From owner-freebsd-scsi Mon Jan 31 5:54:28 2000 Delivered-To: freebsd-scsi@freebsd.org Received: from medicus.medicusnet.de (medicus.medicusnet.de [195.226.123.18]) by hub.freebsd.org (Postfix) with ESMTP id 1D8CF15045 for ; Mon, 31 Jan 2000 05:54:19 -0800 (PST) (envelope-from Stefan_Huerter@LU2.maus.de) Received: from medicus.medicusnet.de (root@medicus.medicusnet.de [192.168.1.1]) by medicus.medicusnet.de (8.8.8/8.8.7) with ESMTP id OAA06758 for ; Mon, 31 Jan 2000 14:54:01 +0100 Message-ID: <200001310445.p54310@lu2.maus.de> Date: Mon, 31 Jan 2000 03:45:00 -0000 From: Stefan_Huerter@LU2.maus.de (Stefan Huerter) Subject: hardware vs software stripping Organization: Quark Ludwigshafen 2 +49-6237-920345 To: freebsd-scsi@FreeBSD.ORG X-Gateway: Mauscon(0.9.4)/medicus.medicusnet.de, MausTausch X-Gateway-Admin: gatelu@medicus.medicusnet.de X-MAUS-X-Line: R+ Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Guckux Marc > website and searching all over the web to find a solution for > performing fast reads on an array of disks. The best choice seems > to be raid-0 for our database using postgresql. The alternatives > are either raid-1 which seems too wasteful on disks or raid-5 which > provides fault tolerance. This last option could substituted for a > tape backup and the possibility of a few minutes down time in case > of disk failure. Problem is: hardware or software? My opinion: RAID-5 and databases are two different worlds, it's useful for inexpensive storage and a database with very low-write accesses. The read-performance is so far OK, but the writes brake down the database performance. I recommand for all of my customers only RAID0+1, but there's a waste of storage (but necessary for reliability). And: RAID5 is no substitute for a Backup, these are definitily two worlds. > For hardware, I've been looking at the smartraid iv controller from > dpt There are other hardware-controllers on the market, eg IFT and others, beginning with 3 SCSI-channels, one for the host, 2 for the devices, built- in-Ram and more (supporting RAID0,1,5 and some more...). Or, to go back to the low-cost solution, there is Arena, SCSI-interface to the Host and working with IDE-drive with a few IDE-bus'. Bye Stefan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message