First off: SAP has a long history of "recommending" certain amounts of swap. You can safely ignore these recommendations as they are complete nonsense.
If your system has some memory shortage it will start swapping. Once it does so you need the swap space and once this swap space it exhausted (or nearly exhausted) your system will start killing processes - so far, so common. But long before your swap space is exhausted you will have a severe performance degradation and you customers will be all over you to get the system back to speed - so far, so common either.
But as long as your system doesn't have a memory shortage you don't need swap space - *any* swap space! This means, while it is a god idea to have some swap space as a contingency you don't *need* it (under "normal" circumstances, which means there is indeed enough memory) at all.
SAP now recommends to configure swap space based on a simple formula: your current amount of memory times some factor (if i remember correctly it was 2). Would you increase your memory, which would make swapping even less probable their recommended amount would even increase, while there is a simple way to meet their requirements: reduce the memory of the system, which will make swapping occur more often, but SAP will recommend a smaller swap space for this (in fact now ill-tuned) system!
You see, their recommendation is simply bovine manure.
Historically the AIX kernel used an "early swap allocation" and allocated swap space for every started program, so the recommendation of SAP made - least some - sense back then. Since the days of AIX 5 (or was it with 5.1? A lot of years back for sure!) IBM changed that and now AIX uses late swap allocation. Since this change the recommendation makes no sense at all.
Regarding your error message: There is a parameter for each LV, which shows the maximum numbers of LPs that can be assigned to it. The command xoops told you will increase this maximum for the LV which holds your swap space. You can also do it using SMIT by issuing
Code:
smitty chlv
and follow the menus on screen.
I hope this helps.
bakunin
Moderator's Comments:
BTW.: i have changed the threads title to "recommended".
Hy all,
i've a little problem with the size of the swap. I've an old solaris machine, with 4Go, and swap is taking 500Mo for only 1% used at any time.
So : how can i change this size without problems ?????
(ok it may be a stupid question, but it's a real problem when you lose about 1 or 2... (3 Replies)
Hello all,
I just got a laptop with redhat linux 7.2 installed, but during the installation the installer only put 1gig of sawp space( this laptop has 1gig of RAM). To my understanding when creating swap space, the size is determine by double the RAM. Therefore my question is that how do I... (2 Replies)
I have a machine: SunOS <server> 5.9 Generic_117171-15 sun4u sparc SUNW,Sun-Fire-480R
It has these filesystems:
Filesystem size used avail capacity Mounted on
/dev/md/dsk/d0 19G 15G 3.9G 80% /
/proc 0K 0K 0K 0% /proc... (6 Replies)
few questions
a. where can I find the RAM of a server? im about to install redhat on a server (reformat). need to know because it will be my basis for swap size. i saw something line 3048MB detected upon boot. is this the memory?
b. what is the command in lunux to check the original size of... (2 Replies)
Dear All,
How to increase the swap size when physicall memory reaches 60 %. OR it can be only done after the physicall memory is full.
Rgds
Rj (8 Replies)
Hi All,
I want to know how to understand the actual swap size.
My o/p shows as below
root@ecovs1a # swap -s
total: 4546056k bytes allocated + 358856k reserved = 4904912k used, 5046688k available
root@ecovs1a # swap -l
swapfile dev swaplo blocks free
/dev/md/dsk/d31 ... (9 Replies)
Hi Experts,
Need your advise in determining the size of swap space in of the new HP-Ux server.
Server is having 32G of physical memory.
Ideally what amout of physical memory should be allocated as a swap space?
Following document from HP suggests to have minimum swap space... (2 Replies)
Hi,
the /tmp size is less whereas the size allocated to swap is quite big. how to increase the size of /tmp -
#: swap -l
swapfile dev swaplo blocks free
/dev/md/dsk/d20 85,20 8 273096 273096
#: swap -s
total: 46875128k bytes allocated + 2347188k reserved =... (2 Replies)
Discussion started by: psb74
2 Replies
LEARN ABOUT SUNOS
wscasecmp
wstring(3C) Standard C Library Functions wstring(3C)NAME
wstring, wscasecmp, wsncasecmp, wsdup, wscol - Process Code string operations
SYNOPSIS
#include <widec.h>
int wscasecmp(const wchar_t *s1, const wchar_t *s2);
int wsncasecmp(const wchar_t *s1, const wchar_t *s2, int n);
wchar_t *wsdup(const wchar_t *s);
int wscol(const wchar_t *s);
DESCRIPTION
These functions operate on Process Code strings terminated by wchar_t null characters. During appending or copying, these routines do not
check for an overflow condition of the receiving string. In the following, s, s1, and s2 point to Process Code strings terminated by a
wchar_t null.
wscasecmp(), wsncasecmp()
The wscasecmp() function compares its arguments, ignoring case, and returns an integer greater than, equal to, or less than 0, depending
upon whether s1 is lexicographically greater than, equal to, or less than s2. It makes the same comparison but compares at most n Process
Code characters. The four Extended Unix Code (EUC) codesets are ordered from lowest to highest as 0, 2, 3, 1 when characters from different
codesets are compared.
wsdup()
The wsdup() function returns a pointer to a new Process Code string, which is a duplicate of the string pointed to by s. The space for the
new string is obtained using malloc(3C). If the new string cannot be created, a null pointer is returned.
wscol()
The wscol() function returns the screen display width (in columns) of the Process Code string s.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO malloc(3C), string(3C), wcstring(3C), attributes(5)SunOS 5.10 29 Dec 1996 wstring(3C)
10-13-2011
