> 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."    

> Also, VMWare does not (AFAIK) use ext3, but their own VMFS which is,
> among other things, cluster-aware (same storage can be shared by
> several VMware hosts).

I didn't know vmfs3 had extensions - I think vmfs3 is based on ext3.  At least, 
all the performance characteristics I've ever observed are on-par with ext3.  
But it makes sense they would extend it in some way.

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
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              • ... Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
              • ... Jim Klimov
              • ... Dan Swartzendruber

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