I have answered the question I know the answer to below:
wangxiuwen wrote: > all, > hello!I am a newcomer in ganglia.After i read the paper 'The ganglia > distributed monitoring system',i have some questions.So i come here > for help.Thanks a lot.Maybe someone can give me some clues which > i use to find the right answers. > 1.Every built-in metric has correspondent time thresholds,for example > '900-1200' for cpu_num.But gmond expires monitoring data using > timeouts.For each monitoring metric,it uses two time limits,a soft limit > and a hard limit.What i am wondering is that what 's the relation between > the time threshold,soft limit,hard limit.Are they equal? > 2.what relation exists between node running gmetad and node running > gmond.Can these two daemons must running on different nodes or they > can exist in the same node? gmetad polls a single gmond by connecting to the TCP port of a single node. gmetad may run on the same host as a gmond is running. gmetad can run on any host you choose. > 3.the node running gmetad can get monitoring data from data sources. > Data sources may be either gmond daemons, representing specific clusters, > or other gmetad daemons, representing sets of clusters.does the > communication > between gmetad and gmetad differ from the communication between gmetad > and gmond.Using the same protocol (XML over TCP) or the same interface? The communication only differs in terms of: the TCP port used, and that gmetad can wrap the XML in GRID tags. > 4.Does ganglia has the same event mechinism like the trap in SNMP? No. > 5.Each built-in metric has collect/announce schedule, metric value > thresholds, > metric units and binary to text conversion details. These values can > be modified > at compile time to accommodate different environments.Can these values be > modified when running?For example,I can use some monitored data to change > these value by some policies. No. > 6.If i wanna read the source code of ganglia,where can i start?Can anyone > give me some clues or instructions. Depends what part you are interested in. Interesting files include: libmetrics/linux/metrics.c gmond.c gmetad.c protocol.x > Thanks a lot lot again! Ian
