May 15, 2003 at 8:19 am
I am in the process of redesigning our current backup strategy. Currently, our strategy calls for hourly full backups to tape using arc serve. The problem is with the potential hardware failure of the drives, cost of tapes, and lifespan of tape. My new strategy would incorporate one full backup to Disc and diff thoughout the day. I would like to know how common is it for .bak files to become corrupt? What happens to DIFF's if the previous FULL backup becomes corrupt? Can I use a FULL backup from an earlier point in time?
Any input what be appreciated. Thank you
May 15, 2003 at 8:30 am
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how common is it for .bak files to become corrupt?
Neve exeperience once.
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What happens to DIFF's if the previous FULL backup becomes corrupt?
If previous full backup corrupt, your DIFF will be useless.
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Can I use a FULL backup from an earlier point in time?
Do you mean use DIFF with Full backup early than privious full backup? You can't.
The backup strategy should include transaction log backup.
May 15, 2003 at 8:44 am
My goal is to reduce potential data loss to 1 hour. I originally planned to run 2 FULL backups a day followed by Differentials every hour. With this strategy I could potentially loose 11 hours worth of data if a FULL backup becomes corrupt. Any suggestions on how I can overcome this? What if I perform X-Log backups every 15min? Can I use X-Log backups to brigde the gap between the LAST KNOW GOOD FULL backup and DIFF and the moment of Data loss?
EX:
12am FULL - file is good
DIFF every hour until 12pm
X-Log backups every 15minutes
12PM FULL - file is corrupt
Diff every hour until 12am
X-Log every 15 minutes
I need to recover data up to 8pm. If my 12pm Full is corrupt, my diffs following are useless, Correct? So, I would need to restore from the 12am FULL and 11am DIFF, Correct? Now, Can i use the X-Log backups to recover the data loss due to corrupted 12pm FULL and diffs rendered useless?
May 15, 2003 at 9:03 am
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With this strategy I could potentially loose 11 hours worth of data if a FULL backup becomes corrupt. Any suggestions on how I can overcome this? What if I perform X-Log backups every 15min? Can I use X-Log backups to brigde the gap between the LAST KNOW GOOD FULL backup and DIFF and the moment of Data loss?
That is exactly why you need transaction log backups. As long as you have transaction log backups, you will be able to recover your database up to the point of time your database failure. In your example.
1. Restore 12am FULL backup.
2. Restore last diff backup before 12PM FULL backup which is corrupt.
3. Restore transaction log backup from last diff backup untill the transaction log backups have bridged 12PM FULL backup.
4. Restore latest diff backup.
5. Restore the rest of transaction log backups.
May 15, 2003 at 9:26 am
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3. Restore transaction log backup from last diff backup untill the transaction log backups have bridged 12PM FULL backup.4. Restore latest diff backup.
5. Restore the rest of transaction log backups.
So if I use X-log to fill in the hole left by the corrupt FULL, I can then use the DIFFs?
May 15, 2003 at 9:39 am
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So if I use X-log to fill in the hole left by the corrupt FULL, I can then use the DIFFs?
Yes, you can. Do test your plan before implement it to your production servers.
Edited by - Allen_Cui on 05/15/2003 09:39:56 AM
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