1. Create user
useradd -u 301 -g 200 -d /interface/IR -m -s /bin/csh -c "FTP user - ftpir" ftpir

2. Create directory
mkdir /interface/IR/inb /interface/IR/outb
chmod 775 /interface/IR/inb  /interface/IR/outb
chown ftpir:sapsys /interface/IR/inb  /interface/IR/outb
 
3. Change password
passwd ftpir

4. Add authorization FTP guest user
- Add guest user in /etc/ftpd/ftpaccess
# ident "@(#)ftpaccess  1.2     03/05/14 SMI"
#
# FTP server configuration file, see ftpaccess(4).
#

class           realusers       real            *
class           guestusers      guest           *
class           anonusers       anonymous       *

loginfails      3
passwd-check    trivial         warn
private         no
shutdown        /etc/ftpd/shutdown.msg
# email         user@hostname
# guestuser     username  <<<
# rhostlookup   no

>>
# guestuser     username
guestuser       ftpir

you have a SAP note to calculate the size of the client. it is a
in 46C --> Y*TAB*SIZ*
in 620 --> RSTABLESIZE
it gives total table sizes and you can add totals.