide for more details. You can transfer files between Anvil and Data Depot or Purdue clusters using any of the mutually supported methods (e.g. SCP, SFTP, rsync, Globus).
Purdue Fortress is available on Anvil, but direct HSI and HTAR are currently not supported. You can transfer files between Anvil and Fortress using any of the mutually supported methods (e.g. SFTP, Globus).
Anvil features Globus Connect Server v5 which enables direct HTTPS access to data on Anvil Globus collections right from your browser (both uploads and downloads).

Link to section 'Partitions and Node Types' of 'How is Anvil different than Purdue Community Clusters?' Partitions and Node Types

Anvil consists of several types of compute nodes (regular, large memory, GPU-equipped, etc), arranged into multiple partitions according to various hardware properties and scheduling policies. You are free to direct your jobs and use your SUs in any partition that suits your jobs’ specific computational needs and matches your allocation type (CPU vs. GPU). Note that different partitions may “burn” your SUs at a different rate - see Anvil job accounting page for detailed description.

Corollary: On Anvil, you need to specify both allocation account and partition for your jobs (-A allocation and -p partition options), otherwise your job will end up in the default shared partition, which may or may not be optimal. See partitions page for details.
There are no standby, partner or owner-type queues on Anvil. All jobs in all partitions are prioritized equally.

Link to section 'Software Stack' of 'How is Anvil different than Purdue Community Clusters?' Software Stack

Two completely separate software stacks and corresponding Lmod module files are provided for CPU- and GPU-based applications. Use module load modtree/cpu and module load modtree/gpu to switch between them. The CPU stack is loaded by default when you login to the system. See example jobs section for specific instructions and submission scripts templates.

Link to section 'Composable Subsystem' of 'How is Anvil different than Purdue Community Clusters?' Composable Subsystem

A composable subsystem alongside of the main HPC cluster is a uniquely empowering feature of Anvil. Composable subsystem is a Kubernetes-based private cloud that enables researchers to define and stand up custom services, such as notebooks, databases, elastic software stacks, and science gateways.

Link to section 'Everything Else' of 'How is Anvil different than Purdue Community Clusters?' Everything Else

The above list provides highlights of major differences an RCAC user would find on Anvil, but it is by no means exhaustive. Please refer to Anvil user guide for detailed descriptions, or reach out to us through ACCESS Help Desk (https://support.access-ci.org/open-a-ticket)