db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mo Maison <momai...@yahoo.fr>
Subject Re: Stopping network server & cold backup
Date Fri, 21 Sep 2012 16:54:07 GMT

Thank you for this tip.
I do not feel confident with whole DB freeze, as I do not know DB size,
thus I can't estimate the time required to copy files. Also I fear something
goes wrong and UNFREEZE is never called.
In case, is restarting the Derby server sufficient to "forget" this 
frozen state ?

Doc says that "Derby might block applications that attempt to write to
a frozen database" : is it possible to explain exactly under which 
circumstances
the writer would be blocked ?

Regarding my initial question : is there somewhere a file to watch
that indicates that server is fully shutdown ?
There is probably a kind of lock file that indicates that a DB is being 
used ?
Watching server process in /proc would be ugly and not portable.

M. Maison


Le 31/07/2012 22:59, José Ventura a écrit :
> I'm using the tips in this page to achieve a similar goal:
>
> http://db.apache.org/derby/docs/10.6/adminguide/cadminhubbkup75469.html
>
> Basically, instead of shutting down the server, you use a command to 
> freeze the DB, then copy the files, then unfreeze the DB. The freeze 
> call will block until it is safe to copy the files.
>
> On Tue, Jul 31, 2012 at 5:49 PM, Mo Maison <momaison@yahoo.fr 
> <mailto:momaison@yahoo.fr>> wrote:
>
>     Hello Derby users,
>
>     I encounter sometimes a problem during cold backups :
>     Derby is launched as a server (listening localhost only ) ;
>     I stop the network server with standard command :
>       java -cp ... \
>       org.apache.derby.drda.NetworkServerControl shutdown \
>       -h localhost -p 1527
>
>     Right after command has returned, I perform a tar of the
>     database files.
>     However, I have observed that, on a slow filesystem, somes
>     files get deleted while tar is reading them. Which let me think
>     that server is not fully stopped when process returns
>     (and thus backup may be corrupted).
>
>     Is that expected ?
>     How can I be sure that everything is quiescent before performing
>     the cold backup ?
>     I use Derby 10.6.2 on 32 bits Linux.
>
>     Thank you for your advices,
>
>      M. Maison
>
>


Mime
View raw message