From owner-freebsd-hackers Thu Apr 6 21:53:28 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id VAA22430 for hackers-outgoing; Thu, 6 Apr 1995 21:53:28 -0700 Received: from cs.weber.edu (cs.weber.edu [137.190.16.16]) by freefall.cdrom.com (8.6.10/8.6.6) with SMTP id VAA22423 for ; Thu, 6 Apr 1995 21:53:27 -0700 Received: by cs.weber.edu (4.1/SMI-4.1.1) id AA18537; Thu, 6 Apr 95 22:45:59 MDT From: terry@cs.weber.edu (Terry Lambert) Message-Id: <9504070445.AA18537@cs.weber.edu> Subject: Re: large filesystems/multiple disks [RAID] To: babkin@hq.icb.chel.su (Serge A. Babkin) Date: Thu, 6 Apr 95 22:45:58 MDT Cc: freebsd-hackers@FreeBSD.org In-Reply-To: <199504071321.IAA00249@hq.icb.chel.su> from "Serge A. Babkin" at Apr 7, 95 08:21:30 am X-Mailer: ELM [version 2.4dev PL52] Sender: hackers-owner@FreeBSD.org Precedence: bulk > Yes. But mirroring gives additional throughput increase for reading > like stripping (and decrease for writing unlike it :-( ). But from > my experience big databases are much more often read than written, > aren't they ? Yes, but I'd expect the agregate performance to stay about the same. Large databases don't allow predictive read-ahead because they typically can't be modelled using a model that assumes locality of reference. Unless your cache is significantly large relative to your database. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.