Another way is simply to feed the time in such a way as to guarantee that it's an exact multiple of the step on the step; i.e., if step is 3600, guarantee that the time fed into the RRD is an exact multiple of 3600 (modulo 3600). Obviously, this assumes that you cron it to run on the hour and that a second or two is not a major factro in the data. At least that seems to work for me, Al -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alex van den Bogaerdt Sent: Wednesday, May 11, 2005 8:54 PM To: [email protected] Subject: [rrd-users] Re: Creating RRD/RRA
On Wed, May 11, 2005 at 06:34:05PM -0400, Mike M wrote: > > ... let's say the following is true: > > > > now == around 12:00 METDST today == 1115805601 seconds since epoch > > now == around 13:00 METDST today == 1115809202 seconds since epoch > > now == around 14:00 METDST today == 1115812800 seconds since epoch > > now == around 15:00 METDST today == 1115816401 seconds since epoch > > > > Assume step == 3600 and heartbeat == 3600. What do you think > > happens at time 1115809202 (_around_ 13:00) ? And at 1115816401 ? > > And why? > > > > What do you think if heartbeat is set to 3300 ? Why ? > > I see what you're getting at here, although given the question I think > using the socratic method is a little much. A simple answer would do > just fine, not that I don't appreciate the help. It is the "around" part that is going to cause trouble for you. > > now == around 12:00 METDST today == 1115805601 seconds since epoch > > now == around 13:00 METDST today == 1115809202 seconds since epoch 1115809202 - 1115805601 = 3601 > 3600 => rate = NaN also 1115809202 - 1115805601 = 3601 > 3300 => rate = NaN In general: delta(time) should be <= heartbeat You need to give yourself some space, or you need to get your times fixed (i.e. on the hour _exactly_). I can't tell you what to do, this depends on your requirements. Please do show the list what your next try is, so we can feedback again. cheers Alex -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/rrd-users WebAdmin http://lists.ee.ethz.ch/lsg2.cgi The contents of this e-mail and any attachments are intended solely for the use of the named addressee(s) and may contain confidential and/or privileged information. Any unauthorized use, copying, disclosure, or distribution of the contents of this e-mail is strictly prohibited by the sender and may be unlawful. If you are not the intended recipient, please notify the sender immediately and delete this e-mail. -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/rrd-users WebAdmin http://lists.ee.ethz.ch/lsg2.cgi
