Re: ontape/ondatartr restores

---------- > From: ntruby@netcomuk.co.uk > To: informix-list@rmy.emory.edu > Subject: ontape/ondatartr restores > Date: vrijdag 1 november 1996 19:49 > > It's well known that OnLine demands that a restore requires the original > chunks to be available, or at least the same symbolic links. > > But why is this? I can't understand why, since the physical location of > pages is unimportant. The important thing is the relative address of > each page wrt the start of its dbspace. > > Other DBMSs, e.g. Adabas, work entirely on relative address blocks > (pages). This makes transfer of data between servers, or between prod > and dev on the same server, much easier. > > Neil Truby > Chase Manhattan Bank > Bournemouth, UK Neil, There are three things which are required to be the same when you restore an archive. These shared memory parameters must not be smaller - (USERTHREADS, BUFFERS, LOCKS, TBLSPACES) Mirroring parameters (MIRRORPATH, MIRROROFFSET) should be the same. Same device names must be available. The exact same device does not need to be available, the only requirements are that the device name must be the same (use symbolic links if not), and the chunk must be at least the same size as the archived chunk. This is because the ROOTPATH and ROOTOFFSET onconfig parameters are stored in the archive so ondatartr or ontape uses these device names to restore the rootdbs. For this reason, it is a good idea to use links when you first initialise the engine for example: /dev/chunk1 -> /dev/rdsk/dks0d1s0 /dev/chunk2 -> /dev/rdsk/dks0d2s0 So when you restore you can use a different device just be changing the link. Scott. Scott Hanson Junior Consultant tel.: (31) 10 207 5400 scott@worldaccess.nl Database & O/S Technology fax.: (31) 10 456 9122 http://www.worldaccess.nl/~scott NexTime B.V.