Backup Issues
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- Which servers to backup
- Which directories/files to backup
- What is the Backup media
- Backup Failure Modes
- Testing Your Backups
- OffSite Backups
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| Backup Servers |
- Which Servers to backup
- Pull the ethernet cable to it....and see what happens..
- Backups should be on a different server than the server/data you are trying to backup
- protect against the server wiping itself out and its backup
- Backup all PCs on one LAN/hubb to a local backup server - minimize traffic
- Backup all Local backup servers to the other Building's Backup server and vice verss
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| Backup Directories |
- Most of the "System" directories and files are already on the installation cdrom
- Most of the "Updates" you applied are already scattered at the various mirrors on the internet
- Which directories to backup is dictated by the size and topology of your network
- Backup of a single server is significantly simpler than backup of different servers
- www, email, firewall, ftp servers, home servers, file servers, etc
- Which directories to backup is dictated by the partitions used to install
- move system config files into /etc or /usr/local/etc so that its backed up
- If you can recreate your entire system on another disk...you've selected the "right directories to backup"
- you should backup "user data"
- /root /etc /home /usr/local
- you should optionally backup log files and pending emails
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| Backup Media |
- The number of servers and size of your data dictates your backup media
- Backups onto floppy -- good for Full backups of /etc
- Backups onto Zip -- good for backups of 200Mb
- Backups onto CDR -- good for backups of 600Mb
- Backups onto DVD -- good for backups of 4GbMb
- Backups onto Tapes -- good for backups of up to 40-80Gb, and more with tape libraries
- Backups onto Disks -- good for 500Gb -- xxTeraByte Raid5 Backups
- NEVER backup your data to the same partition, nor same disk
- if you lose the disk...you do NOT have any backups
- Backups are best done to a DIFFERENT server
- protect your backups from hardware flakyness and random power surges etc
- Tape and CDR backup media REQUIRES you to change it daily/weekly...
- if you forget, you lose the previous backup... and you may also lose todays incremental backup data too
- You have to clean the tape head regularly
- You can lose one of the daily incremental tapes, or someone can walk out with your corp data
- Restoring a file from tape can be a slow process ( hours and hours )
- One 20Gb can hold about 1-2 months of full and incremental backup of another 20Gb disks depending on data amd backup methodology
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| Backup Failures |
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| Test Your Backup Methodology |
- Test your backup methodology before you need it restore/recover from a catastrophe
- Rebuild a new server with its data restored from backup only
- Pull the plug on the "main system" being backed up
- Check that your backups files contain all your directories you wanted
- Check that your incremental backups files are created daily
- Check that your full backup disks have enough space left for this coming full backup
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| Offsite Backup Methodology |
- In the Old days..
- There was typically only ONE building with all the mainframe computers
- Only one copy of all the 9-track tapes and removable 14" hard disk platters
- Tapes was cheap, while memory, disks and computers were extremely expensive
- In todays market..
- Most corporation have multiple buildings and PCs on each desk
- Corporate computer data is spread across the street and across the country and around the world
- Store Bldg_1 computer data in the OTHER building via your private VPN connection
- Office backups is still good for archives for the attorneys to review and stake their claims
- [ OLD ] Purpose of offsite backup
- In case of fire, earthquake, you'd have your important data stored safely and securely offsite
- You have an offsite archive of progress made on the projects
- Problem with offsite backups
- They have access to your passwd info
- They have access to all your confidential material
- It might take days/weeks/months to find or restore out-of-date data from offsite tapes
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