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UsingBirchAndCedar

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Gijs Molenaar edited this page Feb 13, 2014 · 4 revisions

Hi all --

I've set up our two new machines, birch and cedar. Both have two dual-core Opterons (so 4 CPUs each) and 8 Gb of memory. Please note that they by no means supercede lofar9 and 10. If your development stuff runs fast enough on 9/10, then you won't see much of a gain on the new machines. People with large trees and/or datasets will see a significant performance gain running on birch or cedar. In addition, regardless of which machine you're on, you can get full benefit of the 8 extra CPUs every time you rebuild the system, see below.

Do note the following:

  1. Your login/password will work on the new machines. We won't impose any usage policy (for now, until some important project requires dedicated CPU power) except that people normally working on lofar9 are welcome on cedar, and lofar10 residents on birch.

  2. Your birch/cedar home directories are completely empty, you'll need to copy at least .bashrc, .cvspass and the like (e.g. from /net/lofar9/home/username) before you do anything else.

  3. You will need to check out and build a local Timba as per the usual procedure.

  4. The disk system on lofar9/10 is both larger and more fail-safe, and possibly even faster (hardware RAID-5 vs. a single SATA drive). Hence I encourage you to keep your "valuable" files where they are (lofar9/10) and use the new machines purely for horsepower.

  5. All disks are auto-mounted, so you can access your home directory on any machine from any machine via /net/hostname/home/username. All four machines are now linked up via a dedicated Gigabit switch, so nfs access should be very fast --- I assume you can leave your datasets on lofar9/10 and symlink to them from birch and cedar, with very little performance degradation, (although I haven't really tested this.)

  6. Builds on any host can use all available CPUs. Make sure your .distcc/hosts looks something like the following. For lofar9/10 I recommend:

localhost/2
birch/8
cedar/8
other-lofar/4

For birch or cedar:

127.0.0.1/8
birch/8         # or cedar/8 , if working on birch
lofar9/4
lofar10/4

Then, build with "make -j22" on lofar9/10, or "make -j24" on birch/cedar.

Have fun and please report any problems to me.

Cheers, Oleg

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