Sunday, November 16, 2008

backup types

Introduction

”Oh no, the hard disk crashed, all data is gone, what do I do now?” Recognize this? I hope not. Every administrator should have backed up all the data. And to do that we need some kind of software (ok, we can do it manually by using ctrl+c and ctrl+v, but do you want to do that?). The backup utility in Windows Server 2003 is such software. And it’s better then ever now, with things like Open File Backup (files can be accessed by users the same time it’s backed up). The storage medium can be a logical drive, such as your hard disk, a removable drive, or a library with disks or tapes controlled by a robot. Read on and find out what’s new, how you perform backups and how it works.

What is backup?

Before we start with the actually backup we must know what we are doing. This section will give you all the information you need to understand how backup works.

Types of backups

  • Normal backup
    The normal backup is…normal (surprised?). So, what does this mean? It simply means that it copies all the files you have marked to be backed up, and marks the files as having been backed up. You also only need the most recent copy of the backup file (other types of backups requires several files, see below) to restore. This type is usually what you use the first time you backup files.
  • Incremental backup
    The incremental backup backs up only those files that have been created or changed since last incremental or normal backup. It also marks the files as having been backed up. A combination of Normal backups and Incremental backups is common, and also a very good combination. It also requires the least amount if storage space and is fast for backing up the data. The disadvantage of this is that it’s time-consuming to recover files, simply because you need the last normal backup set and all incremental backup sets, which can be stored on several backup drives or tapes.
  • Differential backup
    The differential backup is similar to the incremental backup and only copies files that have been created or changed since the last normal or incremental backup. No, it wasn’t a typo, it doesn’t check if a differential backup has been run. This is because differential backups does not mark files as having been backed up. A combination of differential backups and normal backups is more time-consuming concerning the backup part then the incremental + normal backups are. But on the other hand it is faster to restore data because all you need is the last normal backup and the last differential backup.
  • Copy backup
    A copy backup copies all the files you have selected, but does not mark the files as having been backed up. This backup type is useful when you must backup single files between normal and incremental backups because it does not affect these operations.
  • Daily backup
    The daily backup copies all the files that you have selected that have been modified on the day, without marking the files as having been backed up.

Volume Shadow Copy Technology

This is a new technology in Windows Server 2003 that did not exist in Windows 2000 Server. This technology is used to create a copy of the original volume at the time a backup is initiated. Data is then backed up from the shadow copy instead of the original volume. By doing this, all activity such as file changes, will not affect the backup, because it is using the shadow copy instead, which is not changed. So with this new feature users can access files during a backup, files are not skipped because they were in use, files open appears to be closed.

You should use Volume Shadow Copy, but you can disable it. The only time when you want to disable it is when you don’t have enough free disk space. As you can imagine you need as much extra disk space as the file you will backup uses. This consumption of disk space is however temporarily and will be free when the backup is completed.

If sufficient temporary disk space is not available Windows Server 2003 cannot complete shadow copy and the backup will skip open files.

To use this feature you must use NTFS as file system.

Volume Shadow Copy does not mean that you from now on can backup when the server usage is high. You should always backup when it’s low, for example at nights and weekends.

[Volume Shadow Copy can be used for several other things. In this text I’m covering the backup part of Volume Shadow Copy.]

Permissions

Not everyone can backup files and folders and you must have certain permission to do this. To be able to backup any file and folder on a local computer you must be an administrator or a backup operator in a local group on that computer. Likewise, to be able to backup any computer in a domain you must be administrator or backup operator on the domain or a domain with which they have a two-way trust relationship.

You can however always backup files and folders for which you have ownership of or one or more of the following permissions for the file and/or folder: Read, Read and execute, Modify, Full Control.

You can also be limited in the backup because of disk-quota restrictions that may restrict your access to the hard disk. To check this, right click the disk you want to save the data to and click Properties. Then click the Quota tab.

Good practice is to limit access to a backup file so only administrators and the owner (the one who created the backup file) is able to restore files and folders. This is available as an option during the backup wizard.

