Date: Wed, 18 Nov 2015 13:07:09 +0300 From: Slawa Olhovchenkov <slw@zxy.spb.ru> To: Garrett Wollman <wollman@bimajority.org> Cc: freebsd-fs@freebsd.org, freebsd-stable@freebsd.org Subject: Re: Some filesystem performance numbers Message-ID: <20151118100709.GN48728@zxy.spb.ru> In-Reply-To: <21685.40094.453028.585630@hergotha.csail.mit.edu> References: <21685.40094.453028.585630@hergotha.csail.mit.edu>
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On Tue, Jan 13, 2015 at 05:30:54PM -0500, Garrett Wollman wrote: > I recently bought a copy of the SPECsfs2014 benchmark, and I've been > using it to test out our NFS server platform. One scenario of > interest to me is identifying where the limits are in terms of the > local CAM/storage/filesystem implementation versus bottlenecks unique > to the NFS server, and to that end I've been running the benchmark > suite directly on the server's local disk. (This is of course also > the way you'd benchmark for shared-nothing container-based > virtualization.) > > I have found a few interesting results on my test platform: > > 1) I can quantify the cost of using SHA256 vs. fletcher4 as the ZFS > checksum algorithm. On the VDA workload (essentially a simulated > video streaming/recording application), my server can do about half as > many "streams" with SHA256 as it can with fletcher4. For VDA recordsize=1M (or more) can give performance impcat in case saturated HDD by IOPS. > 2) Both L2ARC and separate ZIL have small but measurable performance > impacts. I haven't examined the differences closely. This is depend of fractions hot/warm/cold content. > 3) LZ4 compression also makes a small performance impact, but as > advertised, less than LZJB for mostly-incompressible data. > > I hope to be able to present the actual benchmark results at some > point, as well as some results for the other three workloads. > > -GAWollman > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"
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