North American Network Operators Group|
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RE: availability and resiliency
> >Hosts meeting three nines, or better, typically have redundant power > >supplies and integrated UPS, bootable RAID for the OS, > redundant NICs, > >and SMP CPU configurations. > > um...is an smp cpu configuration really going to help your uptime? or > are there operating systems or hardware out there that can say to > themselves "hmph! cpu 2 seems not to be working correctly...i'd > better spin it down." That is a natural function these days. Fail-safe to the "off" state. Most SMP OS's can recognise when one, out of an SMP CPU set, goes down. > just for fun a few years back i decided to check if the sun e4000 we > had had hot-swappable cpus (i figured it didn't, but why not try it?) > and i pulled one of the boards. it didn't like it too much. None of what I claimed is required to be hot-swappable to get 99.9%. Enough online hot-spares will keep the system up long enough so that you can replace the entire box. 99.9% allows over 8 hours per year outage. You should be able to swap out a host in less than 0.5 hours.