There are several major problems I can see with using dd as a backup tool --
- Because you are backing up the "free space" as well as the space occupied by the files, your backup will take extra long time. - You cannot do incremental backups. - Because you are backing up a system that is currently booted and operating, you are likely to miss important data that isn't always written to disk. For example, if you run a mysql server, the updates to the data in the database happen in realtime, yet the database file as written to disk is not necessarily usable at all, let alone up-to-date. - You are required to restore onto a disk with the same geometry, and it is often nice to alleviate yourself from this restriction. ---------------------------------------- There is one, very common oversight by people doing backups of their system -- Simply using tar, or dd, or dump is not necessarily good enough. You have to understand what applications are running, and follow that application's recommended backup procedure. The best example I can think of is mysql. Before backing up your system, if you run mysql, I would suggest running mysqldump to put the latest data into a file, and then run dump to backup the files. When you restore, you would use "restore" and then when you start the mysqld, you would need to re-import the mysqldump file. ---------------------------------------- Sharon, I hate to say it (because it is a lot of work) but I think the best backup method is this -- - First backup your applications to file, if applicable for the applications that you run. - Then backup the FS using dump When you need to restore, - Boot a rescue CD or install a minimal partition of a secondary linux - Repartition & format - Mount the destination partition and Run restore - Install the bootloader - Boot the OS that you are restoring. - Restore the applications, if applicable. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Metro Sent: Wednesday, August 10, 2005 7:04 PM To: L-bblisa Subject: Re: [BBLISA] Good way to recover Linux server Theo Van Dinter wrote: > snagao wrote: >> I know Linux doesn't have anything equivalent to AIX's mksysb >> command, but can someone please recommend a tool or method for me to >> back up the OS and recover it quickly for DR testing? > > I don't know of a "all in one" utility off the top of my head, I've > always either done dump or more likely tar of the files. Then on bare > metal recovery, you just boot into a rescue CD, make the partitions > and filesystems, untar, reinstall the boot loader, reboot. Instead of tar or dump, you can use dd to image the entire drive, including its partition table and boot sector, or an individual partition. Similarly Partimage (http://partimage.org/) will let you save a partition to a file with the added benefit that it intelligently skips over unused space. As above, you'll need to bootable rescue CD, such as SystemRescueCd (http://www.sysresccd.org/), in order to restore partitions on an unbootable system. Try reposting your query on the BLU (www.blu.org) discuss list, as you'll find a larger population of Linux users there. -Tom _______________________________________________ bblisa mailing list [email protected] http://www.bblisa.org/mailman/listinfo/bblisa -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.5/67 - Release Date: 8/9/2005 -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.5/67 - Release Date: 8/9/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.8/71 - Release Date: 8/12/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.8/71 - Release Date: 8/12/2005 _______________________________________________ bblisa mailing list [email protected] http://www.bblisa.org/mailman/listinfo/bblisa
