Subject | RE: [firebird-support] Data on a mapped drive |
---|---|
Author | Steffen Heil |
Post date | 2004-06-15T13:12:24Z |
Hi
procedures, and therefore do not have to write another backup procedure.
Obviously they don't know, that backing up a gdb-file with
file-backup-software DOES NOT result in consistent and usable database
backups, right?
Any backup not made by gbak [and not testet by restoring to a test location]
is unreliable.
Databases in general are very vulnerable to data write order. Data must be
stored on the hard drive in the right order. If data is written in the wrong
order, this gives inconsistent databases. BTW, this is one of the reasons
not to allow network shares - one cannot control the caching algorithms used
on a network share. Backup suffer from this, because when they read the
database (to store it), they read it sequentially. That means, that newer
changes to the head of the file will not be backed up before newer changes
to the tail of the file. This also results in inconsistent - and therefor
useless - database files.
Regards,
Steffen
> That is true, which is how the system is working currently, but they wantthe data on the other server so it is archived with their current backup
procedures, and therefore do not have to write another backup procedure.
Obviously they don't know, that backing up a gdb-file with
file-backup-software DOES NOT result in consistent and usable database
backups, right?
Any backup not made by gbak [and not testet by restoring to a test location]
is unreliable.
Databases in general are very vulnerable to data write order. Data must be
stored on the hard drive in the right order. If data is written in the wrong
order, this gives inconsistent databases. BTW, this is one of the reasons
not to allow network shares - one cannot control the caching algorithms used
on a network share. Backup suffer from this, because when they read the
database (to store it), they read it sequentially. That means, that newer
changes to the head of the file will not be backed up before newer changes
to the tail of the file. This also results in inconsistent - and therefor
useless - database files.
Regards,
Steffen