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**Table of contents**
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[[_TOC_]]
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# Backup procedure
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Personal spaces (home) and group folders are backed on a regular basis on a tape library situated in a different location (at the SEGI, B36). It’s an automatised procedure in which
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any file that has been modified and then did not change for at least 2h will enter a “backing-up queue” and will be backed up as soon as technically possible. In most cases, this
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means that newly
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modified files will be backed up after 2h of inactivity, but the delay could be longer if large files are currently being backed up, if a large number of files have been modified
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recently or if the system is momentarily down for maintenance. In all these cases, it could take several hours before a file is actually backed up.
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The system will keep a maximum of 25 versions of each file for a maximum of 28 days. These will be the 25 last versions, so if a file is backed up 12 times a day, the oldest
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recoverable version will be only 2 days old. Previous versions of a file that have been saved more than 28 days ago will be deleted from the system.
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In other words, it is possible to recover any previous version of a file if
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- that version has been backed up (i.e. stayed inactive for at least 2h after having been modified and saved)
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- that version is less than 28 days old
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- there have not been more than 24 new versions of the file backed up since that version was backed up.
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If a file is deleted from the disk, the last backed-up version will be kept on tape for 28 days.
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Users have to ask the UDI GIGA-MED IT specialist to recover their last backed-up file, or, when possible, one of the previous versions.
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**IMPORTANT**
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As the tape system can only handle a limited amount of data per hour, any action impacting 1 Tb of data or more, for example copying a large dataset or downloading large files,
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must be reported before being performed to the UDI GIGA-MED IT department so that these large changes do not affect the proper functioning of the operations. This rule is applied also in
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if a large number of small files (e.g. several thousands of 1kB files) are created or modified.
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# nobackup folders
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For files that do not require to be backed up, such as temporary files, a specific folder can be created. This folder must be called "nobackup". It must be written exactly like this, without space and in lowercase. Otherwise it will still be backed up.
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# Data archiving procedure
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Once the server will reach 80% of its maximum storage capacity, oldest data will automatically be truncated from the disk in order to save space. Once that happens, there will still be 2 copies of the file on tape but only the beginning of the file and its metadata will stay on disk. Therefore, the file name will still be visible in the tree view but the file itself will be on tape.
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This procedure will affect only files of more than 4Mb and will start with files that haven’t been modified, read or open for at least 270 days. If that’s not enough, “younger” files may be affected too.
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It means that opening data that haven’t been used for a long time will become a slow process, as these data will first need to migrate from tape to drive before to be accessible again. The time required will depend of the ongoing backing up of other files. In optimal conditions, it should take up to 1h to access a 1 TB file.
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