System state data

You can choose to do a System State backup, and this is very important if you want to be able to get a functional system in the event of a crash. This table shows which components that are backed up on a System State backup.

Component Included in System State Backup
Boot files and system files Yes
Registry Yes
COM+ Yes
System files under Windows File Protection Yes
Active Directory, directory service If it’s a domain
SYSVOL directory If it’s a domain controller
IIS Metadirectory If it’s installed
Certificate Services database If it’s a Certificate Services server
Cluster Service information If it’s within a cluster

You don’t have to know which of these components to backup. The Backup Utility included in Windows Server 2003 will choose this when you perform a System State backup. Likewise you cannot choose which components to restore; all the System State data will be restored. This is due to dependencies among the components. You can however restore the System State data to an alternative location. This does not mean that you can restore it to another computer and think it will work as the one you backed up. Not all data is restored when you restore to an alternative location. Only the components System boot files, registry files, SYSVOL directory files and Cluster database information files will be restored.

Restore system state data

If you are running in a non-domain environment all you have to do is follow the restore wizard (more about this later). But if you have to restore a Domain Controller it is not that simple. There are three different restore methods:

  • Primary restore
  • Normal restore
  • Authoritative restore

Depending on what you have to restore, if it must be restored to other Domain Controllers, or if you have more then one Domain Controller you use different methods.

  • Primary restore
    This is the type you should use when all Domain Controllers are lost and you are building up the domain from backup. But you should only use this when restoring the first replica set (SYSVOL and File Replication Service is example of replicated data sets). This is also the type you use when restoring a standalone Domain Controller.
  • Normal restore
    When doing a normal restore, Backup is working in nonauthoritative mode. That means that any data (including Active Directory objects) will have their original sequence number. This is the number AD replication uses to detect if there are any new objects to replicate to other servers. So when you use Normal restore any data will appear as old and will therefore not replicate to other servers. If newer data is available, it will of course replicate to the restored server. This method is used when restoring all but the first replica set and when restoring a single domain controller in a replicated environment.
  • Authoritative restore
    This is the third method. To perform an authoritative restore you have to run a utility called Ntdsutil. This must be run after you have restored the System State data, but before you restart the server. When you perform this kind of restore the sequence number of Active Directory objects are changed so that it has a higher number. This will ensure that any data you restore will be replicated (because Active Directory replication thinks it’s new). This is a little bit difficult to understand, but if you compare this to Normal restore, Normal restore will always mark objects as old, and authoritative restore will always mark objects as new. So simply said, use Authoritative restore when you have changed something and the change has been replicated to all other servers and you want to undo the change.

Remember: You must start a Domain Controller in Directory Services Restore Mode (press F8 during startup) to be able to restore System State data on a Domain Controller.

Backup data

We will use this backup scheme to create our backups.

Day Type of backup
Friday night Full backup (normal)
Saturday night Incremental, files and folders only
Sunday night Incremental, files and folders only
Monday night Incremental, files and folders only
Tuesday night Incremental, files and folders only
Wednesday night Incremental, files and folders only
Thursday night Incremental, files and folders only

Designing a good backup scheme is not always as simple as you might think. Questions like, what should I backup and when should I back it up occurs. The answer to these questions varies for every network and every server. Say that you will back up a Domain Controller and you add objects to Active Directory all the time. Then the above scheme would not be recommended. You’ll have to backup System State data at least one more time during the week (if not every day). The above scheme does likewise not have to apply web servers. You’ll have to find out when the load is as low as possible on the web server and use this information to find out what kind of backup scheme you want to use. Here are some general rules:

