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we have an SAP process using named PIPES and we were asked to check the shared memory config (IPCS) , i wanted to ask does named PIPES use shared memory at all ? and where are the contents of the file written , can this be viewed .

This is how the file looks like :

prwx------ 1 aaxadm sapsys 0 Apr 21 11:20 MIGRATE_DT_00008.PIPE

we are on 

SUSE Linux Enterprise Server 11 (x86_64)
VERSION = 11
PATCHLEVEL = 2

Thank you Jonu Joy

Marc B
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user3570687
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    Shared memory is something completely different. a named pipe is simply an on-disk inode (think 'file') which has been attached to a process' stdin/stdout. You open that file as usual and use fread/fwrite as you would on any other file, but the kernel will redirect that data to the process at the other end of the pipe as its own stdin/stdout. – Marc B Apr 24 '14 at 21:20
  • are you looking for this ? `cat /proc/sys/fs/pipe-max-size` , but I should warn you: usually any action or utility related with `/proc` is often times considered unreliable. – user2485710 Apr 24 '14 at 21:24
  • possible duplicate http://stackoverflow.com/questions/4739348/is-it-possible-to-change-the-size-of-a-named-pipe-on-linux – user2485710 Apr 24 '14 at 21:24
  • thx Marc, so where does it store the data written , or does it store at all – user3570687 Apr 24 '14 at 21:58

1 Answers1

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While a named pipe exists in the file system, it is actually used only when both the read end and the write end are opened and connected to some program.

A closed pipe cannot contain data, so no data is ever written to disk; the data exists only in memory.

The data is transferred only between these two programs, not shared with an arbitrary number of processes, so this is not shared memory.

CL.
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