Bureaucrats, cc_docs_admin, cc_staff
2,306
edits
Using nearline storage: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
| Line 3: | Line 3: | ||
==Nearline is a filesystem virtualized onto tape== <!--T:1--> | ==Nearline is a filesystem virtualized onto tape== <!--T:1--> | ||
Nearline storage is a hybrid disk/tape filesystem with a layout like [[Project layout|Project]], which however uses its hybrid nature to take advantage of both the the large amount of inexpensive storage available by tape and the rapid access to data that disk offers. You can move your less frequently needed data to tape, where they will no longer count against your project space quota. If you later need these files, you can recall them from tape back to disk with a delay ranging from a few minutes up to an hour or two. | Nearline storage is a hybrid disk/tape filesystem with a layout like [[Project layout|Project]], which however uses its hybrid nature to take advantage of both the the large amount of inexpensive storage available by tape and the rapid access to data that disk offers. You can move your less frequently needed data to tape, where they will no longer count against your project space quota. If you later need these files, you can recall them from tape back to disk with a delay ranging from a few minutes up to an hour or two. | ||
<!--T:2--> | <!--T:2--> | ||
This is useful because the capacity of our tape libraries is both large and expandable. When a file has been moved to tape | This is useful because the capacity of our tape libraries is both large and expandable. When a file has been moved to tape or ''virtualized'', it will still appear in the directory listing. If the virtual file is read, the reading process will block for some time, probably a few minutes, while the file's contents are recalled from tape to disk. | ||
<!--T:24--> | <!--T:24--> | ||
You can | You can determine whether or not a given file has been moved to tape or is still on disk using the <code>lfs hsm_state</code> command: | ||
<!--T:25--> | <!--T:25--> | ||
| Line 25: | Line 24: | ||
<!--T:27--> | <!--T:27--> | ||
" | The "hsm" used in this command stands for "hierarchical storage manager". If you wish to explicitly force a file to be recalled from tape, you can use the <code>lfs hsm_restore <FILE></code> command. | ||
The difference with reading the file is that the restore would be implicitly done. | The difference with reading the file is that the restore would be implicitly done. | ||