From owner-freebsd-scsi Sun Jan 30 22: 3:17 2000 Delivered-To: freebsd-scsi@freebsd.org Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by hub.freebsd.org (Postfix) with ESMTP id BA1DE151AF for ; Sun, 30 Jan 2000 22:02:44 -0800 (PST) (envelope-from grog@freebie.lemis.com) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id QAA69237; Mon, 31 Jan 2000 16:27:31 +1030 (CST) Date: Mon, 31 Jan 2000 16:27:31 +1030 From: Greg Lehey To: Tom Cc: Marc Tardif , freebsd-scsi@FreeBSD.ORG Subject: Re: hardware vs software stripping Message-ID: <20000131162728.C68925@freebie.lemis.com> References: <20000131155356.B68925@freebie.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0pre2i In-Reply-To: WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Sunday, 30 January 2000 at 21:37:06 -0800, Tom wrote: > >>> Second, a DPT can't do RAID 5 + 0. It does the RAID 5 in >>> hardware. The RAID 5 you'll have to do in software. > RAID 0 >> >> Hmm. There's obviously a typo here, but I'm not sure how to correct >> it. I don't know the DPT implementation, but in Vinum RAID-5 implies >> striping. I'd be interested in hearing how DPT does it. > > RAID 5 on the DPT. RAID 0 in software. You misunderstand. RAID-5 in Vinum is implemented as a variant of RAID-0. Check http://www.lemis.com/vinum.html for details. > Create two or more RAID 5 volumes on the DPT, then strip all DPT > volumes into one big software volume using ccd (a lot of this > predates vinum). The RAID 0 can help insuluate you from the > generally crummy write performance of RAID 5. Not much. >>> An Infortrend (see below) can do a transparent copy-and-replace array >>> expansion. This however just leaves you with a bigger virtual disk. >>> FreeBSD has no way to grow a filesystem transparently. You can disklabel >>> the addtional space and make a new filesystem though. >> >> In a similar way, you can increase the size of a concatenated Vinum >> plex, or add another, larger plex to a volume. Both would increase >> the size of a volume. Some people also have tools for increasing the >> size of a ufs file system, but they still need work. > > These tools are also strictly off-line too. Solaris' growfs is very > disapointing in that all process that write just block until growfs is > completed. Depending on your application, that may be unacceptable. I can understand the problem. I don't think we'll get any better than that either. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message