[ILUG] benefits of raw i/o

[David Murphy]

Quoting <20000614113133.T1129 at digiserve.ie>
by "John P. Looney (Kate)" <jplooney-ilug at online.ie>:

> Compare giving it ten or a hundred raw disks, vs. making one big LVM
> partition, and sitting it on that. That said, no one would do that
> anyway, they'd make up loads of different partitions, ones for
> indexing, data, system and tempspace etc. so you would wonder is
> managing disks for a database ever easy.

Actually, you can take a hundred disks, stripe 'em up with your LVM,
and present raw LVM devices to the database to work with. You
essentially always run an LVM, and choose wether to run raw over LVM
or filesystem over LVM

> No, but they want to get performance down to something like raw i/o,
> without the headaches. There has to be some reason people pay £16k a
> machine for a veritas filesystem & LVM.

We've just taken delivery of one of our clusters, so I'll see if we
can fit a few VxFS v UFS benchmarks into our testing.

-- 
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