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Bob Zelin
sysctl.conf file ?
on Aug 28, 2013 at 2:04:00 am

Hi -
can someone tell me what this file, that is NOT executable in the /etc folder does for Assimilate Scratch ? Can I delete this (or replace it), or do I have to supplement this file if I want to make changes to it ?

Thank you -
Bob Zelin

Bob Zelin
Rescue 1, Inc.
maxavid@cfl.rr.com


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Matt Geier
Re: sysctl.conf file ?
on Aug 28, 2013 at 3:51:33 am

Bob,

How are you?

Just some help for you to set you down a path here....I know you'll figure out what you need after this...

This file is used a lot in FreeBSD...
for me... it screams Small Tree in certain ways....I know that file is used for certain networking configuration variables and other types of parameters to load a config, or get the O/S to turn certain behaviors on/off up/down etc...

You might check to see the contents of the file before you remove it... just in case there's something it's looking at... should be able to use emacs or vi to look at the contents....

I would also check to see if Small Tree is running anything on this solution - Cards, Storage, etc... --- That's just a thought ... I don't know for sure like you will.

From WikiPedia...in general about the file;
In BSD these parameters are generally objects in a management information base (MIB) that describe tunable limits such as the size of a shared memory segment, the number of threads the operating system will use as an NFS client, or the maximum number of processes on the system; or describe, enable or disable behaviors such as IP forwarding, security restrictions on the superuser (the "securelevel"), or debugging output. Source: http://en.wikipedia.org/wiki/Sysctl

I know you're the man! If you need more details on this, and what you might affect, I'm sure someone else here in this forum will post, assuming it's common, otherwise, shoot an email to Small Tree ---

Email me sometime... or send me a message on cow or something!!
(I've moved on from Small Tree since I talked to you last....)

Matt Geier
651-808-1338
(Creative Product Evangelist)
(Technical Sales Consultant)
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(Creative Design Workflow Consultant)
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Bob Zelin
Re: sysctl.conf file ?
on Aug 28, 2013 at 6:26:13 pm

Hi Matt -
this is used for tuning 10gig cards in the Mac but if this is done on a Scratch system, I don't want to delete anything. BUT this file doesn't work unless it is made executable (to my knowledge) and in all the scratch systems I have seen, It's NOT executable, so it looks like it's just sitting there !

Bob Zelin

Bob Zelin
Rescue 1, Inc.
maxavid@cfl.rr.com


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Chris Murphy
Re: sysctl.conf file ?
on Aug 28, 2013 at 6:56:55 pm

My expectation is that it shouldn't need to be executable as it's a configuration file which only needs to be read during startup. It's a way to make persistent changes to kernel behavior, it's not a file that contains executable code.


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Matt Geier
Re: sysctl.conf file ?
on Aug 28, 2013 at 7:02:00 pm

Hey Bob,

I really have no clue about Assimilate Scratch product requirements.
It's possible this file is installed because - it's part of the fact it's a BSD file format.

It's a configuration file.
You can bring up a terminal on the mac and type 'man sysctl.conf' and you should get something that explains how this is used in general.

Example of what comes up in the terminal with the man command;

SYSCTL.CONF(5) BSD File Formats Manual

NAME
sysctl.conf -- kernel state defaults

DESCRIPTION
The /etc/sysctl.conf file is read in when the system goes into multi-user mode to set default settings
for the kernel. The /etc/sysctl.conf is in the format of the sysctl(8) command, i.e.

The sysctl command, is used to set kernel states.....this file is used to often keep kernel states, so when a machine is rebooted for example, the kernel parameters stay....(much like what's needed for 10GbE network tuning...)

You can also do a "man sysctl" and read about the actual command.

You may know all this already.
I don't think I'm being helpful to you, but maybe more then I realize.

--- It's possible that the application developers in this case, have the file there, just in case they need to do debugging etc if a problem comes up.... sysctl is also used to set up kernel debugging paramters for specific kernel events ---


Again, if you know this or have an idea better then I do about it, no harm done I hope....I'm just trying to help in a very basic way...

I did take the time to search around for anyone using this file in conjunction with the application, and cannot find anything to any degree except for your original post about this file living where you've found it......

As long as there's nothing in the file set, certainly deleting it won't create havoc ... but then again, if there is something in Assimilate calling the file to look at during it's start up or system boot sequence, and then it cannot find it, that could create issues like any missing file would potentially.

Matt Geier
651-808-1338
(Creative Product Evangelist)
(Technical Sales Consultant)
(Video Networking Solutions Consultant)
(Creative Design Workflow Consultant)
(Social Media Networks Consultant)


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Chris Murphy
Re: sysctl.conf file ?
on Aug 28, 2013 at 7:06:13 pm

I just checked on RHEL and Fedora linux, and the permissions for this file is 0644 or -rw-r--r--. The contents can be paged through with spacebar using:

cat /etc/sysctl.conf | more


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Bob Zelin
Re: sysctl.conf file ?
on Aug 28, 2013 at 8:31:49 pm

ok, since you seem to be so interested, and no one from Assimilate is responding (I emailed Nacho at Assimilate and have not heard from him, or Lucas) -

I believe that it is related to a PostgreSQL file that Assimilate is using. I am ignorant of what Assimilate Scratch is doing with a database in their program, but I certainly don't want to screw up my clients machine.

