On Wed, Jul 18, 2007 at 10:03:00AM +0100, Heikki Linnakangas wrote: > Ron Mayer wrote: > > Seems Linux has IO scheduling through a program called ionice. > > > > Has anyone here experimented with using it rather than > > vacuum sleep settings? > > I looked at that briefly for smoothing checkpoints, but it was > unsuitable for that purpose because it only prioritizes reads, not writes. > > It maybe worth trying for vacuum, though vacuum too can do a lot of > writes. In the worst case, the OS cache is saturated with dirty pages, > which blocks all writes in the system. > > If it did prioritize writes as well, that would be *excellent*. Any > kernel hackers out there looking for a project?
My understanding is that FreeBSD will prioritize IO based on process priority, though I have no idea how it's actually accomplished or how effective it is. But if we put in special support for this for Linux we should consider FBSD as well. -- Jim Nasby [EMAIL PROTECTED] EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
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