From owner-freebsd-questions Fri Apr 23 14:12:17 1999 Delivered-To: freebsd-questions@freebsd.org Received: from hostigos.otherwhen.com (dialin2017.pernet.net [205.229.2.17]) by hub.freebsd.org (Postfix) with ESMTP id 1866914BF2 for ; Fri, 23 Apr 1999 14:11:18 -0700 (PDT) (envelope-from mavery@mail.otherwhen.com) Received: from mail.otherwhen.com (mail.2.229.205.in-addr.arpa [205.229.2.19] (may be forged)) by hostigos.otherwhen.com (8.8.6/8.7.3) with ESMTP id QAA03394 for ; Fri, 23 Apr 1999 16:22:50 -0500 (CDT) Message-Id: <199904232122.QAA03394@hostigos.otherwhen.com> Received: from PORKY/SpoolDir by mail.otherwhen.com (Mercury 1.44); 23 Apr 99 16:08:39 -0600 Received: from SpoolDir by PORKY (Mercury 1.44); 23 Apr 99 16:08:33 -0600 From: "Mike Avery" To: freebsd-questions@freebsd.org Date: Fri, 23 Apr 1999 16:08:32 -0500 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: Re: Tape Backup Reply-To: mavery@mail.otherwhen.com In-reply-to: <199904232042.PAA04533@coffee.veryfast.net> References: X-mailer: Pegasus Mail for Win32 (v3.02b22) Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 23 Apr 99, at 15:46, John McNamee wrote: > On 23 Apr 99 at 13:22, Doug White wrote: > > > > Is there tape backup software for FreeBSD that in addition to backing > > > up UNIX will also backup NT Servers with Registry and Microsoft SQL > > > Server on a live system. I am using BE for NT currently but would like > > > to move yet another network function to BSD. > > > > Backing up SQL databases requires the backup program to have initmate > > knowledge of the DB system so it can handle the hot backup properly. I > > doubt it can be done from remote reliably. > > FYI... > > The way this is handled in the NT and Netware worlds is that the backup > software doesn't directly access the SQL database files. An agent (e.g. > daemon) runs on the database server machine, and it handles all the > details of database I/O to allow hot backup and restore. These agents are > all proprietary -- you need one specific both to the database and the > backup product. Database agents are typically a high priced add-on and > not part of the basic backup software. That's one approach. Stac's Replica, Columbia Data Product's SnapBack Live, St. Bernard's Open File Manager, and Computer Associates Open File Agent use variations on a different approach that is a bit more generic. I think Seagate Software has a similar approach, but I haven't looked at it. At the start of a backup (and they all seem to have different ways of detecting it), they setup a change file. When any disk activity occurs that would change the disk contents, the old data is written to the change file, and the new data hits the disk. If the backup program asks for data, it get the data from the change file if it's in there, otherwise it gets data from the disk. Any other program that asks for data gets it from the disk. This is tracked at the sector level. Some of them protect against file deletions - that is, if you delete a file, the file is moved to the change file. Some don't. I prefer to save the files. All these approaches *SHOULD* work with any data base. The files *SHOULD* be restorable in the same condition as when the backup started. Sometimes the implementations leave someting to be desired. Stac and Columbia bundle the open file product with their backup software. The other vendors sell it as their main product, or as an add-on to their backup products. Mike ====================================================================== Mike Avery MAvery@mail.otherwhen.com (409)-842-2942 (work) ICQ: 16241692 * Spam is for lusers who can't get business any other way * A Randomly Selected Thought For The Day: Every absurdity has a champion to defend it. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message