There is also the question of hardware. Are the +RECO and +DATA disk
groups comprised of different physical devices on different controllers
or did you just ask your storage admin for some SAN storage and created
disk groups from that? If the same physical disks are used for both disk
groups, the logical separation will not help you much. Problem with the
traditional SAN is that it obscures the connection between the actual
physical disks and LUN devices. Actually, SAN is like a box of
chocolate, you never know what you'll get.
Of course, the new generation of SSD SAN devices like XTremIO or Pure
deals with that by having much faster disks with much greater
throughput. As for the shared memory error, set the shared_pool_size in
the spfile and Oracle will not go below that. Figure out how much do you
need to keep everything what you need in the shared pool and set the
parameter in spfile.
On 5/5/21 7:47 AM, Pap wrote:
We have recently created a new UNDO tablespace on RECO tablespace because of space crunch on DATA disk group. So basically all the DML and everything happens on DATA whereas UNDO sits on RECO, so can it be the cause of such issues anyway?
