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Re: Top level CONDUIT relay
- Subject: Re: Top level CONDUIT relay
- Date: Thu, 21 Jun 2007 10:23:14 -0400
Yes, I made the change to the LDM servers to test the shared memory
configuration.
# Setting SHMMAX Parameter 4 GB
kernel.shmmax = 4294967296
# getconf PAGE_SIZE
kernel.shmmni = 4096
kernel.shmall = 2097152
However, this doesn't explain the performance relief because... ldm
doesn't seem to be using shared memory, or at least not listed on the
table. Mr Cano thought LDM might be using this.
ldm1:~$ ipcs -a
------ Shared Memory Segments --------
key shmid owner perms bytes nattch
status
0x00000000 0 root 600 3976 4
dest
------ Semaphore Arrays --------
key semid owner perms nsems
------ Message Queues --------
key msqid owner perms used-bytes messages
Justin Cooke wrote:
> Chi,
>
> Has anything at all changed on ldm1 since yesterday? Starting at 04Z
> the feed on node6 improved dramatically, all other subscribers to ldm1
> also noticed improved performance.
>
> Justin
>
> Steve Chiswell wrote:
>> Justin,
>>
>> I noticed that the feeds from ldm1 dropped as you said. Do you know
>> if anything
>> changed related to that machine?
>>
>> I can add daffy back to ldm1 and see if things maintain their
>> performance, but
>> will wait to find out if any changes were made? Since ldm2 is still
>> lagging,
>> seems like it is not a network wide issue?
>>
>> Steve
>>
>> On Thu, 21 Jun 2007, Justin Cooke wrote:
>>
>>
>>> Steve,
>>>
>>> Looking at the graphs it appears that transfers improved greatly after
>>> 04Z today. I did a netstat on ldm1 and I still see where atm and flood
>>> are subscribing to it, same as yesterday.
>>>
>>> Although looking at the latency graphs you provide it looks like those
>>> subscribing to ldm2 are still seeing delays.
>>>
>>> http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?CONDUIT+atm.cise-nsf.gov
>>>
>>>
>>> Justin
>>>
>>> Steve Chiswell wrote:
>>>
>>>> Justin,
>>>>
>>>> I am receiving the stats from node6:
>>>> Latency:
>>>> http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?CONDUIT+node6.woc.noaa.gov
>>>>
>>>> Volume:
>>>> http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_vol_nc?CONDUIT+node6.woc.noaa.gov
>>>>
>>>>
>>>> The latency there to ldm1 is climbing on the initial connection, and
>>>> will start off by catching up on the last hours worth of data in the
>>>> upstream queue. After that, we can see what the latency is doing.
>>>>
>>>> Steve
>>>>
>>>> On Wed, 2007-06-20 at 12:43 -0400, Justin Cooke wrote:
>>>>
>>>>
>>>>> Steve and Chi,
>>>>>
>>>>> I tried to ping rtstats.unidata.ucar.edu but was unable to.
>>>>>
>>>>> Chi would you be able to set up a static route from node6 to
>>>>> rstats.unidata.ucar.edu like Steve mentions?
>>>>>
>>>>> I actually am unable to connect to ncepldm.woc.noaa.gov either.
>>>>> However
>>>>> I did set up a feed to "ldm1" and am receiving CONDUIT data
>>>>> currently.
>>>>>
>>>>> Steve how tough would it be to do the pqact step you mention and
>>>>> to get
>>>>> the stats reports from those if Chi is unable to get the static route
>>>>> going?
>>>>>
>>>>> Thanks for all the help,
>>>>>
>>>>> Justin
>>>>>
>>>>> On Jun 20, 2007, at 12:16 PM, Steve Chiswell wrote:
>>>>>
>>>>>
>>>>>
>>>>>> Justin,
>>>>>>
>>>>>> Is that box capable of sending stats to our rtstats.unidata.ucar.edu
>>>>>> host?
>>>>>> Eg, is it allowed to connect outside your domain?
>>>>>>
>>>>>> The ldm won't need to run pqact to test out the throughput and
>>>>>> netwrok,
>>>>>> but will need ldmd.conf lines:
>>>>>>
>>>>>> EXEC "rtstats -h rtstats.unidata.ucar.edu"
>>>>>> request CONDUIT ".*" ncepldm.woc.noaa.gov
>>>>>>
>>>>>> The pqact EXEC action can be commented out. The request
>>>>>> line will start the feed to ncepldm which flood.atmos.uiuc.edu is
>>>>>> pointing to, and showing high latency. If you are able to feed from
>>>>>> ncepldm
>>>>>> without the latency that outside hosts are showing, then it would
>>>>>> isolate the
>>>>>> problem further to the border of your network to the outside. If
>>>>>> you do
>>>>>> show similar latency, then it would either be the LDM configuration
>>>>>> itself, or the local
>>>>>> router that the machines are on.
>>>>>>
>>>>>> If you are able to send rtstats out to us, then we can monitor
>>>>>> stats on
>>>>>> our web pages.
