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cluster:93 [2011/01/11 16:36] hmeij |
cluster:93 [2011/01/11 16:43] hmeij |
* you can have multiple public ssh key entries in this file | * you can have multiple public ssh key entries in this file |
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The file **known_hosts** contains server level ssh keys. This is necessary for MPI programs to log into compute nodes withouot a password prompt and submit your jobs. That file has been prepped for you. | The file **known_hosts** contains server level ssh keys. This is necessary for MPI programs to log into compute nodes without a password prompt and submit your jobs. That file has been prepped for you. |
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Previously there were two scratch areas available to your programs: /localscratch which is roughly 50 GB on each node's local hard disk and /sanscratch a shared scratch area available to all nodes. Sanscratch allows you to monitor your jobs progress by looking in /sanscratch/jobpid. It was also much larger (1 TB). | Previously there were two scratch areas available to your programs: /localscratch which is roughly 50 GB on each node's local hard disk and /sanscratch a shared scratch area available to all nodes. Sanscratch allows you to monitor your jobs progress by looking in /sanscratch/jobpid. It was also much larger (1 TB). |
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However, since our fantastic crash of June 2008 ([[cluster:67|The catastrophic crash of June 08]] /snapshot was simply a directory inside /home and thus compete for disk space. | However, since our fantastic crash of June 2008 ([[cluster:67|The catastrophic crash of June 08]] page) /sanscratch was simply a directory inside /home and thus competes for disk space and IO. |
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On greentail, /sanscratch will be a separate logical volume of 5 TB using a different disk set. SO i urge those that have very large files to stage their files in /sanscratch when running their jobs for best performance. The scheduler will always create (and delete!) two directories for you. The JOBPID of your job is used to create /localscratch/jobpid and /sanscratch/jobpid. | On greentail, /sanscratch will be a separate logical volume of 5 TB using a different disk set. So I urge those that have very large files to stage their files in /sanscratch when running their jobs for best performance. The scheduler will always create (and delete!) two directories for you. The JOBPID of your job is used to create /localscratch/jobpid and /sanscratch/jobpid. |
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===== MPI ===== | ===== MPI ===== |