Date: Sun, 1 Jan 2006 14:56:15 -0400 (AST) From: "Marc G. Fournier" <scrappy@hub.org> To: Francisco Reyes <lists@stringsutils.com> Cc: freebsd-questions@freebsd.org Subject: Re: "Load Balancing": How Busy are the servers? Message-ID: <20060101145325.X1088@ganymede.hub.org> In-Reply-To: <cone.1136049494.118589.27817.1000@zoraida.natserv.net> References: <20051227211433.J1087@ganymede.hub.org> <cone.1136049494.118589.27817.1000@zoraida.natserv.net>
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For all the technology, I was kinda hoping for some 'scientific formula' :) Now, I really hate to ask, but how do you use vmstat to get a feel for how busy the disk subsystem is? What are you looking for? On Sat, 31 Dec 2005, Francisco Reyes wrote: > Marc G. Fournier writes: > >> 1. What variables on a server should be monitored to determine how busy a >> server is? > > I am a fairly new sysadmin.. who inheritted nearly 20 machines, so take my > comments with a gain of salt. Before that the most I ever had was 7, mostly > DB, FreeBSD machines :-) .. and.. Hi Marc. :) > > I think it comes down to primarily 3 factors > * RAM > * CPU > * DISK > > If you are hitting Swap, you are either running too many programs/services or > too many users. > > Same for CPU > > Disk are different in that the same number of disks can perform different > based on what raid controller and what type of RAID. > > I use top and load average to determine if a machine is up to capacity in > memory/cpu. > > I use vmstat to determine if the disk subsystem is falling behind. > > BIG NOTE: The one thing that I have yet to really pay much attention is the > network performance. Fortunately we just hired someone who has significantly > more experience on that area. :-) > > >> 2. Are there any tools that I can run to give me a point in time "summary" >> of how busy a server is based on these several factors? > > I think there are lots of tools. Some vary from SNMP capture/graphing, to > custom made tools done in-house. I think it's a combination of how difficult > it is to setup vs what you need to monitor. > At work we are just starting to roll out an SNMP tool. The new hire is > leading the effort so I am not very familiar with the setups.. the one thing > I see so far is that ultimately, there usually are things that one needs to > monitor that is unique to your organization and you need to either integrate > a program into the tool or do your own independant monitoring of that > particular resource. > > I think the ISP list may be a good resource since the needs of the average > user are different from ISPs/companies with numerous machines. >> Basically, I'd like to keep track of multiple servers and be able to say >> "this server is running >75% of capacity, time to upgrade or move things >> off of it" ... if its possible ... ? > > In my opinion, for the most part, the answer is yes. The problem is usually > how long it's going to take you to setup the environment to monitor the > servers. > > The program we went with was chosen because the new hire was familiar with > it, but a search on the archives for "monitoring tools" will give you a long > list of programs and opinions of which are easier. > > If I had the time, I think I would likely write my own tool. This way I will > be able to measure exactly what I want. Right now I thik we will cover most > basics with the tool we are going with, but will need to still do our own > custom apps to monitor a number of resources and metrics. > > > ---- Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: scrappy@hub.org Yahoo!: yscrappy ICQ: 7615664
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