How about using PREV? You can CDEF:oldvalue=actualvalue, oldtime=TIME. Then you can use CDEF:roc=actualvalue,PREV(oldvalue),-,TIME,PREV(oldtime),-,/
Best regards and HTH, Stephan > assumption: ROC = (y1 - y0) / (x1 - x0) > > my rrd is a gauge of disk space used in bytes. > i assume all I need is to keep the first byte value (y0) > and first timestamp (x0), then cdef it like this: > > CDEF:roc=y1,y0,-,TIME,x0-,/ > > but howto save first values (time = x0, bytes = y0)? > this doesnt work: > > CDEF:y0=y0,UN,used,y0,IF > CDEF:x0=x0,UN,TIME,x0,IF > > Howto save first values? > any other suggestions for ROC calculation? -- Stephan Harren Manager Site Operations AboveNet Deutschland GmbH ------------------------------- Phone +49 69 90554 153 Fax +49 69 90554 111 Cell +49 173 7011126 -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://www.ee.ethz.ch/~slist/rrd-users WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi
