Login or Register to Ask a Question and Join Our Community


Solaris

Coredumps and swap - was part of Solaris Mem Consumption

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Operating Systems Solaris Coredumps and swap - was part of Solaris Mem Consumption
# 8  
Old 08-08-2008
incredible - of course your dump could be rather large but i run m9000's and have never seen a core file greater then a few gigs tops. we are talking about 1-4 TBs of memory and 64 sparc64 VI (128 cores) processors.
# 9  
Old 08-09-2008
For your info M series is a collaboration of Fujitsu with SUN and their architectures do differ.. Though you may find M9000 is working like a 6900 system.. Smilie
If its gonna be a "SUN" mid-range or highend servers, what I say still makes sense.
# 10  
Old 08-09-2008
Quote:
Originally Posted by Annihilannic
That is a very old rule of thumb which I no longer agree with. Memory is so cheap and plentiful these days that you should hardly ever require swap, if you do it is a sign of problems. I generally don't ever configure more than 4GB of swap, even on a 64+GB system.
Yes, I agree with this. The old 2 pounds of swap for every pound of memory was back in the old days when memory was expensive and it was cheaper to use disk swap.

If you have 7 GB of RAM, something is really wrong if you need 14GB of swap.

4GB of swap is more than enough, good post Annihilannic. Thanks.
# 11  
Old 08-09-2008
There is a lot of infomation in this thread which is not valid. Almost everything Incredible has stated in this thread is incorrect in terms both of system configurations and reasons for choosing swap size.

A few points worth note.
  1. You don't need to allocate any swap space to deal with savecores, and have not since Sorlais 8.
  2. Solaris will never go into a panic-reboot cycle as a result of not having savecore space. It will simply not save a core dump if it has no space.
  3. Twice memory as swap is no longer a good choice unless you really can't afford to upgrade.
  4. If you have a lot of pagout you do not have enough memory, it's as simple as that.
  5. You do not need minimum 16GB swap for 64 or 128GB of memory, but you may need to have more swap if you have applications using ISM (Intimate shared memory) or DISM (Dynamic Intimate Shared Memory) such as Sybase or Oracle databases.
  6. There is no reason to treat an M-Series differently from any other Solaris box.

In summary you can get by to some extent if you don't have enough memory by adding swap, but it will hurt performance. Ideally you should have enough memory to run all your applications in memory, and the general rule of thumb nowadays is about 30% of memory for swap but there are more detailed reccomendations in the Solaris documentation.

Jim Laurent at Sun wrote a blog on this topic about a year ago, which you could look up.

EDIT: Found the blog:Solaris FAQ: Myths and facts about Solaris swap space : Jim Laurent's Weblog
# 12  
Old 08-09-2008
Quote:
Originally Posted by reborg
There is a lot of infomation in this thread which is not valid. Almost everything Incredible has stated in this thread is incorrect in terms both of system configurations and reasons for choosing swap size.

A few points worth note.
  1. You don't need to allocate any swap space to deal with savecores, and have not since Sorlais 8.
  2. Solaris will never go into a panic-reboot cycle as a result of not having savecore space. It will simply not save a core dump if it has no space.
  3. Twice memory as swap is no longer a good choice unless you really can't afford to upgrade.
  4. If you have a lot of pagout you do not have enough memory, it's as simple as that.
  5. You do not need minimum 16GB swap for 64 or 128GB of memory, but you may need to have more swap if you have applications using ISM (Intimate shared memory) or DISM (Dynamic Intimate Shared Memory) such as Sybase or Oracle databases.
  6. There is no reason to treat an M-Series differently from any other Solaris box.

In summary you can get by to some extent if you don't have enough memory by adding swap, but it will hurt performance. Ideally you should have enough memory to run all your applications in memory, and the general rule of thumb nowadays is about 30% of memory for swap but there are more detailed reccomendations in the Solaris documentation.

Jim Laurent at Sun wrote a blog on this topic about a year ago, which you could look up.

EDIT: Found the blog:Solaris FAQ: Myths and facts about Solaris swap space : Jim Laurent's Weblog
Excellent followup reborg. Thanks for taking the time to set the record straight.
# 13  
Old 08-10-2008
Quote:
Originally Posted by reborg
[*]You don't need to allocate any swap space to deal with savecores, and have not since Solaris 8.
I'm afraid this statement is misleading.
Solaris still requires a single dump slice large enough for kernel crash dump data to be recorded, and there is no much point not using a swap area for it.
Even while this data is compressed since Solaris 8, I wouldn't recommend to use less than the RAM size as swap size as it is the only way to guarantee a crash dump will fit.
# 14  
Old 08-10-2008
Quote:
Originally Posted by jlliagre
I'm afraid this statement is misleading.
Solaris still requires a single dump slice large enough for kernel crash dump data to be recorded, and there is no much point not using a swap area for it.
Even while this data is compressed since Solaris 8, I wouldn't recommend to use less than the RAM size as swap size as it is the only way to guarantee a crash dump will fit.
Most folks seem to say that 4GB is large enough for any Solaris core dump. In addition, you can specify to limit the size of the core dump.

