Date: Mon, 9 Aug 2010 18:38:15 +0200 From: Ivan Voras <ivoras@freebsd.org> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: Joshua Boyd <boydjd@jbip.net>, freebsd-stable@freebsd.org Subject: Re: 8-STABLE Slow Write Speeds on ESXI 4.0 Message-ID: <AANLkTinVCZLHqqTGiq=Je4byrvwVy-jbXZ6GizhOV3Xp@mail.gmail.com> In-Reply-To: <20100809161124.GA4618@icarus.home.lan> References: <AANLkTi=FNZ%2B=4yMPJBu%2BucGJiHqwMwQvoGcgqB%2BtPJF2@mail.gmail.com> <i3jhn0$ovp$1@dough.gmane.org> <AANLkTik%2BS2fe-sS242OXQprsEA4Oh4t6-CvBCuBCASz7@mail.gmail.com> <AANLkTimMA6OQKt-d6ecM=GmG2ciBTis-nHNovEwvjCB-@mail.gmail.com> <AANLkTimu2JoC6bmaBcSY3e5ovBPnwZ_s_zbRK=v8h7f6@mail.gmail.com> <AANLkTimuPnac_h-ipCyD76j%2B0HGttBxDYyTNdtdU0_sm@mail.gmail.com> <20100809161124.GA4618@icarus.home.lan>
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On 9 August 2010 18:11, Jeremy Chadwick <freebsd@jdc.parodius.com> wrote: > I thought Intel VT-d was supposed to help address things like this? Probably - http://www.intel.com/technology/itj/2006/v10i3/2-io/7-conclusion= .htm says it should help unmodified guests, but I don't know for sure. I do know that Nehalems run faster on VMWare, probably because "nested paging" or whatever it's called helps context switches on syscalls. > I can confirm on VMware Workstation 7.1, not ESXi, that disk I/O > performance isn't that great. =C2=A0I only test with a Host OS of Windows= XP > SP3, and for the Guest OS's hard disk driver use the LSI SATA/SAS > option. =C2=A0I can't imagine IDE/ATA being faster, since (at least > Workstation) emulates an Intel ICH2. Yes, disk IO was always slow with VMWare. VirtualBox cheats by emulating ATA controllers (ICH6) instead of SCSI and turning on disk cache - it's noticably faster than VMWare. > I was under the impression that ESXi provided native access to the > hardware in the system (vs. Workstation which emulates everything)? I think it can be configured this way, but then you'd need a separate LUN for the VM drive, bypassing vmware's usual storage (vmfs) and all the goodies that come with it. OTOH, there are paravirtualized drivers for Linux and Windows in 4.0 which should help, but I haven't tried them yet. > The controller seen by FreeBSD in the OP's system is: > > mpt0: <LSILogic SAS/SATA Adapter> port 0x4000-0x40ff mem 0xd9c04000-0xd9c= 07fff,0xd9c10000-0xd9c1ffff irq 18 at device 0.0 on pci3 > mpt0: [ITHREAD] > mpt0: MPI Version=3D1.5.0.0 > > Which looks an awful lot like what I see on Workstation 7.1. > > FWIW, Workstation 7.1 is fairly adamant about stating "if you want > faster disk I/O, pre-allocate the disk space rather than let disk use > grow dynamically". =C2=A0I've never tested this however. Yes, this statement has always been true. > How does Linux's I/O perform with the same setup? I've tested Linux, Windows and FreeBSD on VMWare 3.5 last year and the results (IOPS) were: ESXi-FreeBSD 174 ESXi-Linux 221 ESXI-Windows 98 Xen-FreeBSD 72 Xen-Linux 148 Xen-Linux-PV 244 HyperV-FreeBSD 61 HyperV-Linux 69 HyperV-Windows 58 (I couldn't get Windows to run on Xen; "Linux-PV" is Linux as paravirtualized Xen guest).
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