db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Stanley Bradbury <Stan.Bradb...@gmail.com>
Subject Re: Client/server plus network storage of database files
Date Tue, 23 Sep 2008 17:56:18 GMT
Daniel Noll wrote:
> Stanley Bradbury wrote:
>> The problem is that I/O across a network cannot to be guaranteed.  
>> You are actually losing data buffered along the network when the 
>> network fails.  Derby detects this when is boots the next time and 
>> finds the checksums and timestamps on the files int the database are 
>> out of sync.
>> Derby database files must reside local to the machine hosting the 
>> Derby DBMS engine.
>
> So what does Derby define as "across a network"?  FireWire is 
> technically a network protocol after all.
>
> Does this just mean I/O across TCP/IP?  Or just I/O across SMB?  Or 
> across NFS and SMB?  Or generally any network protocol which happens 
> to buffer?  But directly connected disks also buffer, so presumably it 
> isn't that last option.
>
> Daniel
>
>
Not being a hardware or network guy I  can't speak in detail to all the 
TLAs you are using but do know the following is documented:  Derby 
database files must reside local to the machine hosting the Derby DBMS 
engine.  So that leaves out anything over TCP/IP and I know that NFS 
mounts, Windows file shares and Samba mounts.  These systems will result 
in corruptions because there is not way to insure that a physical write 
to disk was completed.  


Mime
View raw message