From owner-freebsd-hackers Mon Mar 2 11:22:59 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA26335 for freebsd-hackers-outgoing; Mon, 2 Mar 1998 11:22:59 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from att.com (cagw2.att.com [192.128.52.90]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id LAA26324 for ; Mon, 2 Mar 1998 11:22:54 -0800 (PST) (envelope-from sbabkin@dcn.att.com) From: sbabkin@dcn.att.com Received: by cagw2.att.com; Mon Mar 2 14:17 EST 1998 Received: from dcn71.dcn.att.com (dcn71.dcn.att.com [135.44.192.112]) by caig2.att.att.com (AT&T/GW-1.0) with ESMTP id OAA09457 for ; Mon, 2 Mar 1998 14:21:36 -0500 (EST) Received: by dcn71.dcn.att.com with Internet Mail Service (5.0.1458.49) id ; Mon, 2 Mar 1998 14:23:52 -0500 Message-ID: To: tlambert@primenet.com Cc: shimon@simon-shapiro.org, wilko@yedi.iaf.nl, grog@lemis.com, jdn@acp.qiv.com, blkirk@float.eli.net, hackers@FreeBSD.ORG Subject: RE: SCSI Bus redundancy... Date: Mon, 2 Mar 1998 14:23:50 -0500 X-Priority: 3 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.0.1458.49) Content-Type: text/plain Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > ---------- > From: Terry Lambert[SMTP:tlambert@primenet.com] > > > > > I think Julian's SLICE code has something in that direction. > DPT > > > > supports INCREASING the size of a RAID-5 array by adding drives. > > > > > > How can that work? > > > > Something like > > - read N RAID blocks from K disks > > - compute new checksum for K+1 disks and write as less number > > of RAID blocks but each one of bigger size (K+1/K times) > > - add empty blocks at the end of RAID in the added space > > You would have to remember to grab the blocks to be relocated with > the same O(n) randomness as their allocation. 8-). > Huh ? Probably I've missed something about RAIDs. I've thought that, for example, RAID block 0 consists of blocks 0 of all the physical disks. And so on. And I've thought that RAID itself does not allocate any blocks, the upper level like filesystem or volume manager does it, RAID just makes chechsuming. Am I wrong again ? -SB To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message