April 9th, 2009

epiphany, mathematics, lucid, logic, physics

Voice of America

I forgot how close I've lived to Voice of America's towers, or technically speaking "antennas", until checking out offroad trails at Google Maps.  Dad used to always take the road that ran next to the field, NC HWY 102, and I as a kid, it was in awesome site.  As an adult, I see how the government probably abuses these things, and how the media misinforms us about where such things actually exist, i.e. everyone says the site is in Greenville, but it's actually 20miles closer to the ocean.  Hopefully I can get closer to them with a camera before leaving here!
law, machina, groupthink, computers, science

Virtualization HyperDrive

Finally got my new virtualization design working.  I love how Winblows doesn't know it's infamous C: drive is actually an NFS share mounted for it by a Linux brain (ESX) and serviced by an array of disks managed by a Solaris box.  It could go in the opposite direction but I don't trust Microsoft disk management.  Let Winblows be a slave to the system ;) 

This was actually the best solution with the parts available.  The design allows each guest a dedicated LUN, where the array itself handles caching; the Solaris box merely interprets the file handles via NFS and offers a management interface for creating and sharing new LUNs.  ESX still creates a virtual disk for the guest (with its crappy filesystem, VMDK) and presents this disk to the guest OS; I expect that will be the only bottleneck.  It's always the weakest link, and in this case NetApp's Triantos has admitted that bandwidth is less of an issue than IO latency, i.e. ESX generates lots of little read/writes versus big ones.

So far, it seems just as responsive as the previous setup: direct connect SATA.  That is saying volumes.  The parts available for the new setup range from circa 2000 - 2004. The SATA stuff was all new, and had far fewer hoops: virtual SCSI drive -> guest OS VMDK -->> VMDK formatted volume -> SATA controller -> SATA drive.  The diagram below doesn't do justice for increasing to .5TiB, because the new sequence is: virtual SCSI drive -> NFS client kernel (ESX) -> NFS server module (Solaris) -> guest OS VMDK -->> UFS formatted LUN -> array controllers -> SCSI drive.  

and SUPER geek!