  • Backup when the load is as low as possible
  • If System State data is changed frequently, back it up more often
  • If files and folders are changed often, perform Full Backup more often
  • You will most likely have to perform backups beside this scheme. When doing this, if it is possible, do not use Full Backup or Incremental Backup because it can disturb the normal backup scheme (files are marked as already backed up). Sooner or later you won’t know where files are and it can be very time-consuming to restore.
  • Consider what you think is most important, a fast backup or to be able to restore fast, you cannot have both these features.
  • Click Start->Run and type ntbackup
  • Click the Advanced Mode link
  • Click Backup Wizard (Advanced)
  • Click Next
  • Make sure Back up everything on this computer is selected and click Next
  • We will backup to a file, you can place it wherever you want, just make sure you name it Friday and click Next
  • Click Advanced
  • Make sure Normal is selected as type of backup and click Next
  • Check the box Verify data after backup and click Next (You will most likely have errors when the backup is completed and verified. This is because System State data is changed all the time. If there are too many errors, there might be problems with the file you are using to back up data.)
  • Click Replace the existing backups and click Next
  • Click Later and in the Job Name box type Friday Nights, click Set Schedule
  • In Schedule Task select Weekly and as Start time 11:00 PM (or whenever you want the backup to be scheduled). Make sure it’s set to run every 1 week and on Fridays. Click OK
  • You will be prompted to run the task as a user. Use a user with privileges to backup data.
  • Click Next
  • Click Finish

The Backup Wizard should close and you should be back in the Backup Utility. You can now verify that the backup is scheduled by clicking on the Schedule Jobs tab.

In case you want to edit the backup you can do it from here. Just click the backup symbol on the day you want to edit.

  • Click the Welcome tab and start the Backup Wizard again.
  • Click Next
  • Select Backup selected files, drives or network data and click Next
  • Expand My Computer in the left pane and select all drives (in my case C: and D:) and click Next
  • Name it Monday and click Next
  • Click Advanced
  • Select Incremental as type of backup and click Next
  • Check the box Verify data after backup and click Next
  • Click Replace the existing backups and click Next
  • Click Later and in the Job Name box type Monday Nights, click Set Schedule
  • In Scheduled Task select Weekly and as Start time 11:00 PM (or whenever you want the backup to be scheduled). Make sure it’s set to run every 1 week and on Mondays.
  • Click Advanced and set the Start Date the same day as when the full backup will run. In my case that is January 03, 2003, so that is the start date I choose. Click OK, click OK
  • You will be prompted to run the task as a user. Use a user with privileges to backup data.
  • Click Next
  • Click Finish

Use the steps above to create incremental backups for the other five days of week. Of course all this can be done by writing a script, but I’ll leave that for now. And again, this is only a suggestion for a backup strategy. A backup strategy varies from company to company and it is not something you develop in one hour. You must analyze and find out what fits your company best. Also remember that if you followed the steps above, you will only save the backup files for a week. This is probably not what you want, and you have to schedule a script to move the files every week.

Where are the log files?

Of course you should read the log files so you are sure that the backup was successful. You do this be looking in Event Viewer for error messages, and you can also read a complete report by clicking Report on the Tools menu. If you want to log more or less, take a look in the Options on the Tools menu, and click on the Backup Log tab.

Restore data

It’s Wednesday, and you discover that an important file is corrupt. The question is, how do I restore the file from a backup? Well, it’s quite simple. The first thing we have to do is locate where the file are. If we know where on the disk it’s supposed to be, we can start from the latest incremental backup (Tuesday) and try to find it. If it’s not there, it means that the file was not altered, and we have to try the next file (Monday). On the other hand if we do not know where the file is, we have to restore the full backup file (Friday), find the file, and then find out if there is a newer version.

  • If the Backup Utility is not open, open it and click on the Advanced Mode link.
  • Click Restore Wizard
  • Click Next
  • Expand Tuesday.bkf, find the file you want to restore and check the box in front of the file. In my case it is 0055.txt in D:\sql
  • Click Next
  • Click Advanced
  • Select Single Folder. This is because I am only restoring one file, and I don’t want to restore it to the original location. If I choose Alternate Location it will keep the folder structure (in my case it will create the folder sql). Usually you will use Alternate Location when restoring files.
  • In Folder Name type where you want to restore the file (in my case c:\restore) and click Next
  • Select Leave existing files and click Next
  • Make sure Restore security settings and Preserve existing volume mount points are selected and click Next
  • Click Finish

That’s it! The file is restored.

