If your memory reservations exceed your backing store, the additional reservations are being made against physical RAM. That means you have physical memory that is not available for active use, either for memory allocations or for things like file system buffering. I hesitate to say that it makes you more likely to see memory allocation failures, but it does mean that if you request enough memory you may see the requests fail even though you have physical memory that is not actively in use. That isn't a desirable situation and means that you are potentially "wasting" RAM.
If you find that your memory reservations exceed your currently defined backing store, you should try to either reduce the total reservations or add additional backing store. So yes, adding more swap space is one way to deal with the issue. You can either increase the size of your swap device by repartitioning, or add additional swap devices. HTH, David ----- Original Message ----- From: Awais Vaseer <[EMAIL PROTECTED]> Date: Monday, June 16, 2008 7:27 pm > Hi David, > > Thanks for the detailed reply. You said: "If your memory reservations > exceed the size of your backing store, you can have memory allocation > failures while still having lots of unallocated backing store." > > In our case the swap device is 40GB in size. Does it mean we're likely > to see memory allocation failures if 'swap -s' reports more than 40GB > as 'reserved' ? Would allocating extra swap space help under these > circumstances ? > > Thanks & Regards, > > Awais > > _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
