From owner-freebsd-hackers Tue Jun 13 21:44:13 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from obie.softweyr.com (obie.softweyr.com [204.68.178.33]) by hub.freebsd.org (Postfix) with ESMTP id 849BB37BD2C for ; Tue, 13 Jun 2000 21:44:08 -0700 (PDT) (envelope-from wes@softweyr.com) Received: from softweyr.com (Foolstrustident!@homer.softweyr.com [204.68.178.39]) by obie.softweyr.com (8.8.8/8.8.8) with ESMTP id WAA20073; Tue, 13 Jun 2000 22:44:00 -0600 (MDT) (envelope-from wes@softweyr.com) Message-ID: <39470DBA.D8045A1A@softweyr.com> Date: Tue, 13 Jun 2000 22:44:42 -0600 From: Wes Peters Organization: Softweyr LLC X-Mailer: Mozilla 4.7 [en] (X11; U; FreeBSD 4.0-STABLE i386) X-Accept-Language: en MIME-Version: 1.0 To: Jaye Mathisen Cc: hackers@FreeBSD.ORG Subject: Re: Has anybody looked at RAID-5 vinum performance on the "whole system"? References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Jaye Mathisen wrote: > > I was just curious what people's thoughts were on the potential "total > system throughput" (whatever you choose it to be), wrt using software > RAID. > > It would seem that software RAID would just kill big chunks of cache, > especially CPU cache, moving lots of data throught it to calcuate CRC's. > > perhaps the raid 1/0's would be fine, since the calcuation could be > ignored. Greg can probably give a better answer than I can, but one thing to be aware of is that host-based RAID, like Vinum, usually has access to a lot more processor and memory resources than hardware RAID controllers. My experience is limited to running an I/O bound, not compute-bound, server using both Vinum and a Mylex DAC1100 with 64MB RAM, using RAID-1. The system was a DELL 2400 with 2x 600 Mhz Pentium III. The application was a non-interactive web filter running over millions of web pages grabbed by a spider. The total throughput was significantly higher on the software RAID system. The application inherently sloshes through the caches anyhow, so little cache affect is achieved. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC wes@softweyr.com http://softweyr.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message