NAME

       nocache - don't use Linux page cache on given command

SYNOPSIS

       nocache [-n <n>] command [argument...]

OPTIONS

       -n <n> "Set number of fadvise calls"
              Execute  the  `posix_fadvise`  system  call  <n> times in a row.  Depending on your
              machine, this might give better results (use it if in your tests `nocache` fails to
              eradicate pages from cache properly).

DESCRIPTION

       The  `nocache`  tool  tries  to  minimize  the effect an application has on the Linux file
       system cache. This is done by intercepting the `open` and `close` system calls and calling
       `posix_fadvise`  with  the  `POSIX_FADV_DONTNEED` parameter. Because the library remembers
       which pages (ie., 4K-blocks of the file) were already in file system cache when  the  file
       was  opened,  these  will  not be marked as "don't need", because other applications might
       need that, although they are not actively used (think: hot standby).

       Use case: backup processes that should not interfere with the present state of the cache.