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HPSS Introduction: Difference between revisions
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== Usage == | == Usage == | ||
For the user, there are currently two ways to access the HPSS environment to store data: ftp and parallel ftp. More information about this is given in the [[User Access]] section. Please | For the user, there are currently two ways to access the HPSS environment to store data: ftp and parallel ftp. More information about this is given in the [[User Access]] section. '''Please remember always''', that your data is stored on tape and might be on disk. Especially, if you have not touched your data for a longer time, it will happen that your data is located on tape only. This may result in some latency at the begin of data transfers when reading data. | ||
=== Class of Service === | === Class of Service === | ||
The only control instrument visible to the outside is the class of service (cos). Each class of service has an id which is used to specify the class of service to be used. The current setup knows three class of service for general usage with different chracteristics. | The only control instrument visible to the outside is the class of service (cos). Each class of service has an id which is used to specify the class of service to be used. The current setup knows three class of service for general usage with different chracteristics. | ||
Revision as of 13:11, 7 October 2008
General
The High Performance Storage System HPSS is developped by several Labs in the US in cooperation with IBM. HPSS is a Hierarchical Storage Management System (HSM) and it is developped to manage petabytes of data stored on disks and in tape libraries.
HPSS at HLRS manages 288 TB of disk storage and more than a petabyte tape storage.
Usage
For the user, there are currently two ways to access the HPSS environment to store data: ftp and parallel ftp. More information about this is given in the User Access section. Please remember always, that your data is stored on tape and might be on disk. Especially, if you have not touched your data for a longer time, it will happen that your data is located on tape only. This may result in some latency at the begin of data transfers when reading data.
Class of Service
The only control instrument visible to the outside is the class of service (cos). Each class of service has an id which is used to specify the class of service to be used. The current setup knows three class of service for general usage with different chracteristics.
cos 112 is for files sized smaller than 2 GB
cos 122 is for files larger than 2 GB but small than 8 GB
cos 132 is for files larger than 8 GB
Depending on the class of service, the internal handling of files is different. Please find more information about this in the chapter Configuration Details below.