{"id":204,"date":"2015-07-02T19:06:08","date_gmt":"2015-07-02T19:06:08","guid":{"rendered":"http:\/\/srvcnthpc001.uct.ac.za\/?page_id=204"},"modified":"2025-05-14T17:13:03","modified_gmt":"2025-05-14T15:13:03","slug":"scratch-policy","status":"publish","type":"page","link":"https:\/\/ucthpc.uct.ac.za\/index.php\/scratch-policy\/","title":{"rendered":"Scratch"},"content":{"rendered":"
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Scratch Storage Policy<\/span><\/span><\/strong><\/span><\/h1>\n

Description of File System: <\/b><\/span><\/p>\n

\/scratch<\/strong> is mounted on all worker nodes. The file system is intended to provide fast disk I\/O. Users are granted a default quota of 100GB in \/scratch and are requested to apply for additional storage by e-mailing the HPC administrators. Quotas are implemented for file system administration. This is the preferred place to put any intermediate files required while a job is executing. Users are expected to move their data from \/scratch to long term storage as part of their workflow. \/scratch<\/strong>\u00a0<\/b>is purposely built as a computational work space and is not intended for long term storage.<\/strong> This file system is not backed up.<\/strong><\/span><\/p>\n

General Usage: <\/b><\/span><\/p>\n

This file system is designed to provide high throughput to disk. We encourage users who have large datasets to upload them directly to \/scratch,<\/strong>\u00a0not \/home. The output of all computation should also be directed to \/scratch<\/strong>. Data that you wish to keep must be downloaded and removed <\/strong>from \/scratch<\/strong>. Please note that you may only store 10GB of data on \/home.<\/span><\/p>\n

File System Backup:<\/b><\/span><\/p>\n

The \/scratch<\/strong> file system is not<\/b> backed up. Any data which is lost cannot be recovered. Ensure that your data is moved off the file system when jobs complete.\u00a0 Scripts and other data that cannot easily be replicated should not be stored in \/scratch<\/strong>.<\/p>\n

File System Quota Policy: <\/b><\/span><\/p>\n

The \/scratch<\/strong> file system is shared space and is intended for temporary processing<\/strong>, not long term storage. Should the \/scratch file system run out of space all users are affected. It is your responsibility to move processed data off the cluster. There are no backups <\/strong>of \/scratch<\/strong><\/p>\n\n\n\n\n\t\n\n\t\n\t\n\t\n\t\n\t
Quota<\/th>Lifespan (days)<\/th>\n<\/tr>\n<\/thead>\n
50GB (default)<\/td>indefinite<\/td>\n<\/tr>\n
500GB<\/td>indefinite<\/td>\n<\/tr>\n
1TB<\/td>12 months by agreement<\/td>\n<\/tr>\n
5TB<\/td>eResearchdata or by agreement<\/td>\n<\/tr>\n
Over 5TB<\/td>eResearchdata<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n

Quota:\u00a0\u00a0<\/b>Storage allocation is applied to a user on the \/scratch file system. These are not<\/b> directory quotas, they are user quotas applied to the entire file system.<\/p>\n

Long term storage:\u00a0\u00a0<\/strong>Users that\u00a0require reliable long term central storage should contact eresearch@uct.ac.za<\/a>. This storage is separate to the HPC cluster.<\/p>\n\r\n\t\t<\/div>\r\n\t<\/div>\r\n\r\n\t

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File System Quota Check: <\/b><\/span><\/p>\n

Users are encouraged to check their quotas by executing the following command:<\/p>\n

myquota<\/strong><\/pre>\n
This will produce two results, your quota in \/home and \/scratch for example:<\/p>\n
The quota is per volume, not per folder. Quota values are refreshed every few minutes.\r\n\r\nVolume   Quota    Used  %Used\r\n\/home    10GB     5GB   50%\r\n\/scratch 100GB   76GB   76%<\/pre>\n\r\n\t\t<\/div>\r\n\t<\/div>\r\n<\/div><\/div><\/div><\/div><\/div><\/section>\n","protected":false},"excerpt":{"rendered":"Scratch Storage Policy Description of File System: \/scratch is mounted on all worker nodes. The file system is intended to provide fast disk I\/O. Users are granted a default quota of 100GB in \/scratch and are requested to apply for additional storage by e-mailing the HPC administrators. Quotas are implemented for file system administration. 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