RRDtool update and modify rrd data source at timestamp

Question

I would to modify my rrd file. In particular I would modify one or more datasource data at precise timestamp. I tried to do this with rrdtool update command but without success

Can you help me?

Answer 1

RRD是一个仅插入的数据库...它没有内置的功能可在插入后修改数据...您可以使用rrdtool dump将rrd文件转换为xml格式，修改数据，然后使用rrdtool restore重新创建rrd文件。

Answer 2

RRDTool databases do not support update. This is because they progressively summarise the data into the RRA, and so, as time moves on, no longer have the original raw data but only the summarised data.

In addition - and more importantly - RRD data are subject to Normalisation. This converts the original time/value pair to an adjusted value on the precise time interval boundary. In other words, if your interval is 5min, then a sample submitted for 12:01 will be adjusted proportionately into the 12:00 and 12:05 intervals. So, you cannot store an exact time.

If you are looking to store a series of events with precise times and values, with the original data available and updateable indefinitely, then RRDTool is not an appropriate choice of database. Lok at MySQL, Postgres, and other RDBMS.