On 11/8/2012 12:35 PM, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) wrote:
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
boun...@opensolaris.org] On Behalf Of Jim Klimov

the VM running "a ZFS OS" enjoys PCI-pass-through, so it gets dedicated
hardware access to the HBA(s) and harddisks at raw speeds, with no
extra layers of lags in between.
Ah.  But even with PCI pass-thru, you're still limited by the virtual LAN switch 
that connects ESXi to the ZFS guest via NFS.  When I connected ESXi and a guest 
this way, obviously your bandwidth between the host&  guest is purely CPU and 
memory limited.  Because you're not using a real network interface; you're just 
emulating the LAN internally.  I streamed data as fast as I could between ESXi and 
a guest, and found only about 2-3 Gbit.  That was over a year ago so I forget 
precisely how I measured it ... NFS read/write perhaps, or wget or something.  I 
know I didn't use ssh or scp, because those tend to slow down network streams quite 
a bit.  The virtual network is a bottleneck (unless you're only using 2 disks, in 
which case 2-3 Gbit is fine.)

I think THIS is where we're disagreeing:  I'm saying "Only 2-3 gbit" but I see Dan's email said 
" since the traffic never leaves the host (I get 3gb/sec or so usable thruput.)"  and  "No 
offense, but quite a few people are doing exactly what I describe and it works just fine..."

It would seem we simply have different definitions of "fine" and "abysmal."    
Now you have me totally confused. How does your setup get data from the guest to the OI box? If thru a wire, if it's gig-e, it's going to be 1/3-1/2 the speed of the other way. If you're saying you use 10gig or some-such, we're talking about a whole different animal.
zfs-discuss mailing list
  • Re: [zfs-discuss]... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
    • Re: [zfs-dis... Dan Swartzendruber
      • Re: [zfs... Edmund White
      • Re: [zfs... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
        • Re: ... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
          • ... Eugen Leitl
            • ... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
        • Re: ... Jim Klimov
          • ... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
            • ... Dan Swartzendruber
              • ... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
              • ... Dan Swartzendruber
              • ... Dan Swartzendruber
              • ... Dan Swartzendruber
              • ... Geoff Nordli
              • ... Dan Swartzendruber
              • ... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
              • ... Jim Klimov
              • ... Dan Swartzendruber
              • ... Ian Collins

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