Swestore-dCache

Swestore is Research Data Storage Infrastructure operated by the Swedish National Infrastructure for Computing (SNIC).

The resources provided by Swestore are made available through open procedures such that the best Swedish research is supported and new research is facilitated. The purpose of Swestore allocations, granted by Swedish National Allocations Committee (SNAC), is to provide large scale data storage for “live” or “working” research data, also known as active research data.

Due to the VR funding, the free allocations on Swestore have some usage limitations.

• Swestore is NOT supposed to be used for backups and such requests for allocation will be rejected. Please, check with your university (home institution/organisation) IT department about backup services, strategies and policies in place. If such services do not exist or if you can’t access them for different reasons, please contact us at support@swestore.se;
• Swestore is NOT supposed to be used as archiving service, long-term storage or repository for “static” data. Once data is no longer in the process of change, and decision on which data should be retained shared and/or preserved has been taken, data should be moved toward appropriate data services. The higher education institutions are responsible for archiving and long-term preservation of research data produced by researchers employed by them;

Glossary

Active (Research) data

is data that is being worked on as part of research project and therefore subject to change. The files containing data will need to be accessed and amended or updated as new data is gathered or processed.

Static (Research) data

is data that is no longer in the process of change and it can be prepared for preservation and reuse.

Backup

is a copy of the digital data to be stored and used as a replacement in case the main copy is either deleted or corrupted.

Archive

is a service to record, organise, and store (digital) items in optimal conditions, with standardised labelling to ensure their longevity and continued access. The service is based on application of metadata, archiving policies, records management, and digital preservation actions. Archivists make decisions on selection and retention of items which are usually governed by supporting policies.

Swestore is distributed across the SNIC centres C3SE, HPC2N, Lunarc, NSC and Uppmax. Data is stored in two copies with each copy at a different SNIC centre. This enables the system to cope with a multitude of issues ranging from a simple crash of a storage element to losing an entire site while still providing access to the stored data.

One of the major advantages to the distributed nature of Swestore is the excellent aggregated transfer rates possible. This is achieved by bypassing a central node and having transfers going directly to/from the storage elements if the selected transfer protocol allows it. Swestore can achieve aggregated transfer rates in excess of 100 Gigabit per second, but in practice this is limited by connectivity to the end user, each university or a limited number of files (typically max 1 Gbit/s per file/connection).

To protect against silent data corruption the dCache storage system checksums all stored data and periodically verifies the data using this checksum.

The dCache system does NOT yet provide protection against user errors like inadvertent file deletions.

Getting access to Swestore

These steps are required for all PI:s and users of Swestore regardless of how the storage area later is accessed.

NOTE: This documentation section is being rewritten, check back in a few days unless you're in a hurry.

Apply for storage (for the PI)

All normal Swestore projects are managed using the SNIC User and Project Repository portal, SUPR. Please follow the instructions on the Apply for storage on Swestore page to apply for storage.

Apply for project membership (for all users)

All project members have to register in SUPR and be added to the approved project by the PI. This can happen in multiple ways:

• The PI can add you to a project
• You can request membership to a project

When your project membership is approved by the PI the Swestore system will map an account for you and add access to the project storage directory. Please wait for up to 10 minutes for this information to be distributed to Swestore.

Finding the project storage directory name (for all users)

All Swestore projects are assigned a unique directory name, this is used to locate your storage area.

To find the directory name for a storage project, perform these steps:

• Log in to SUPR
• Click on the project ID in the left hand menu.
• The project Directory Name is shown in the Basic Information section.

The project storage area is available in the path /snic/directory_name/ on Swestore.

Set your Swestore password (for users accessing via username/password authentication)

The username/password access methods requires you to set a password on your Swestore account.

Follow the instruction on the page Setting your Swestore password.

Acquire and manage certificate (for users accessing via certificate authentication)

Certificate authentication is needed in some special cases, and more convenient in many automation use cases.

Some communities require certificate authentication and such users might already have a certificate, that certificate is likely good to use with Swestore.

Acquire an eScience client certificate

If you already have a valid grid or eScience certificate you don't need to acquire another one.

