Date: Wed, 25 Oct 2006 07:05:47 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Guido van Rooij <guido@gvr.org> Cc: Rink Springer <rink@freebsd.org>, freebsd-stable@freebsd.org Subject: Re: Gmirror performanc (was Re: Gmirror question) Message-ID: <20061025140547.GA94660@icarus.home.lan> In-Reply-To: <20061025132455.GA52157@gvr.gvr.org> References: <20061025100759.GA50625@gvr.gvr.org> <20061025101801.GE23885@rink.nu> <20061025103905.GB50937@gvr.gvr.org> <20061025104829.GA41873@hugo10.ka.punkt.de> <20061025132455.GA52157@gvr.gvr.org>
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On Wed, Oct 25, 2006 at 03:24:55PM +0200, Guido van Rooij wrote: > Anyway, I created a gm device and a partition. Now the read performance > is not what I'd expect. > I have the partition on two SATA devices on different controlers. > I get around 60MB/s for each disk. I can get that speed from both disks > simultaneously. > Now when I dd from the gm device, I don't get any speed higher than that. > I tried with -b split -s <various sizes>, -b round-robin, -b load. > (dd-ing as done with a bs of 1m; I see the transaction size is 128Kb, > unless the split method is used, in which case the transaction size > gies down. When round-robin is used, the transaction size is 128Kb/s, > but the number of transaction per second goes down.). Do not use dd to benchmark disks. It's not a viable method of benchmarking. Consider installing ports/benchmarks/bonnie++. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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