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guide:lustre [2020/04/29 15:10]
kevin
guide:lustre [2020/05/06 11:55]
kevin
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 ======The Lustre Parallel File System====== ======The Lustre Parallel File System======
 +
 +
  
 =====Lustre on Lengau===== =====Lustre on Lengau=====
 +
 +Lengau has 16 OSSs arranged in pairs. ​ There are 96 OSTs connected to the 8 pairs. ​ Each OST has an approx. capacity of 43GiB giving a total Lustre storage of 4PiB. Each OSS pair connects to 12 OSTs.  Should one OSS in a pair succumb, the other still retains access to all 12 OSTs.
  
  
 =====Lustre tools===== =====Lustre tools=====
 +
 +The main tool for displaying information on the files and directories of a Lustre file system is ''​lfs''​.
 +
 +====Searching====
 +
 +Use ''​lfs find''​ (instead of the standard GNU ''​find''​ command) to search for Lustre files based on their metadata properties (size, striping, OSTs, etc.).
 +
 +To find all files larger than 1GB:
 +  lfs find <​dirname>​ -size +1G
 +
 +To find all files newer than 60 days:
 +  lfs find <​dirname>​ -ctime -60
 +
  
 =====Best practices===== =====Best practices=====
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   * Between 1GB and 10GB a small stripe should be used (2)   * Between 1GB and 10GB a small stripe should be used (2)
   * 10 to 100GB : use medium striping (2 to 4)   * 10 to 100GB : use medium striping (2 to 4)
-  * Above 100GB: use maximum striping (-c -1)+  * Above 100GB: use maximum striping (-c -1)\\ **Use only this last option with individual files that you know will be above 100GB or use highly parallelized access.** 
 + 
 +To set the striping for a file to 2 
 +  lfs setstripe -c 2 <​filename>​ 
 + 
 +To change the default striping applied to files in a sub-directory to 2 (and only applied to files larger than 1G) 
 +  lfs setstripe -c 2  -s 1G <​dirname>​ 
 + 
 +> Check this ^^^. 
 + 
 +**Note:**  
 + 
 +  *When you change the settings for an existing file, the file will actually only change to the new striping when it is recreated. 
 + 
 +  * The same applies when you change the settings for an existing directory. You will need to rename the directory, create a new directory with the new stripe settings, and then **copy** (not move) the files to the new directory to inherit the new settings. 
 + 
 +See ''​lfs migrate''​ for more. 
  
-> Use only this last option with individual files that you know they will be above 100GB or with a highly parallelized access. 
/var/www/wiki/data/pages/guide/lustre.txt · Last modified: 2020/05/06 11:55 by kevin