graphing help

[five0.4tluv]

I'm looking through the documentation to find my answers but cannot. this is how I used to do this one graph using rrdtool

snippet

DEF:fsrsanhost1=${RRDDBPATH}/sanhost1-fs_usage.rrd:${RRDFS}reads:AVERAGE DEF:fswsanhost1=${RRDDBPATH}/sanhost1-fs_usage.rrd:${RRDFS}writes:AVERAGE CDEF:fsw1=fswsanhost1,-512,* CDEF:fsr1=fsrsanhost1,512,* \
DEF:fsrsanhost2=${RRDDBPATH}/sanhost2-fs_usage.rrd:${RRDFS}reads:AVERAGE DEF:fswsanhost2=${RRDDBPATH}/sanhost2-fs_usage.rrd:${RRDFS}writes:AVERAGE CDEF:fsw2=fswsanhost2,-512,* CDEF:fsr2=fsrsanhost2,512,* \

..... >

CDEF:totalr=fsr1,fsr2,fsr3,fsr4,fsr5,fsr6,fsr7,fsr8,fsr9,fsr10,fsr11,+,+,+,+,+,+,+,+,+,+ \
CDEF:totalw=fsw1,fsw2,fsw3,fsw4,fsw5,fsw6,fsw7,fsw8,fsw9,fsw10,fsw11,+,+,+,+,+,+,+,+,+,+ \
AREA:totalr#$cdef_dark:"Total Reads" \
AREA:totalw#$cdef_light:"Total Writes\j" \

This is what I've created so far with 10 ports and a custom CDEF to add the RRA's together

DEF:a="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_217.rrd":traffic_in:LAST \
DEF:b="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_218.rrd":traffic_in:LAST \
DEF:c="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_219.rrd":traffic_in:LAST \
DEF:d="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_220.rrd":traffic_in:LAST \
DEF:e="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_221.rrd":traffic_in:LAST \
DEF:f="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_222.rrd":traffic_in:LAST \
DEF:g="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_223.rrd":traffic_in:LAST \
DEF:h="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_224.rrd":traffic_in:LAST \
DEF:i="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_225.rrd":traffic_in:LAST \
DEF:j="/var/www/html/rra/b-dc-cabh-l0-1_traffic_in_226.rrd":traffic_in:LAST \
CDEF:cdefa=a,8,* \
CDEF:cdefb=b,8,* \
CDEF:cdefc=c,8,* \
CDEF:cdefd=d,8,* \
CDEF:cdefe=e,8,* \
CDEF:cdeff=f,8,* \
CDEF:cdefg=g,8,* \
CDEF:cdefh=h,8,* \
CDEF:cdefi=i,8,* \
CDEF:cdefj=j,8,* \
CDEF:cdefba=a,b,c,d,e,f,h,g,i,j,+,+,+,+,+,+,+,+,+,-1,* \
AREA:cdefa:"" \
AREA:cdefb:"" \
AREA:cdefc:"" \
AREA:cdefd:"" \
AREA:cdefe:"" \
AREA:cdeff:"" \
AREA:cdefg:"" \
AREA:cdefh:"" \
AREA:cdefi:"" \
AREA:cdefj:"" \
AREA:cdefba#00CF00FF:"Reads" \
GPRINT:cdefba:LAST:"Last\:%8.2lf %s"

my question becomes: Why do I have to do something with a datasource, why can't I just add it to the graph. I've also used the comment field to accomplish this, but it adds unnecessary /'s to the code.