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The (chprj - change project) command makes it easier to manage the different WORK areas for different projects, see here for details.
$FAST: permanent, project specific, local (LEONARDO ONLY)
$FAST is a scratch area for collaborative work within a given project. File retention is related to the life of the project. Files in $FAST will be conserved up to 6 months after the project end, and then they will be cancelled. Please note that there is no back-up in this area.
This area is conceived for hosting working data files whenever the I/O operations constitute the bottleneck for your applications. It behaves well both when I/O is performed accessing large blocks of data, and for frequent and small I/O operations. Due to the limited size of the area, main space for maintaining the data resulting from batch processing is the corresponding $WORK area.
There is one $FAST area for each active project on the machine. The fixed quota is 1 TB per project, and due to the total dimension of the storage, extensions cannot be considered. The owner of the main directory is the PI (Principal Investigator) of the project. All collaborators are allowed to read/write in there. Collaborators are advised to create a personal directory in $WORK for storing their personal files. By default, the personal directory will be protected (only the owner can read/write), but protection can be easily modified, for example by allowing write permission to project collaborators through chmod command. This second approach does not affect global files security.
The (chprj - change project) command makes it easier to manage the different FAST areas for different projects, see here for details.
$CINECA_SCRATCH: temporary , user specific, local
This is is a local temporary storage , like $WORK, conceived for temporary files from batch applications. There are important differences with respect to $WORK area. It is user specific (not project specific), and it can be used for sharing data with people outside your project. By default, file access is open closed to everyone, in case you need more less restrictive protections, you can set them with chmod command.
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| $CINECA_SCRATCH | $WORK | $DRES |
|---|---|---|
Created when username has granted access. | Created when a project is opened. | Created on request. |
A clean-up procedure is active. | Data are preserved up to few months after the end of the project. | Data are preserved up few months after the expiring date No backup. |
No quota. | Default quota of 1 TB. Motivated requests for quota increase will be taken into account. | Quota based on the needs. |
| By default files are public (read only). The user can change the permission (chmod) and make files private. It is not possible to restrict access to the group (all usernames share the same mail unix group). | By default files are private. The user can change the permission (chmod) and make files visible (R o R/W) to project collaborators. | Same as $WORK area. |
Note: the $FAST area is not reported in the Summary since it is defined on Leonardo cluster only.
What to use when...
| Data are critical, not so large, I want to be sure to preserve them. | $HOME is the right place. Pay attention to the 50 GB quota limit for each user on this space. |
| Large data to be shared with collaborators of my project. | $WORK is the right place. Here each collaborator can have his own directory. He can open it for reading or even writing and be sure, at the same time, that data are not public. People not included in the project will not be able to access the data. Moreover, data are preserved up to a few months after the project’s end. |
| Data to be shared with other users, not necessarily participating in common projects | $CINECA_SCRATCH is the right place. |
| Data to be maintained even beyond the end of the project. I'll use the data on different CINECA hosts | $DRES is a better solution. |
| Data to be shared among different platforms | $DRES allows this. |
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More details are in the help page of the command:
chprj -h
chprj --help
On LEONARDO only: The command applies to the $FAST variable as well.
Endianness
Endianness is the attribute of a system that indicates whether integers are represented from left to right or right to left. At present, all CLusters clusters in Cineca are "little-endian".
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