6.28 (x86 Only) Many ISCSI or Fibre Channel LUNs Require More Server Memory

As the number of iSCSI or Fibre Channel LUNs or targets used by an Oracle VM Server is increased, the memory consumption increases on the server. This is normal, as more memory is required by dom0 to connect to each LUN or target. Therefore, if you intend to add a large number of LUNs to a server, you must allocate an appropriate amount of physical memory to the server to handle this, and the additional memory must be assigned to dom0 for use. Typically this should be around 1 MB per LUN on top of the memory allocated to run dom0. See Changing the Oracle VM Server (Dom0) Memory Size for information on how to change the dom0 memory allocation.

Memory is assigned to dom0 within the /boot/grub/grub.conf on the server, as shown in the following line of the configuration:

kernel /xen.gz console=com1,vga com1=38400,8n1 dom0_mem=1176M allowsuperpage

Ideally this should be allocated at installation so that the dom0 grub configuration is updated automatically. Otherwise, you may need to adjust the grub configuration yourself.

Insufficient memory to support the number of LUNs on an Oracle VM Server results in out-of-memory (oom) kills and server instability.

Bug 17614799