Gentoo Archives: gentoo-performance

From: "M. Edward (Ed) Borasky" <znmeb@×××××××.net>
To: gentoo-performance@l.g.o
Subject: Re: [gentoo-performance] LVM2 stripes and mirrors
Date: Thu, 12 Jul 2007 14:16:53
Message-Id: 46963746.6000003@cesmail.net
In Reply to: [gentoo-performance] LVM2 stripes and mirrors by Florian Philipp
Florian Philipp wrote:
> Hi! > > I've got two questions concerning LVM2. > > Number one: What stripesize parameter would you use? The manual of my > mainboard advises to use 64k for a RAID-0. Would that be useful for my > portage tree or a more conventional partition like /usr and /var? > > Number two is not really a performance issue but it's LVM2-related: > LVM2-mirrors need an extra log device but the man pages don't tell anything > about how large it has to be or if it can be a partition or loop device on > the same hdd as one of the mirrors. > > Thanks in advance! > > Florian Philipp
Sizing I/O subsystems is highly workload and filesystem dependent, and there's really no such thing as a one-size-fits-all quick answer. There are models and there are some really good I/O subsystem benchmarks you can use once you know what your workload characteristics are. I highly recommend the book "Storage Network Performance Analysis" http://www.amazon.com/Storage-Network-Performance-Analysis-Huseyin/dp/076451685X/ for the tools to do this. But one thing you can do first is to run your workload on a system and capture data with "iostat". If you don't have "iostat", you'll need to emerge "sysstat". The "iozone" benchmark is in Portage, as is bonnie++. The I/O benchmark I like most is IOMeter, but that requires a Windows system to run the control console and downloading a Linux agent from their web site. -- gentoo-performance@g.o mailing list

Replies

Subject Author
Re: [gentoo-performance] LVM2 stripes and mirrors Florian Philipp <f.philipp@××××××.de>