Since I use Linux, I don't recall ever needing a core dump, and normally I find them a waste of disk space on most systems. Better to have a kernel that does not dump cores .... Smilie that you have massive core dumps.

In other words, I don't think that core dumps should be must of a factor in thinking about swap.
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Solaris

Solaris 10 swap device and filesystem

Hi all, Q1) Due to application requirement, i am required to have more swap space. Currently my swap is on a partition with 32GB. I have another partition with 100GB, but it already has a UFS filesystem on it. Can i just swap -d /dev/dsk/current32gb and swap -a /dev/dsk/ufs100gb ? Will... (17 Replies)
Discussion started by: javanoob
17 Replies

2. Solaris

Swap Solaris 5.10

I have a customers that is getting grid alerts that swap is over 95% utilized. When I do swap -l on the machine I get the following results. $ swap -l swapfile dev swaplo blocks free /swap/swapfile - 16 6291440 6291440 /swap/swapfile2 - 16 8191984... (18 Replies)
Discussion started by: Michael.McGraw
18 Replies

3. Solaris

Problem with Swap consumption

Hi Experts, I have M4000 server with 132 GB Physical memory. 4 sparse zones are running under this server, which are running multiple applications. I am not getting any pointer, where swap space is getting consumed. Almost 97% of swap space is being used. I checked all /tmp (of zones as well),... (7 Replies)
Discussion started by: solaris_1977
7 Replies

4. Solaris

How to check power consumption of Solaris servers ?

hi friends, we are relocating our DC and need to plan out electrical power for the new DC. are there ways i could find the actual power consumption from my current servers ? instead of the product specs. (2 Replies)
Discussion started by: Exposure
2 Replies

5. Shell Programming and Scripting

Determining User Consumption in solaris

Inorder to find the user memory consumption I used the command: prstat -s cpu -a -n 10 But now I want to automate it and want to write the output to a file. How can I write the out put of user name and percentage of consumption alone to an output file.? (2 Replies)
Discussion started by: engineer
2 Replies

6. Solaris

Solaris 10 SWAP SPACE

We have a SPARC system which is running on Solaris-9 and Physical memory size is 16GB.We have allocated 32GB SWAP space(2 times of physical memory).But when we use df -h command it shows following output and SWAP space size shows more than our allocated space # df -h Filesystem size used... (2 Replies)
Discussion started by: cyberdemon
2 Replies

7. Solaris

Solaris 10 - Memory / Swap

Hi all Got myself in a pickle here, chasing my own tail and am confused. Im trying to work out memory / swap on my solaris 10 server, that Im using zones on. Server A has 32Gb of raw memory, ZFS across the root /mirror drives. # prtdiag -v | grep mem = Memory size: 32768 Megabytes #... (1 Reply)
Discussion started by: sbk1972
1 Replies

8. AIX

Zerofault terminates and coredumps - Segmentation fault

Hi, I am using zerofault in AIX to find memory leaks for my server. zf -c <forked-server> zf -l 30 <server> <arguments> Then after some (5 mins ) it terminates core dumping and saying server exited abnormally. I could not understand the core file generated: its something like show in below... (0 Replies)
Discussion started by: vivek.gkp
0 Replies

9. Solaris

Solaris Mem Consumption

We have Sun OS running on spark : SunOS ciniwnpr67 5.10 Generic_118833-24 sun4u sparc SUNW,Sun-Fire-V440 Having Physical RAM : Sol10box # prtconf | grep Mem Memory size: 8192 Megabytes My Top Output is : 130 processes: 129 sleeping, 1 on cpu CPU states: 98.8% idle, 0.2% user, 1.0%... (27 Replies)
Discussion started by: rajwinder
27 Replies

10. Programming

Reg: char ptr - Coredumps

#include <stdio.h> void main() { int Index=1; char *Type=NULL; Type = (char *)Index; printf("%s",Type); } Getting coredump (5 Replies)
Discussion started by: vijaysabari
5 Replies
Login or Register to Ask a Question