Date: Mon, 9 Aug 2010 17:12:21 +0200 From: Ivan Voras <ivoras@freebsd.org> To: Joshua Boyd <boydjd@jbip.net> Cc: freebsd-stable@freebsd.org Subject: Re: 8-STABLE Slow Write Speeds on ESXI 4.0 Message-ID: <AANLkTimuPnac_h-ipCyD76j%2B0HGttBxDYyTNdtdU0_sm@mail.gmail.com> In-Reply-To: <AANLkTimu2JoC6bmaBcSY3e5ovBPnwZ_s_zbRK=v8h7f6@mail.gmail.com> 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>
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On 9 August 2010 16:55, Joshua Boyd <boydjd@jbip.net> wrote: > On Sat, Aug 7, 2010 at 1:58 PM, Ivan Voras <ivoras@freebsd.org> wrote: >> >> On 7 August 2010 19:03, Joshua Boyd <boydjd@jbip.net> wrote: >> > On Sat, Aug 7, 2010 at 7:57 AM, Ivan Voras <ivoras@freebsd.org> wrote: >> >> >> It's unlikely they will help, but try: >> >> >> >> vfs.read_max=32 >> >> >> >> for read speeds (but test using the UFS file system, not as a raw >> >> device >> >> like above), and: >> >> >> >> vfs.hirunningspace=8388608 >> >> vfs.lorunningspace=4194304 >> >> >> >> for writes. Again, it's unlikely but I'm interested in results you >> >> achieve. >> >> >> > >> > This is interesting. Write speeds went up to 40MBish. Still slow, but 4x >> > faster than before. >> > [root@git ~]# dd if=/dev/zero of=/var/testfile bs=1M count=250 >> > 250+0 records in >> > 250+0 records out >> > 262144000 bytes transferred in 6.185955 secs (42377288 bytes/sec) >> > [root@git ~]# dd if=/var/testfile of=/dev/null >> > 512000+0 records in >> > 512000+0 records out >> > 262144000 bytes transferred in 0.811397 secs (323077424 bytes/sec) >> > So read speeds are up to what they should be, but write speeds are still >> > significantly below what they should be. >> >> Well, you *could* double the size of "runningspace" tunables and try that >> :) >> >> Basically, in tuning these two settings we are cheating: increasing >> read-ahead (read_max) and write in-flight buffering (runningspace) in >> order to offload as much IO to the controller (in this case vmware) as >> soon as possible, so to reschedule horrible IO-caused context switches >> vmware has. It will help sequential performance, but nothing can help >> random IOs. > > Hmm. So what you're saying is that FreeBSD doesn't properly support the ESXI > controller? Nope, I'm saying you will never get raw disk-like performance with any "full" virtualization product, regardless of specifics. If you want performance, go OS-level (like jails) or some example of paravirtualization. > I'm going to try 7.3-RELEASE today, just to make sure that this isn't a > regression of some kind. It seems from reading other posts that this used to > work properly and satisfactorily. Nope, I've been messing around with VMWare for a long time and the performance penalty was always there.
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