Multiple Archive Tapes
You can do 1 of 3 things. 1. Take your tape archive to another processor that has 2 tape drives and make a copy of it using dd if=tapedrive1 of=tapedrive2 ... etc 2. If you have enough disk space, do your archive to disk, then make copies to 2 tapes - 1 for storage, the other to keep on site. 3. Just go ahead and do back-to-back archives, assuming you have the time to fit in 2 archives. Don't worry about overwriting or removing logs. An archive does not destroy any log contents. Assuming that you are backing up your logical logs, you can restore from either archive, then roll forward using the tapes that contain the logical logs. All you might lose is the data that was in the logical logs that were not backed up at the time of the failure ( and that's assuming that the disk containing your logical logs was destroyed, and it's not mirrored ). For instance, assume the following: logical log 1 fills logical log 2 fills archive 1 begins logical log 3 fills logical log 4 fills archive 1 ends logical log 5 fills archive 2 begins logical log 6 fills archive 2 ends logical log 7 fills database crashes You may now restore from either archive 1 or archive 2. If you restore from archive 1, you will have the option to back up the logs beginning with logical log 3 or later. You select which log(s) to back up depending on what you have already backed up to tape and what is still on disk. ( Again, that assumes that your logs disk is available - incentive to do continuous logging! ). You then perform the restore and roll forward from the logs you backed up to tape. If you chose to restore from archive 2, you will be asked if you'd like to back up any of the logs beginning with log 6. You then do the restore and roll forward the logs as in the first example. The point is that the 2nd archive did nothing to erase or make unavailable logs 3, 4, and 5 for the first archive. I hope this helps. Mike Ballentine P.S. I like your signoff. --------------------------( Forwarded letter 1 follows )--------------------- >Date: Friday, 9 May 1997 2:53pm >Date:Fri, 9 May 1997 14:34:55 -0500 >From: hlt@napcc.aspca.org >X-Mailer: Mozilla 3.0 (X11; I; HP-UX B.10.20 9000/750) >MIME-Version: 1.0 >To: informix-list@rmy.emory.edu >Subject: Multiple Archive Tapes >Content-Type: text/plain; charset=us-ascii >Content-Transfer-Encoding: 7bit >Sender: informix-list-owner@rmy.emory.edu >Reply-To: Harold Trammel <hlt@napcc.aspca.org> >X-Informix-List-Id: <list.14430> We are running Online 5.0 on an HP-UX system which has only one DDS tape drive. We want to make two "identical" tape backups of our Online system. One tape is to remain on-site, the other off-site for security/disaster recovery. Our Online system is getting new data 16-20 hours out of each day. We cannot afford to take users off the database to let us do backups (that is one reason why we have Online). The problem is that in the 1-2 hours it takes for us to make one backup, the users have entered new data and the second tape will not contain the same data. In addition, the second backup will remove the logical log(s) that will have been created between the first and second backup. This can cause problems with restoration of the Online system. I cannot add a second tape drive for several reasons. How do others solve this problem? Thanks in advance for your assistance. -- Harold L. Trammel |"... encourage ASPCA/National Animal Poison Control Center | one another Phone:217/337-5030 x 260 Fax: 217/337-0599 | daily ..." - Heb 3:13