I have two more questions :
1 - in case server has been shutdown abruptly, db.lck
and dbex.lck files are still present in <dbdir>.
Later on, if derby server is only started but no client ever
connects to this database, these files remain there, unchanged.
Thus, even after derby server has been properly shutdown,
db.lck files are to be expected : in this case, this does not
indicate that <dbdir> is unsuitable for copy.
2 - OK, I'll try to connect to server port to see if it succeeds
or not. However, is it correct to assume that
"1527 port no more bound" implies "all <dbdir> are safe for
In case derby server first closes its server socket, _then_ closes
properly all the opened databases, this assumption may be false.
(I haven't looked into derby server code yet ; I have observed
that server shutdown may require several seconds, depending on
file system type, machine load...)
So in conclusion, it is still quite hard to figure out _when_ it is
to backup a <dbdir>. Am I wrong ?
Anyway I'll try to deal with all these informations.
Thank you for your help.
Le 21/09/2012 22:23, Dag Wanvik a écrit :
On 21.09.2012 18:54, Mo Maison wrote:
Thank you for this tip.
I do not feel confident with whole DB freeze, as I do not know
thus I can't estimate the time required to copy files. Also I
goes wrong and UNFREEZE is never called.
In case, is restarting the Derby server sufficient to "forget"
this frozen state ?
Regarding my initial question : is there somewhere a file to
that indicates that server is fully shutdown ?
There is probably a kind of lock file that indicates that a DB
is being used ?
<dbdir>/db.lock is created when a database is booted by a
VM, to avoid several VMs trying to boot the same database.
The derby *server* (engine) can open several databases. By by
shutting down a database
the corresponding lock file is removed, but the server can still
be alive waiting for connections. Presently, I think the only way
check if the server is still alive is to try to connect to its
Watching server process in /proc would be ugly and not portable.
Le 31/07/2012 22:59, José Ventura a écrit :
I'm using the tips in this page to achieve a similar
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
On Tue, Jul 31, 2012 at 5:49 PM, Mo
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
However, I have observed that, on a slow filesystem, somes
files get deleted while tar is reading them. Which let me
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
the cold backup ?
I use Derby 10.6.2 on 32 bits Linux.
Thank you for your advices,