This is the contents of the file (sysctl.conf) - obviously this has nothing to do with network tuning -

kern.sysv.shmmni=256
kern.sysv.shmseg=64
#settings for Assimilate Scratch
kern.sysv.shmmax=268435456
kern.sysv.shmall=65536


SO, since I know nothing about PostgreSQL, and since I don't want to "break" my clients system (which runs Assimilate Scratch), I am simply asking the question - what happens if I replace this file.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
maxavid@cfl.rr.com


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Matt Geier
Re: sysctl.conf file ?
on Aug 28, 2013 at 9:42:10 pm

Bob,

My first reaction to this is leave it alone.

The #settings line is commented out and isn't going to be recognized as a variable when the system boots up.

The rest however are recognized on boot: (i believe, because they are in the sysctl.conf file...)
These settings it's showing you are Shared Memory values;

Mac OS X Server v10.6 client who access applications that use shm_open(2), sometimes called System V Shared Memory segments, may need to configure resources for shared memory. For example, postgres and other databases may require tuned allocations of these resources.

Is Assimilate on a Server in this case?
Is it being accessed over a network from a client system?
You said it's using a Database of some kind... I'm guessing that's why this file and these settings live there...to support that..

I would write the variables down, so i know what they are..and then add a # sign in front of each line to "comment it out" .. ....effectively if you comment out the lines, you can always go back and uncomment them one by one, or all at once if something goes arry.

Info on Shared Memory Values in Mac OS X Server
Shared memory segments in Mac OS X Server are configured via sysctl variables. These variables are:

kern.sysv.shmmax - Maximum size in bytes of all shared memory segments
kern.sysv.shmmin - Minimum shared memory segment size (bytes)
kern.sysv.shmmni - Maximum number of shared segments, system-wide
kern.sysv.shmseg - Maximum number of shared segments, per-process
kern.sysv.shmall - Maximum number of pages allocated to shared memory segments, system-wide


Setting values

In order to use segments larger than 128 MB, hardware that supports the 64-bit kernel in Mac OS X Server v10.6 is recommended. To determine if your hardware supports the 64-bit kernel, see this article. When using the 64-bit kernel, the primary limitation for the size of shared memory segments is the amount of physical RAM in the server. When planning the amount of memory to allocate to shared memory segments, you must account for memory used by the system as a whole.

For example, your server might use:

512 MB - wired kernel memory
3.8 GB - resident memory in use by all applications not counting shared memory segments
1 GB - Shared memory regions
5.3 GB - sum of the above

In this example, at least 6 GB of physical RAM is required to support a single 1 GB shared memory region. Additionally, page tables and virtual memory require additional memory, so a 1 GB Shared Memory segment shared across 500 processes will require far more than 1 GB.

To change the values of the variables listed above, create the file /etc/sysctl.conf with lines of text in this format:

kern.sysv.shmmax=1073741824

The example above will increase the maximum amount of shared memory size to 1 GB (1073741824 bytes). Use a separate line to set the value for each variable that will be changed from the default.

After creating the file, restart the server so the new values take effect.

Source: http://support.apple.com/kb/HT4022
This article has been archived and is no longer updated by Apple. - Last Modified Aug 2 2013

There's also an article from 318 that might help too;
http://techjournal.318.com/general-technology/shared-memory-settings-explai...

Again - just a lot of info on where this might be leading you. Maybe you've found all this out.

Your best bet would be to work with Assimilate and ask them the question about why this file is there, is it needed for what reason, etc... --- but you'll have to wait for them to advise you on their config settings.

Otherwise...you run a risk...which you know.

Matt Geier
651-808-1338
(Creative Product Evangelist)
(Technical Sales Consultant)
(Video Networking Solutions Consultant)
(Creative Design Workflow Consultant)
(Social Media Networks Consultant)


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Chris Murphy
Re: sysctl.conf file ?
on Aug 29, 2013 at 12:18:38 am

Probably nothing catastrophic, although it may cause the database to slow down somewhere between a little and a ton. Instead of replacing it, presumably with another sysctl.conf with other settings, you can merge them also with cat:

sudo mv /etc/sysctl.conf /etc/sysctl.conf.bak
sudo cat /etc/sysctl.conf.bak new.conf > /etc/sysctl.conf
cat /etc/sysctl.conf

So that'll rename the original to .bak, then use it as file1 and concatenate with file2 and output as a single file3. And the last command displays the result. I'd make sure new.conf has a line break to start with or the concat might put the first line of file2 right at the end of the last line of file1 instead of on its own line.

Or just rename it if you don't intend to replace. That'll disable it without deleting it.

Or leave it alone.


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Bob Zelin
Re: sysctl.conf file ?
on Aug 29, 2013 at 7:12:30 pm

Chris Murphy -
I am lucky that you are here.

Thank you.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
maxavid@cfl.rr.com


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