I work with a team that configures and supports OSF/1 systems...
Unfortunately, although we have to set up and maintain these systems,
we do not specify them, so we end up dealing with systems that are
sometimes underconfigured for memory, and sometimes underconfigured for
disk (swap) space.
I'm trying to come up with an algorithm to
apply to all cases (for others to follow) which can be used to pre-determine:
1) how much swap to configure
2) whether to use lazy or eager swap allocation mode.
(default is to use eager swap mode, if possible.)
In general we do have a vague predicted idea, based on user license,
of the average amount of virtual memory required on the system. However,
if the license is increased in the future, of course this would increase.
This is what I have come up with - Comments??
Given that system has some amt_of_real_mem, and some ave_memory_required.
1) if amt_of_real_mem > ave_mem_req
then
if there is (2 * ave_mem_req ) swap avail on system
allocate that amount of swap and leave swap mode eager.
2) if amt_of_real_mem > ave_mem_req
then
if there is not at least ( 2 * ave_mem_req ) swap avail
allocate max avail swap and change swap mode to lazy.
3) if amt_of_real mem < ave_mem_req
then
if there is at least (2 * ave_mem_req ) swap available
allocate that amountof swap and leave swap mode eager.
4) if amt_of_real_mem < ave_mem_req
then
if theres is not at least (2 * ave_mem_req ) swap avail
allocate max avail swap and change swap mode to lazy
and PRAY!
Notes:
A. always allocate at least amt_of_real_mem of swap ESPECIALLY if
using eager swap mode.
B. in case 1) if disk space is plentiful go ahead and allocate
up to 2 * amt_of_real_mem in swap. In case 3) allocate up to
3 * amt_of_real mem if plentiful.
Suggestions? comments on defaulting to eager swap mode...
Thanks,
Shanna Leonard
Unix Systems Group
Sunquest Information Systems
ssl_at_alpha.sunquest.com
Received on Wed Aug 30 1995 - 04:15:19 NZST