Swestore-dCache

Swestore is a robust, flexible and expandable short and medium term storage system aimed at storing large amounts of data produced by various Swedish research projects. It is based on the dCache.

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 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 and so on.

Getting access

The Call for Proposals is currently closed, but new Proposals will accepted mid June 2016 with new Projects being approved in mid July.

Apply for storage

All regular 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 request a Swestore project.

Acquire an eScience client certificate

Swestore authentication is done using certificates. Follow the instructions on Requesting a certificate to get your client certificate. This step can be performed while waiting for the storage application to be approved and processed. Of course, if you already have a valid eScience certificate you don't need to acquire another one.

Manage your eScience client certificate

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 (not necessarily needed with ARC 3.x, see proxy certificates using Firefox credential store).

For Nordugrid certificates

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

Request membership in the SweGrid VO

Follow the instructions on Requesting membership in the SweGrid VO to get added to the SweGrid Virtual Organisation (VO) and request membership to your allocated storage project.

Support

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

dCache

Access protocols

Currently supported protocols

HTTP/WebDAVProtocol

http://webdav.swestore.se/ (unauthenticated, read-only)

https://webdav.swestore.se/ (authenticated, read-write)

GridFTP - gsiftp://gsiftp.swestore.se/

NFS4.1

(Storage Resource Manager - srm://srm.swegrid.se/)

Download and upload data

Interactive browsing and manipulation of single files

SweStore is accessible in your web browser in two ways, as a simple and reliable directory index interface at https://webdav.swestore.se/ and with a richer interactive file manager at https://webdav.swestore.se/browser/. Note that the interactive file manager has a lot of features and functions not supported in SweStore, only the basic file transfer features are supported.

To browse private data you need to have your certificate installed in your browser (default with Terena certificates, see above). Projects are organized under the /snic directory as https://webdav.swestore.se/snic/YOUR_PROJECT_NAME/.

Upload and delete data interactively or with automation

There are several tools that are capable of using the protocols provided by SweStore national storage. 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.

Use the ARC client. Please see the instructions for Accessing SweStore national storage with the ARC client. Recommended method when logged in on SNIC resources.

Use lftp. Please see the instructions for Accessing SweStore national storage with lftp.

Use cURL. Please see the instructions for Accessing SweStore national storage with cURL.

Use globus-url-copy. Please see the instructions for Accessing SweStore national storage with globus-url-copy.

Tools and scripts

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

• ARC_Tools - Convenience scripts for the arc client (Only a recursive rmdir so far).
• ARC Graphical Clients - Contains the ARC Storage Explorer (SweStore supported development).
• 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.