You use the same process to restore System State data. Just remember that if you are restoring the System State data on a Domain Controller you must start the computer in Directory Services Restore Mode, which you access be pressing F8 when the computer is starting. And if you want to perform an Authoritative restore, remember to run ntdsutil before restarting the computer. More info about the ntdsutil can be found by typing ntdsutil /? in a command prompt.

Use the Restore and Manage Media tab

This is the tab where you format tapes, mark a tape as free, delete catalogs etc. And everything is very simple to do, just right click the object you want to do something with, and choose what you want to do.

Advanced Options

There are a lot of other options you can set to get the Backup Utility to work as you want. You access this from the Tools menu and then click Options. I will not write about everything here, instead I recommend you take a look there and if there is some option you do not understand, use the ? in the upper right to get more info about it.

Recovery Console

When nothing else works, Recovery Console saves you. You can use Recovery Console when you cannot boot into safe mode to read and write data (including NTFS) on local drives, enable and disable services, and many other things.

You can start the Recovery Console in two ways:

  • Boot the Windows Server 2003 CD and start the setup. When the text-based setup begins follow the prompts and choose recover by pressing R
  • Select Recovery Console from the list of available Operating Systems. To do this you must run a x86-based computer and install Recovery Console.

When you have started the Recovery Console, you will have to choose which Operating System to recover (if you are multi-booting). After that you will be prompted for the password for the administrator account. When you are logged on you will get a console from which you perform all tasks. This console is very similar to the command prompt in Windows Server 2003. The only command you have to remember is help. By writing that you will get a list of available commands to use. If you don’t know how to use a command, write the command name followed by /? . To exit the Recovery Console, write exit.

Install Recovery Console

You can only install the Recovery Console on a x86-based computer.

  • Click Start and then Run
  • Type (where x is the CD-ROM drive letter) x:\i386\winnt32.exe /cmdcons
  • Follow the wizard

Remove Recovery Console

  • Open My Computer and double click the hard drive on which you installed the Recovery Console
  • Click on Tools->Folder Options
  • Click on the View tab, check Show hidden files and folders and clear the Hide protected operating system files check box
  • At the root directory delete the folder Cmdcons and the file Cmldr
  • Right click My Computer and click Properties
  • Click on the Advanced tab and under Startup and Recovery click the Settings button
  • In System startup click the Edit button. This will display boot.ini in Notepad
  • Remove the entry for Recovery Console, it will look like: C:\cmdcons\bootsect.dat=”Microsoft Windows Recovery Console” /cmdcons
  • Save the file

Remember that the boot.ini is a very important file, and if you modify this incorrectly you can cause the computer to not boot up.

Automated System Recovery

Do you remember Emergency Repair Disk (ERD)? Forget about it. Well, ok, not yet, you have probably still some Windows 2000 Servers. But ERD is replaced by Automated System Recovery (ASR) in Windows Server 2003. ASR is a last resort and should only be used when options like Safe Mode and Last Known Good Configuration fails. ASR consists of two parts – backup and restore. The backup part can be accessed through the Automated System Recovery Preparation Wizard in the Backup Utility. This wizard backs up the System State data, system services and all disks associated with the operating system components. It also creates a floppy disk that you should store in a safe place. This floppy disk contains for example information about the backup.

When recovering by using ASR it will use the floppy disk to read the disk configuration and restore the disk signatures, volumes and partitions that is required to start your computer. ASR then installs a simple installation of Windows and automatically starts to restore from the backup ASR created in the wizard.

ASR will not backup data files. That should be backed up separately.

Create an ASR set

  • Start the Backup Utility by clicking Start->Run and type ntbackup
  • The Backup or Restore Wizard starts by default, we will not use this(though we could) , so click the Advanced mode link
  • On the Welcome tab, click Automated System Recovery Wizard
  • The wizard is pretty self-explained so follow it

Recover using ASR

  • Boot from the Windows Server 2003 CD and start the installation.
  • If you have a mass storage controller and must install drivers for it, do that by pressing F6 when prompted
  • Press F2 when prompted. You will be prompted to insert the ASR floppy, do that.
  • Follow the wizard
  • You will reboot and if you pressed F6 previously, do that again when prompted
  • Follow the wizard

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