differential backup 2005 advice

Morning.
Im running a FULL BACKUP in overwrite mode daily at 3am.
Im running a DIFFERENTAL BACKUP in overwrite mode hourly.
I cannot lose more than an hours data.
SQL 2005 Standard.
Backup Timeline:
3am Full
4am Differential
5am Overwrites 4am Differental.
etc ..
So if i restore the 5am Differential have i lost the 3am to 4am data ? (does
it let me do this ?)
If this is the case should I create a Differential overwrite as a separeate
file every hour ? (cannot append as data too large).
Example Timeline:
3am full
4am Differental4am.bak
5am Differental5am.bak
So i need to restore to 5am i need to
1. restore 3am full
2. restore Differential4am.bak
3. restore Differantal5am.bak
Is this correct ?
Thanks for any advice
Scottdifferential backup backups all changes since last full backup,
therefore in your scenario you don't lose any data.
If you would restore the database, the procedure is:
1- backup the tail of the log (if it's not corrupted)
2- rstore full
3- restore last diff
4- restore backuped log (from 1)
please read more in BOL
it wouldn't hurt to move/rename old diff when doing new one - instead of
overwrite. Consider the case when diff backup doesn't finish OK. then
you don't have any diff backup 'cause:
1- old file was overwritten
2- new one wasn't finished
Scott wrote:
> Morning.
> Im running a FULL BACKUP in overwrite mode daily at 3am.
> Im running a DIFFERENTAL BACKUP in overwrite mode hourly.
> I cannot lose more than an hours data.
> SQL 2005 Standard.
>
> Backup Timeline:
> 3am Full
> 4am Differential
> 5am Overwrites 4am Differental.
> etc ..
> So if i restore the 5am Differential have i lost the 3am to 4am data ? (does
> it let me do this ?)
> If this is the case should I create a Differential overwrite as a separeate
> file every hour ? (cannot append as data too large).
> Example Timeline:
> 3am full
> 4am Differental4am.bak
> 5am Differental5am.bak
> So i need to restore to 5am i need to
> 1. restore 3am full
> 2. restore Differential4am.bak
> 3. restore Differantal5am.bak
> Is this correct ?
> Thanks for any advice
> Scott
>|||Scott
BOL says
"A differential database backup records only the data that has changed since
the last database backup. You can make more frequent backups because
differential database backups are smaller and faster than database backups.
Making frequent backups decreases your risk of losing data."
Test your DDR
create database test
GO
create table test..test(id int identity)
insert test..test default values
backup database test to disk = 'c:\db.bak' WITH INIT
insert test..test default values
backup database test to disk = 'c:\db_diff1.bak' WITH DIFFERENTIAL
insert test..test default values
backup database test to disk = 'c:\db_diff2.bak' WITH DIFFERENTIAL
GO
RESTORE DATABASE test FROM disk = 'C:\db.bak' WITH FILE = 1, norecovery
--RESTORE DATABASE test FROM disk = 'c:\db_diff1.bak' WITH FILE = 1,
recovery
RESTORE DATABASE test FROM disk = 'c:\db_diff2.bak' WITH FILE = 1, recovery
select * from test..test
DROP Database test
"Scott" <scott_lotus@.yahoo.co.uk> wrote in message
news:extosaChIHA.748@.TK2MSFTNGP04.phx.gbl...
> Morning.
> Im running a FULL BACKUP in overwrite mode daily at 3am.
> Im running a DIFFERENTAL BACKUP in overwrite mode hourly.
> I cannot lose more than an hours data.
> SQL 2005 Standard.
>
> Backup Timeline:
> 3am Full
> 4am Differential
> 5am Overwrites 4am Differental.
> etc ..
> So if i restore the 5am Differential have i lost the 3am to 4am data ?
> (does it let me do this ?)
> If this is the case should I create a Differential overwrite as a
> separeate file every hour ? (cannot append as data too large).
> Example Timeline:
> 3am full
> 4am Differental4am.bak
> 5am Differental5am.bak
> So i need to restore to 5am i need to
> 1. restore 3am full
> 2. restore Differential4am.bak
> 3. restore Differantal5am.bak
> Is this correct ?
> Thanks for any advice
> Scott
>|||ah i see ! : )
many thanks for the reply and the rename tip.
so thats the key, differential is changes since last full ... didnt know
that. All makes sense now.
Whats "BOL" ?
all the best
scott|||Scott wrote:
> ah i see ! : )
> many thanks for the reply and the rename tip.
> so thats the key, differential is changes since last full ... didnt know
> that. All makes sense now.
> Whats "BOL" ?
> all the best
> scott
>
>
BOL is Books On Line - Microsoft SQL Server Help, available with F1 key
(no wonder) :-)|||Hi,
A DIFF backup contains all changes since the last FULL backup, so you
won't loose anything by skipping a DIFF backup file. Actually, in a
restore scenario, you will restore the latest FULL backup and the latest
DIFF backup - you don't need the DIFF backups in between.
Personally I prefer to backup up to seperate files rather than
overwriting existing files. By backing up to seperate files, I'll always
have the older files available if one of the files suddenly becomes
corrupt. If you keep overwriting and only have one file, then you've
lost everything if this file is damaged.
I know there might be cases where you can get older files from a
filebackup, but most companies only run file backups nightly. This means
that if the file is being corrupted in evening, then you've lost the
whole days backup.
You might also want to read up on BACKUP/RESTORE in BOL - that will
explain the different options you have.
Regards
Steen Schlüter Persson
CRM System Specialist / DBA
Scott wrote:
> Morning.
> Im running a FULL BACKUP in overwrite mode daily at 3am.
> Im running a DIFFERENTAL BACKUP in overwrite mode hourly.
> I cannot lose more than an hours data.
> SQL 2005 Standard.
>
> Backup Timeline:
> 3am Full
> 4am Differential
> 5am Overwrites 4am Differental.
> etc ..
> So if i restore the 5am Differential have i lost the 3am to 4am data ? (does
> it let me do this ?)
> If this is the case should I create a Differential overwrite as a separeate
> file every hour ? (cannot append as data too large).
> Example Timeline:
> 3am full
> 4am Differental4am.bak
> 5am Differental5am.bak
> So i need to restore to 5am i need to
> 1. restore 3am full
> 2. restore Differential4am.bak
> 3. restore Differantal5am.bak
> Is this correct ?
> Thanks for any advice
> Scott
>|||: ) brillant , thank you very much everyone.
Scott|||I just thought that you might be interested in a stored procedure for doing
backups that supports creation of backup files with date and time in the file
name, verification of backups as well as deletion of old backup files. It is
available on http://ola.hallengren.com.
Ola Hallengren
"Scott" wrote:
> : ) brillant , thank you very much everyone.
> Scott
>
>