vm.kmem_size_scale recommendation for ZFS

[Aristedes Maniatis]

Having just suffered from a FreeBSD 8.2 machine hit with the  "kmem_map too small" error [1], what is the current recommendation for a machine running RELEASE-8.2?

A. vm.kmem_size_scale=1 (this is the new default in 8-STABLE but 8.2-RELEASE had it set to 3)
B. vm.kmem_size_scale=0.66 (this is aligned with Pawel's recommendation of setting vm.kmem_size to 150% of your RAM. [2]
C. Leaving vm.kmem_size_scale alone and manually setting vm.kmem_size directly as Pawel is doing


Thanks
Ari Maniatis




[1] http://freebsd.1045724.n5.nabble.com/kmem-map-too-small-with-ZFS-and-8-2-RELEASE-td4029979.html
[2] http://blogs.freebsdish.org/pjd/2010/08/06/from-sysinstall-to-zfs-only-configuration


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Aristedes Maniatis
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