Thanks to:
Kjell Andresen <kjell.andresen_at_usit.uio.no>
"Robert L. McMillin" <rlm_at_syseca-us.com>
I did not get many answers...
And a "me too"
==========
Rule of thump:
-Swap space 2*RAM up to 3*RAM
-RAM at least 64MB (but depends on applications running...)
(I would like to get some more hints how to plan RAM requirements)
If you have enough RAM (whatever this means...) you can remove (rename)
/sbin/swapdefault. Then you don't need so much swap space.
Rainer Landes, eMail: Computer-Administration_at_Physik.uni-karlsruhe.de
Tel(+49)721 608 3578
http://www-comp.physik.uni-karlsruhe.de/
Computer facilities of the Faculty of Physics, Univ. of Karlsruhe, GER
============
Answers in detail:
-------
"Robert L. McMillin" <rlm_at_syseca-us.com>
Rule of thumb is 2:1 swap:RAM. I like 3:1, personally.
---------
Kjell Andresen <kjell.andresen_at_usit.uio.no>
> How do I plan RAM and Swap space on a workstation?
> (Rule of Thump?)
This is complicated matter as stated in the systems manual.
So I've done it like this on our alphas running DU:
They need to have at least 64 MB ram, the more the better!
They need 2,5 to 3 times this for swap.
If you buy addiotional memory make another swap partition at the same
factor and recompile the kernel.
This leave you with enough swapspace usualy. Use
# swapon -s
to monitor.
We recommend
# mv /sbin/swapdefault /sbin/swapdefault.moved to decrease the need for
swapspace.
The alphas are really memory consuming compared to other uni*ces.
Another approch is to set up as little swap as you dare, but then you need
more than _ENOGH_ memory!
==============
Original question:
------------
How do I plan RAM and Swap space on a workstation?
(Rule of Thump?)
--------
Most of the informations from swapon -s or vmstat or top
are concerning the very moment I issue the commands.
How do I get informations about the top / average usages?
Also, how do I interpret the information correctly?
How do I calculate the needed additional RAM so that paging is reduced to
an acceptable amount?
How do I calculate the really needed swapspace?
How are you planning this? Which information are you using?
How are you collecting this information?
============
some details, examples, background information:
============
After the upgrade to DU4.0b (with CDE surface) one of our workstations
(64MB RAM) seems to be much slower (swapping).
Also, swap space was too small, which I increased now.
This machine is used for interactive logins (X11) and some computing jobs
with nice 19.
At the moment I get
# vmstat 2 4
Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
4124 18 4427 167 2663 24M 1M 1M 2M 2M 88K 30 153 326 94 2 5
4124 18 4442 152 2663 154 12 120 31 8 0 4 30 347 96 4 0
4124 18 4442 152 2663 95 0 95 0 0 0 7 31 343 96 4 0
4124 18 4441 152 2664 95 0 95 0 0 0 6 24 344 96 4 0
swapon -s gives:
...
Total swap allocation:
Allocated space: 68786 pages (537MB)
Reserved space: 23145 pages ( 33%)
In-use space: 10005 pages ( 14%)
Available space: 45641 pages ( 66%)
On an other workstation (384MB RAM) which is mainly used for computing
(no monitor attached to it) I've got the feeling that there is not
all of the RAM really used.
vmstat 2 4 currently gives me
# vmstat 2 4
Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
5122 20 33K 7440 6658 20M 2M 8M 246K 3M 1306 24 310 324 90 1 9
5122 20 33K 7425 6658 159 3 133 0 6 0 8 3K 357 97 3 0
5122 20 33K 7425 6658 111 0 111 0 0 0 8 4K 266 97 3 0
5122 20 33K 7425 6658 111 0 111 0 0 0 4 3K 344 97 3 0
swapon -s gives:
...
Total swap allocation:
Allocated space: 212769 pages (1662MB)
Reserved space: 41433 pages ( 19%)
In-use space: 11211 pages ( 5%)
Available space: 171336 pages ( 80%)
Received on Tue Mar 11 1997 - 10:52:31 NZDT