>>>>>> Your network might require a static route be added for sending that
>>>>>> outside your domain (that would something your networking folks
>>>>>> would
>>>>>> know). The rtstats sends
>>>>>> a small text report about every 60 seconds, so not a lot of traffic.
>>>>>>
>>>>>> If you can't configure your host to send rtstats, then we could
>>>>>> create
>>>>>> q
>>>>>> pqact.conf action to file the .status reports and calculate the
>>>>>> latency
>>>>>> from those.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Steve
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, 2007-06-20 at 12:03 -0400, Justin Cooke wrote:
>>>>>>
>>>>>>
>>>>>>> Steve,
>>>>>>>
>>>>>>> If you provide us a pqact.conf I can have the box chi set up to
>>>>>>> feed
>>>>>>> off of ldm1 and see how its latencies are.
>>>>>>>
>>>>>>> Justin
>>>>>>> On Jun 20, 2007, at 11:36 AM, Steve Chiswell wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> Justin,
>>>>>>>>
>>>>>>>> Since the change at 13Z by dropping daffy.unidata.ucar.edu out
>>>>>>>> of the
>>>>>>>> top level nodes the ldm2 feed to NSF is showing little/no
>>>>>>>> latency at
>>>>>>>> all. The ldm1 feed to NSF which is connected using the
>>>>>>>> alternate LDM
>>>>>>>> mode is only devivering the .status messages its creates as all
>>>>>>>> the
>>>>>>>> other products are duplicates of products already being
>>>>>>>> received from
>>>>>>>> LDM2 and that is showing high latency:
>>>>>>>> http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?
>>>>>>>> CONDUIT+atm.cise-nsf.gov
>>>>>>>>
>>>>>>>> This configuration is getting data out to the community at the
>>>>>>>> moment.
>>>>>>>> The downside here is that it puts a single point of failure at
>>>>>>>> NSF in
>>>>>>>> getting the data to Unidata, but
>>>>>>>> I'll monitor that end.
>>>>>>>>
>>>>>>>> It seems that ldm1 is either slow, or it is showing network
>>>>>>>> limitations
>>>>>>>> (since
>>>>>>>> flood.atmos.uiuc.edu is feeding from ncepldm which is apparently
>>>>>>>> pointing to ldm1, there is load on ldm1 besides the NSF feed.
>>>>>>>> LDM2 is
>>>>>>>> feeding both NSF and idd.aos.wisc.edu (and Wisc looks good
>>>>>>>> since 13Z
>>>>>>>> as
>>>>>>>> well) so it is able to
>>>>>>>> handle the throughput to 2 downstreams, but adding daffy as the
>>>>>>>> 3rd
>>>>>>>> seems to
>>>>>>>> cross some point in volume of what can be sent out.
>>>>>>>>
>>>>>>>> Steve
>>>>>>>>
>>>>>>>> On Wed, 2007-06-20 at 09:45 -0400, Justin Cooke wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>> Thanks Steve,
>>>>>>>>>
>>>>>>>>> Chi has set up a box on the lan for us to run LDM on, I am
>>>>>>>>> beginning
>>>>>>>>> to
>>>>>>>>> get things running on there.
>>>>>>>>>
>>>>>>>>> have you seen any improvement since dropping daffy?
>>>>>>>>>
>>>>>>>>> Justin
>>>>>>>>>
>>>>>>>>> On Jun 20, 2007, at 9:03 AM, Steve Chiswell wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> Justin,
>>>>>>>>>>
>>>>>>>>>> Yes, this does appear to be the case. I will drop daffy from
>>>>>>>>>> feeding
>>>>>>>>>> directly and instead move it to feed from NSF. That will
>>>>>>>>>> remove one
>>>>>>>>>> of the top level relays of data having to go out of NCEP and
>>>>>>>>>> we can see if the other nodes show an improvement.
>>>>>>>>>>
>>>>>>>>>> Steve
>>>>>>>>>>
>>>>>>>>>> On Wed, 20 Jun 2007, Justin Cooke wrote:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> Steve,
>>>>>>>>>>>
>>>>>>>>>>> Did you see a slowdown to ldm2 after Pete and the other sites
>>>>>>>>>>> began
>>>>>>>>>>> making connections?
>>>>>>>>>>>
>>>>>>>>>>> Chi, considering steve saw a good connection to ldm1 before the
>>>>>>>>>>> other
>>>>>>>>>>> sites connected doesn't that point toward a network issue?
>>>>>>>>>>>
>>>>>>>>>>> All of our queue processing on the diskserver has been running
>>>>>>>>>>> without
>>>>>>>>>>> any problems so I don't believe anything on that system would
>>>>>>>>>>> impacting
>>>>>>>>>>> ldm1/ldm2.
