Date: Wed, 6 Oct 2010 09:35:29 +0200 From: Torbjorn Kristoffersen <torbjoern@gmail.com> To: freebsd-fs@freebsd.org Subject: Re: Are any adjustments for ZFS necessary in 8.1 amd64? Message-ID: <AANLkTimZ_31wQ9xzeV%2Bhp1bM4RV_gMuBxSneGQLQo_%2BQ@mail.gmail.com> In-Reply-To: <4CABE9DC.7080601@DataIX.net> References: <162340.85805.qm@web113215.mail.gq1.yahoo.com> <4CABE9DC.7080601@DataIX.net>
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On Wed, Oct 6, 2010 at 5:15 AM, jhell <jhell@dataix.net> wrote: > On 10/05/2010 20:50, Trever wrote: >> Apologies if this has been answered previously, but I can't find definit= ive info. >> >> The FBSD handbook recommends a customized loader.conf when using ZFS (fo= r all architectures): >> vm.kmem_size=3D"330M" >> vm.kmem_size_max=3D"330M" >> vfs.zfs.arc_max=3D"40M" >> vfs.zfs.vdev.cache.size=3D"5M" >> >> Is this still true for the 8.1 amd64 release? =A0I've read various place= s that it is not and that handbook is NOT up-to-date. =A0Out of the box, am= d64 8.1 ZFS so far "just works" without any customizations other than to ma= ke sure it turns on at reboot. =A0But systems are fairly quiescent, we have= not gone to production yet. >> >> In addition to the handbook recommendations, are there 8.1 amd64 tunings= that should be done for a vanilla server? =A0(Will be imap server, actuall= y.) >> >> Without tuning as per above, I see this on our systems (sysctl -a): >> vm.kmem_size: 8318648320 >> vm.kmem_size_max: 329853485875 >> vfs.zfs.arc_max: 7244906496 >> vfs.zfs.vdev.cache.size: 10485760 >> >> Our systems have 24 GB of RAM. >> > > With the amount of RAM that you have available in your system I would > not recommend using the above values that you quoted from the Wiki. > Those values from the wiki IIRC were based on a i386 system that has > less than 1G of RAM and were used as an example more than a definitive > tuning to achieve better performance. > > With all the available configurations that are possible with a ZFS based > FreeBSD system I would suggest that you try out the defaults and move > from that point onward before you try tuning for a specific scenario. It > will be best to have a definitive starting point at which you can always > refer back to in your performance testing. > I've got the same setup except 8GB of memory. I'd also like to tune as best as I can, but I'm uncertain of how far I should try to go. It's a production system so I'm playing it a bit careful. Using default settings now, but I'm also interested in better performance. TK
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