Acquire a certificate by following the Requesting a certificate instruction step only on the certificate documentation page. This step can be performed while waiting for the storage application to be approved.

Manage your eScience client certificate

There are multiple suppliers of certificates. Depending on the supplier this step varies a bit.

For Digicert certificates

If intending to access Swestore from a SNIC resource, please make sure you also export the certificate, transfer it to the intended SNIC resource and prepare it for use with grid tools.

For Nordugrid certificates

Please make sure to also install your client certificate in your browser.

Register your eScience client certificate in SUPR

You have to register the certificate in SUPR for Swestore to be aware of it. Make sure your certificate is stored in your browser, log in to SUPR , click Personal Information in the left menu, click Register Client Certificate and follow the instructions. Please wait for up to 10 minutes for this information to be distributed to Swestore.

Using Swestore

Download and upload data

From the command line

There are several command line tools capable of using the protocols provided by Swestore. For interactive usage on SNIC clusters we recommend using the ARC tools which should be installed on all SNIC resources.

As an integration point for building scripts and automated systems we suggest using the curl program and library.

ARC

Please see the instructions for Accessing Swestore with the ARC client. Recommended method when logged in on SNIC resources.

cURL

Please see the instructions for Accessing Swestore with cURL. We suggest using this as integration point for building scripts and automated systems.

globus-url-copy

Please see the instructions for Accessing Swestore with globus-url-copy.

gfal2

(not documented yet)

https://duck.sh/

Command-line client for Windows/macOS (not documented yet)

Using a GUI client

Graphical User Interface (GUI) clients are known to work on some operating systems.

Cyberduck

Please see the instructions for Accessing Swestore using Cyberduck Recommended method on Windows and macOS

From a web browser

Swestore is accessible in your web browser as a simple directory index interface at https://webdav.swestore.se/.

Web browser access supports both username/password and certificate authentication.

Projects are organized under the /snic directory as https://webdav.swestore.se/snic/DIRECTORY_NAME/.

Enabled access protocols

A design criteria for Swestore is to provide the storage over a number of standardized and public protocols. There is no vendor specific client needed for access.

GridFTP

Also called gsiftp. Well supported within Swestore.

Features: Transfer checksums. Direct transfer from/to storage pools for high speed transfers.

Access URL: gsiftp://gsiftp.swestore.se/

HTTP/WebDAV

Contender for being the recommended protocol for Swestore.

Features: Support in web browsers. Supports direct transfer of files from/to storage pools improving performance (varying support in clients).

Authenticated access

This is the normal read-write access.

Access URL: https://webdav.swestore.se/ (non-redirected)

Access URL: https://webdav.swestore.se:1443/ (redirected)

Access URL: https://webdav.swestore.se:2443/ (redirected reads)

Unauthenticated read-only access

For special cases only.

Access URL: http://webdav.swestore.se/ (unauthenticated, read-only, non-redirected)

Access URL: http://webdav.swestore.se:1080/ (unauthenticated, read-only, redirected)

Access URL: http://webdav.swestore.se:2080/ (unauthenticated, read-only, redirected reads)

NFSv4.1

Used by some communities, not recommended for general use

SRM - Storage Resource Manager

Used by some communities, not recommended for general use.

Access URL: srm://srm.swegrid.se/

Xrootd

Used by some communities, not recommended for general use

DCAP

Used by some communities, not recommended for general use

Tools and scripts

There exists a number of tools and utilities developed externally that can be useful. Here are some links:

• ARC Graphical Clients - Contains the ARC Storage Explorer
• Transfer script, swetrans_arc, provided by Adam Peplinski / Philipp Schlatter
• Documentation of the ARC Python API (PDF)

Slides and more

Slides and material from seminar for Lund users on April 18th

Usage monitoring

• On the project page in SUPR: https://supr.snic.se
• On the monitoring server for Swestore: http://status.swestore.se/munin/monitor/monitor/ (only accessible from .se-domains.

Support

If you have any issues using Swestore, please do not hesitate to contact support@swestore.se.