Sluglets meeting 30-05-03 Backup and Recovery Notes
Hi Guys here are the notes that I took from the last sluglet. Hopefully they make some sense: Definition: hot backup. A copy or backup running on a media which can be available quickly, ie archived on a secondary server or a hot swappable harddrive etc. Often used as a `disposable’ media, ie not kept safe at all costs. Limitation of using tape to backup modern quantities of data: often unable to hold anywhere near as much data as modern harddrives and drive arrays. Getting backup happening For businesses For offices sending copies to other branches or buildings. Also as a large scale option, having a remote system ready with recent data in a remote location for almost instant backup. Suggestion that ex-corporate backup drives can be available for reasonable prices on ebay. Tapes, especially used ones are not as reliable as DVD or CD. There was a warning against using tape compression. Data mirroring through net connection. Suggestion to use additional small servers for to create snap shots of a file tree so that deletions can be enforced when restoring data. Home Suggestion for home backup to use a portable drive bay. (Personal thought using something more flexible like a firewire connected external case). Suggestion to keep a copy of data off site. Locations may include close friends or family members. Backup Options: Historical reference to dump, the backing up of a file system (ie partition) rather than directories. Level 0 = full backup of a specified area Level 1 = backup files that have changed since the last level 0 Level 2 = backup of changed files since last level 1 Level 3-5 etc. 2-5 are incremental, quick backup, slow restore, higher risk of failure as # of media increase. Tapes have a limited life span. Differential backs up changed files since last level 0 backup. On linux likely backup areas include: /home the machine configuration (/etc) list of installed packages (some software is out there to produce a dump of them) /dev/conf ? Check Partitioning can be used to place data on a separate partition to make it possible to reinstall the distro without killind data. Placing on a separate drive also makes a drive failure less of a pain. Determine backup strategy based on size needs, how often the data is changed and the time and money that can be spent on it. Testing backup. Be sure that third parties can meet their claims Backup versus disaster recovery. A disaster is the complete failure of a system or environment. Hence a disaster recovery plan requires more resources than just backing up software, but can produce a quicker result in restoring entire systems. For Reference: Always Document procedures, including contact people, equipment location etc. Make sure hard copies are available Physical resistance to damage. Tapes are more resistant than hard drives in situations such as dropping them. For small amounts of data solid state media such as flash memory may be an option. Final comment: Data not backed up is almost guaranteed to be lost at some point... Remote storage with places like yahoo’s briefcase. LVM and EVS were mentioned, but not in detail. EVS extended volume ??? RAID ( drive mirroring, etc) can be used to recover from drive failure, however not useful for retreiving data thats been over written or deleted. snapshot (debian.net). Was mentioned -- SLUG - Sydney Linux User's Group - http://slug.org.au/ More Info: http://lists.slug.org.au/listinfo/slug
