> -----Original Message----- > From: Alex Turner [mailto:[EMAIL PROTECTED] > Sent: Monday, April 18, 2005 5:50 PM > To: Bruce Momjian > Cc: Kevin Brown; pgsql-performance@postgresql.org > Subject: Re: [PERFORM] How to improve db performance with $7K? > > Does it really matter at which end of the cable the queueing is done > (Assuming both ends know as much about drive geometry etc..)? > [...]
The parenthetical is an assumption I'd rather not make. If my performance depends on my kernel knowing how my drive is laid out, I would always be wondering if a new drive is going to break any of the kernel's geometry assumptions. Drive geometry doesn't seem like a kernel's business any more than a kernel should be able to decode the ccd signal of an optical mouse. The kernel should queue requests at a level of abstraction that doesn't depend on intimate knowledge of drive geometry, and the drive should queue requests on the concrete level where geometry matters. A drive shouldn't guess whether a process is trying to read a file sequentially, and a kernel shouldn't guess whether sector 30 is contiguous with sector 31 or not. __ David B. Held Software Engineer/Array Services Group 200 14th Ave. East, Sartell, MN 56377 320.534.3637 320.253.7800 800.752.8129 ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
