Обсуждение: [REPOST] Remote database questions (NFS shared access, RServ)
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello: Reposting this due to no responses. Does anybody have any experience with these issues? ;-( I am constructing a billing system using PostgreSQL, ODBC, and C++. I have a primary database set up on a beefy server which is fed 24/7 by a transaction feeder, and is also used for processing the billing. I have a 2nd server which is being used as a hot backup server, which is also being fed by the transaction feeder. However, billing processing does not run through the feeder, so I find myself doing a daily dump on the appropriate tables on the production server, deleting the old data from the backup, and importing with copy from. Needless to say, RServ would be a better solution for this. I'm not sure how I would set up RServ to access a remote database, however. Is this possible? Also, I would like to provide the ability for users to look up their billing data via a CGI interface, which would perform queries to yet another server, to be set up for R/O access only (for performance, and security). I was thinking of using RServ for this purpose as well, but an even better solution seems to be to run my production (or backup mirror) from a NetApp over Gb NFS so there's no issues with replication. Is it possible, safe, and advisable to share a PostgreSQL database file via NFS, as long as non-masters are only accessing it R/O? Thank you in advance for your advice. - ---------------< LINUX: The choice of a GNU generation. >------------- Steve Frampton <frampton@LinuxNinja.com> http://www.LinuxNinja.com GNU Privacy Guard ID: D055EBC5 (see http://www.gnupg.org for details) GNU-PG Fingerprint: EEFB F03D 29B6 07E8 AF73 EF6A 9A72 F1F5 D055 EBC5 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.0 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE7wq7cmnLx9dBV68URAruLAKCJdhc7l1E9Tphha/5fxWZp0QDyfwCgiugt mg5KBHCdrqEyT+MY14it1fU= =YWmp -----END PGP SIGNATURE-----
Steve Frampton <frampton@LinuxNinja.com> writes:
> even better solution seems to be to run my production (or backup mirror)
> from a NetApp over Gb NFS so there's no issues with replication. Is it
> possible, safe, and advisable to share a PostgreSQL database file via NFS,
> as long as non-masters are only accessing it R/O?
No. (a) there is no such thing as R/O access in Postgres; (b) the
non-masters would have no guarantee of seeing a consistent view,
due to buffering inside the master.
I don't even recommend mounting a database over NFS, let alone trying
to share it. Too much risk of database corruption after a system crash,
because NFS provides only weak guarantees about write synchronization.
See the mailing list archives for past discussion about NFS risks.
regards, tom lane
Sharing a DB via NFS - No - absolutely not a good idea, no matter which DB you're talking about. However, you can remote access the DB through TCP/IP sockets, the Postmaster can be configured to listen to some port (5432 is the default) and you can have remote sessions running. To R/O access a PostGreSQL DB, you can grant 'select' rights to the remote users. It's not the same as opening the DB via a local postmaster process on a remote drive though - refer to my first point ;). Best regards, Chris ----- Original Message ----- From: "Tom Lane" <tgl@sss.pgh.pa.us> To: "Steve Frampton" <frampton@linuxninja.com> Cc: <pgsql-admin@postgresql.org> Sent: Tuesday, October 09, 2001 8:32 AM Subject: Re: [ADMIN] [REPOST] Remote database questions (NFS shared access, RServ) > Steve Frampton <frampton@LinuxNinja.com> writes: > > even better solution seems to be to run my production (or backup mirror) > > from a NetApp over Gb NFS so there's no issues with replication. Is it > > possible, safe, and advisable to share a PostgreSQL database file via NFS, > > as long as non-masters are only accessing it R/O? > > No. (a) there is no such thing as R/O access in Postgres; (b) the > non-masters would have no guarantee of seeing a consistent view, > due to buffering inside the master. > > I don't even recommend mounting a database over NFS, let alone trying > to share it. Too much risk of database corruption after a system crash, > because NFS provides only weak guarantees about write synchronization. > See the mailing list archives for past discussion about NFS risks. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com