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>From: Chris Burghart <address@hidden> >Organization: National Center for Atmospheric Research >Keywords: 200305081646.h48Gk37U015345 LDM-6 IDD install tuning Hi Chris, >Joe VanAndel forwarded your message regarding our LDM >on syrah.atd.ucar.edu (a.k.a. ldm.atd.ucar.edu). This machine is showing up in our LDM log files as syrah-78.atd.ucar.edu. Forward and reverse name lookup do not give the same results: (laraine.unidata.ucar.edu) 608 % nslookup syrah.atd.ucar.edu Server: 128.117.140.62 Address: 128.117.140.62#53 Non-authoritative answer: Name: syrah.atd.ucar.edu Address: 128.117.78.2 Name: syrah.atd.ucar.edu Address: 128.117.80.2 (laraine.unidata.ucar.edu) 609 % nslookup 128.117.78.2 Server: 128.117.140.62 Address: 128.117.140.62#53 Non-authoritative answer: 2.78.117.128.in-addr.arpa name = syrah-78.atd.ucar.edu. Authoritative answers can be found from: 117.128.in-addr.arpa nameserver = dns2.itd.umich.edu. 117.128.in-addr.arpa nameserver = dns.ucar.edu. So, what is its _real_ name (result of a 'hostname') of your machine? >I've attached the ldmd.conf file, and you can see that we are >currently requesting only NEXRAD feeds. We need all of >the radars from regions 3 and 4, and six additional >radars outside those regions. If you have any suggestions >for improving the form of our requests, please let >me know. OK. Here goes. 1) We are asking all sites participating in the IDD (like syrah is) to report real time statistics. This is easily done by the addition of one 'exec' line in ~ldm/etc/ldmd.conf: exec "rtstats -h rtstats.unidata.ucar.edu" This exec line should be the last 'exec' line at the top of your file. If the result of a 'uname -n' on your machine does not return a fully qualified hostname (like syrah.atd.ucar.edu), then you need to edit your LDM-6 'ldmadmin' script to set the hostname correctly _before_ you start running LDM-6: change: chop($hostname = `uname -n`); # $hostname = "your.hostname.here"; to: # chop($hostname = `uname -n`); $hostname = "syrah.atd.ucar.edu"; We need the fully qualified hostname of each IDD participant in order to correctly process the real time stats that they be send in. For reference, real time statistics for LDM-6 sites participating in the IDD can be found in: http://www.unidata.ucar.edu/staff/chiz/rtstats Click on the 'Statistics by Host' link, and then the link for your machine (after it starts reporting stats, of course), and then either 'latency', 'log(latency)', 'volume', 'products', or 'topology'. The 'topology' link will show you how the data gets to your machine. The links that are machine names in that page give access to plots of differential latencies for the products in that feed (i.e., the latency from one machine to the next as opposed to the 'latency' link which gives overall latency). 2) You are requesting an NNEXRAD feed with two different request lines. In LDM-5 these two requests would be combined into a single request and sent to the upstream host. In LDM-6, however, these are not combined. This results in two rpc.ldmd processes on both your machine (probably no big deal) AND on the upstream feeder (could be a big deal depending on that system's load). It also results in the data being sent twice unless the request regular expressions are mutually exclusive (yours are). Your request lines are: request NEXRAD "^SDUS5[34]" thelma.ucar.edu request NEXRAD "^SDUS.. .* .* /pN..(CLE|ILN|RLX|GSP|FFC|JGX)" thelma.ucar.edu These can be combined into a single request as follows: request NNEXRAD "(SDUS5[34]|/pN..(CLE|ILN|RLX|GSP|FFC|JGX))" thelma.ucar.edu I always test regular expressions like this by using notifyme to the upstream host: notifyme -vxl- -o 3600 -f NNEXRAD -h thelma.ucar.edu -p "(SDUS5[34]|/pN..(CLE|ILN|RLX|GSP|FFC|JGX))" A review of the listing returned by notifyme will tell you that your request pattern is what you want or not. Please let me know if you have any questions about the information above. Tom >From address@hidden Fri May 9 13:05:11 2003 Hi Tom, Tom Yoksas wrote: > Hi Chris, > > >>Joe VanAndel forwarded your message regarding our LDM >>on syrah.atd.ucar.edu (a.k.a. ldm.atd.ucar.edu). > > > This machine is showing up in our LDM log files as > syrah-78.atd.ucar.edu. Forward and reverse name lookup do not > give the same results: > > [..nslookup results...] > > So, what is its _real_ name (result of a 'hostname') of your machine? The machine's hostname is 'syrah', but it's on two nets and also has a cname entry in DNS, so syrah has three fully qualified names: syrah.atd.ucar.edu 128.117.80.2 syrah-78.atd.ucar.edu 128.117.78.2 ldm.atd.ucar.edu -> syrah-78.atd.ucar.edu The current ldmadmin has: #chop($hostname = `uname -n`); $hostname = "ldm.atd.ucar.edu"; so you will see IP 128.117.78.2; a reverse lookup will give "syrah-78.atd.ucar.edu" and not "ldm.atd.ucar.edu". The idea was that with a cname, we could move the LDM arbitrarily to a different machine here and just change our cname entry, and not have to worry about upstream LDMs changing their "allow" entries. It violates the assumption that a forward then reverse lookup will leave you with the same name, though. For our current purposes, thelma is the only upstream server, so I've just changed to using "syrah-78.atd.ucar.edu". I've also turned on rtstats. > 2) You are requesting an NNEXRAD feed with two different request lines. > In LDM-5 these two requests would be combined into a single request > and sent to the upstream host. In LDM-6, however, these are not > combined. This results in two rpc.ldmd processes on both your > machine (probably no big deal) AND on the upstream feeder (could be > a big deal depending on that system's load). It also results in the > data being sent twice unless the request regular expressions are > mutually exclusive (yours are). > > Your request lines are: > > request NEXRAD "^SDUS5[34]" thelma.ucar.edu > request NEXRAD "^SDUS.. .* .* /pN..(CLE|ILN|RLX|GSP|FFC|JGX)" thelma.ucar.edu > > These can be combined into a single request as follows: > > request NNEXRAD "(SDUS5[34]|/pN..(CLE|ILN|RLX|GSP|FFC|JGX))" thelma.ucar.edu I'm all for keeping the number of processes down. The one-line request with your suggested regexp is in place. Thanks for the pointers, Chris