>>>>>>>>>>>
>>>>>>>>>>> Justin
>>>>>>>>>>>
>>>>>>>>>>> On Jun 20, 2007, at 12:04 AM, Chi Y Kang wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>> I setup the test LDM server for the NCEP folks to test the
>>>>>>>>>>>> local
>>>>>>>>>>>> pull
>>>>>>>>>>>> from the LDM servers. That should give us some information /
>>>>>>>>>>>> network
>>>>>>>>>>>> or system related issue. We'll handle that tomorrow. I am a
>>>>>>>>>>>> little
>>>>>>>>>>>> bit concerned that the slow down all occurred at the some
>>>>>>>>>>>> time as
>>>>>>>>>>>> the
>>>>>>>>>>>> ldm1 crash last week.
>>>>>>>>>>>>
>>>>>>>>>>>> Also, can NCEP also check if there are any bad dbnet queues on
>>>>>>>>>>>> the
>>>>>>>>>>>> backend servers? Just to verify.
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Steve Chiswell wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks Justin,
>>>>>>>>>>>>> I also had a typo in my message:
>>>>>>>>>>>>> ldm1 is running slower than ldm2
>>>>>>>>>>>>> Now if the feed to ldm2 all of a sudden slows down if Pete
>>>>>>>>>>>>> and
>>>>>>>>>>>>> other
>>>>>>>>>>>>> sites add a request to it, it would really signal some
>>>>>>>>>>>>> sort of
>>>>>>>>>>>>> total
>>>>>>>>>>>>> bandwidth limitation
>>>>>>>>>>>>> on the I2 connection. Seemed a little coincidental that we
>>>>>>>>>>>>> had a
>>>>>>>>>>>>> show
>>>>>>>>>>>>> period
>>>>>>>>>>>>> of good connectivity to ldm1 after which it slowed way down.
>>>>>>>>>>>>> Steve
>>>>>>>>>>>>> On Tue, 2007-06-19 at 17:01 -0400, Justin Cooke wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>> I just realized the issue. When I disabled the "pqact"
>>>>>>>>>>>>>> process
>>>>>>>>>>>>>> on
>>>>>>>>>>>>>> ldm2 earlier today it caused our monitor script (in cron,
>>>>>>>>>>>>>> every 5
>>>>>>>>>>>>>> min) to kill the LDM and restart it. I have removed the
>>>>>>>>>>>>>> check
>>>>>>>>>>>>>> for
>>>>>>>>>>>>>> the pqact in that monitor...things should be a bit better
>>>>>>>>>>>>>> now.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Chi.Y.Kang wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Huh, i thought you guys were on the system. let me take a
>>>>>>>>>>>>>>> look
>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>> ldm2
>>>>>>>>>>>>>>> and see what is going on.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Justin Cooke wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Chi.Y.Kang wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Steve Chiswell wrote:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Pete and David,
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> I changed the CONDUIT request lines at NSF and
>>>>>>>>>>>>>>>>>> Unidata to
>>>>>>>>>>>>>>>>>> request data
>>>>>>>>>>>>>>>>>> from ldm1.woc.noaa.gov rather than ncepldm.woc.noaa.gov
>>>>>>>>>>>>>>>>>> after
>>>>>>>>>>>>>>>>>> seeing
>>>>>>>>>>>>>>>>>> lots of
>>>>>>>>>>>>>>>>>> disconnect/reconnects to the ncepldm virtual name.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> The LDM appears to have caught up here as an interim
>>>>>>>>>>>>>>>>>> solution.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Still don't know the cause of the problem.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Steve
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> I know the NCEP was stop and starting the LDM service
>>>>>>>>>>>>>>>>> on the
>>>>>>>>>>>>>>>>> ldm2
>>>>>>>>>>>>>>>>> box
>>>>>>>>>>>>>>>>> where the VIp address is pointed to at this time. how is
>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>> current
>>>>>>>>>>>>>>>>> connection to LDM1? is the speed of the conduit feed
>>>>>>>>>>>>>>>>> acceptable?
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Chi, NCEP has not restarted the LDM on ldm2 at all
>>>>>>>>>>>>>>>> today. But
>>>>>>>>>>>>>>>> looking
>>>>>>>>>>>>>>>> at the logs it appears to be dying and getting
>>>>>>>>>>>>>>>> restarted by
>>>>>>>>>>>>>>>> cron.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I will watch and see if I see anything.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Justin
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>> --
>>>>>>>>>>>> Chi Y. Kang
>>>>>>>>>>>> Contractor
>>>>>>>>>>>> Principal Engineer
>>>>>>>>>>>> Phone: 301-713-3333 x201
>>>>>>>>>>>> Cell: 240-338-1059
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>> --
>>>>>>>> Steve Chiswell <address@hidden>
>>>>>>>> Unidata
>>>>>>>>
>>>>>>>>
>>>>>> --
>>>>>> Steve Chiswell <address@hidden>
>>>>>> Unidata
>>>>>>
>>>>>>
--
Chi Y. Kang
Contractor
Principal Engineer
Phone: 301-713-3333 x201
Cell: 240-338-1059