Date: Sat, 19 Jul 2014 15:57:37 -0400 From: Daniel Staal <DStaal@usa.net> To: freebsd-questions@freebsd.org Subject: Re: deciding UFS vs ZFS Message-ID: <578E7D82A34085A024A9BD33@[192.168.1.50]> In-Reply-To: <20140718180416.715cdc0b@gumby.homeunix.com> References: <20140713190308.GA9678@bewilderbeast.blackhelicopters.org> <20140714071443.42f615c5@X220.alogt.com> <53C326EE.1030405@my.hennepintech.edu> <20140714111221.5d4aaea9@X220.alogt.com> <20140715143821.23638db5@gumby.homeunix.com> <CALfReyf8Rg7rCcob4jSk9XbPLY0MpP52jno9vZ0GUFQGS0Vy-A@mail.gmail.com> <20140716143929.74209529@gumby.homeunix.com> <CALfReycWppVY5BYHeqvunvnUDtwPAke5vug0Kik2_JTnvvfArQ@mail.gmail.com> <20140718180416.715cdc0b@gumby.homeunix.com>
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--As of July 18, 2014 6:04:16 PM +0100, RW is alleged to have said: >> "I was really more interested in whether ZFS (with ARC) is faster than >> UFS with FreeBSD's own file caching. A lot of people say that putting >> an OS on SSD gives a significant speed-up. 16GB should be more than >> enough to keep the important system files in memory, so it sounds like >> smarter caching might be useful." >> >> If you want speed sure UFS is faster on the same machine, but that's >> because its doing less. > > Yes, I know ZFS has overheads, but ARC is potentially better than OS > caching. The question was whether, with a decent amount memory, ZFS can > actually be faster than UFS. --As for the rest, it is mine. Checking would take extensive work, and I think it would be *heavily* workload/hardware/tuning dependent, but I suspect there are probably cases where it would be. For a similar type of example: Turning on compression in ZFS can improve speed, depending on the data and the hardware. If it takes less time to compress/uncompress data than it does to write the difference to disk it speeds up; so with highly compressible data and light compression you often get higher speeds. There are several of that types of trade-offs available in ZFS, and you can tune for different uses. I don't think anyone has done comparisons, but it's probably possible that ZFS is faster under certain circumstances, even with a one-disk pool. Daniel T. Staal --------------------------------------------------------------- This email copyright the author. Unless otherwise noted, you are expressly allowed to retransmit, quote, or otherwise use the contents for non-commercial purposes. This copyright will expire 5 years after the author's death, or in 30 years, whichever is longer, unless such a period is in excess of local copyright law. ---------------------------------------------------------------
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