Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
I just started administering our university's LDM server, and my experience so far has ONLY involved migrating away from our physical server to running LDM on a virtual machine. I only understand LDM well enough to have set up a second, virtual server that does everything that our physical server does...but from my experience the only real concern is storage access times and what happens when the host server or storage servers go in to failover. We run around 100 VM's on three physical hosts with ESX (128gb ram, 4x4x2.5ghz AMD each) and three LeftHand VSA's (iSCSI over 1GB ethernet), all through a 2gig/sec link. Even with The only time I'm concerned that running a virtualized instance of our LDM server is when the network RAID storage needs to be re-striped between two nodes, and we have an inordinate amount of disk I/O on the backend. Otherwise, even iSCSI storage with network RAID is fast enough*, even though it is one of the slower solutions for storage in a virtual environment. *Fast enough...what does that mean? Myself not being a consumer of the LDM data, and since the college is fairly unpopulated during the summer...I can only assume because the load and I/O wait on the physical server is the same as the virtual server, the VM is performing okay. I'm still not entirely sure what metrics should be used to judge LDM performance, as the only complaint I've ever handled with the physical server is "missing data"...and I don't yet have enough people using our virtual LDM server to let me know how it's doing.. Bottom line is that the IT staff running the virtual infrastructure should have an idea of it's limits and be able to monitor if your LDM server is having an effect on the other virtual machines it is sharing resources with. They are offering it, and as long as it meets your needs you shouldn't be concerned...they'll let you know pretty quickly if it's adversely affecting others. In our case, it's a first come first serve scenario when it comes to load: since we're running LDM virtualized now, if other people add virtual servers and increase the load to a point that it does affect LDM, we'll be looking at the newcomers as "the problem", even if LDM proportionately uses more resources. It's hard to down the road say "hey, you can't virtualize LDM any more" if we've already ditched the hardware... --Alex Kubacki System Administrator College of Science IT Purdue University PS - It was also suggested to me to store the product queue in in a ramdisk to avoid excessive I/O, but I've yet to evaluate that possibility. On 6/16/11 11:49 AM, "Cotton, Benjamin J" <bcotton@xxxxxxxxxx> wrote: >Are you on this mailing list? If not, you should join and share your >experiences with running LDM on a VM. > > >---------- Forwarded message ---------- >From: Gilbert Sebenste <sebenste@xxxxxxxxxxxxxxxxxxxxx> >Date: Thu, Jun 16, 2011 at 10:07 AM >Subject: [ldm-users] LDM: Hey, hey, you, you, get onto my cloud >To: ldm-users@xxxxxxxxxxxxxxxx > > >Hey everyone, > >So I am trying to be wooed from our campus IT department to get onto >their cloud of servers. They say they could put on an any operating >system that I want,presuming Centos 6.X when it gets released...and if >so, they talk it to the moon: > >Up to 2 TB hard drive space >20 gigabit/sec throughput as of this fall to the Internet2/NLR >2 gb/sec to commodity Internet >24/7 monitoring as of this month >Now backed up fully by a UPS and a new generator >3 sources of A/C from 2 rooftop units > >Mirrored in two different places in town, one >on campus, one off-campus, and if one is destroyed, >I can be back up within 20 minutes > >So...has anyone actually done this, and is it worth it? I'm afraid to >slam everyone else in my "cloud". Or, is Mick Jagger right, should I >stay >off of this cloud? > >************************************************************************** >***** >Gilbert Sebenste >******** >(My opinions only!) >****** >Staff Meteorologist, Northern Illinois University >**** >E-mail: sebenste@xxxxxxxxxxxxxxxxxxxxx >*** >web: http://weather.admin.niu.edu ** >************************************************************************** >***** > >_______________________________________________ >ldm-users mailing list >ldm-users@xxxxxxxxxxxxxxxx >For list information or to unsubscribe, visit: >http://www.unidata.ucar.edu/mailing_lists/ > > >-- >Ben Cotton >Systems Research Engineer >IT Research Systems >Purdue University
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