10-24-2011
Quote:
Originally Posted by
achenle
Hmm, I wonder what happens if you try to read a few GB from a SAN-based file system built on 4 or 6 or maybe more parallel LUNs configured by someone who knows how to lay out storage, and attached with 8 gbps fiber?
Do you really think the VM manager in your kernel can keep up with data coming in that fast?
Guess what? It can't.
Heck, I've seen well-designed 2 gbps SANs with just a few LUNs overwhelm VM managers.
In other words, YES, there ARE reasons to memset() a chunk of RAM *before* you use it.
And that's not even addressing the default Linux method of allowing oversubscription of virtual mamory in the hope that it won't all be used. If reliability and deterministic behavoir are important to you, you don't rely on hope and things like the Linux OOM killer are crazy-bad.
I'm not sure what you're getting at here.... Are you saying the reason to call memset is to assist the VMM in keeping up with a fast transfer?
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Hey guys, need some help. Running AIX Version 5.2 and one of our cron jobs is writing errors to a log file. Any ideas on the following error message.
Error: Internal system error: Unable to initialize standard output file
I'm guessing more info might be needed, so let me know.
Thanks (2 Replies)
Discussion started by: firkus
2 Replies
2. Programming
Hi
Having a lil trouble with a rather simple application I'm writing. It so happens that I have to copy some data using memcpy() and so far I've been doing just fine compiling it with VC.Net and running it on Windows XP. Now I'm trying to port the thing to Solaris (which shouldn't really be too... (3 Replies)
Discussion started by: khoma
3 Replies
3. UNIX for Dummies Questions & Answers
hi there
i write one awk script file in shell programing
the code is related to dd/mm/yy to month, day year format
but i get an error
please can anybody help me out in this problem ??????
i give my code here including error
awk `
# date-month -- convert mm/dd/yy to month day,... (2 Replies)
Discussion started by: Herry
2 Replies
4. Programming
Hi ,
I am having records in a file like
00412772784705041008FRUITFUL STRWBRRY
00412772784703041008FRUITFUL STRWBERE
00000570632801448078 X
i have declared a structure like
typedef struct {
char Uname;
char Pname;
... (4 Replies)
Discussion started by: arunkumar_mca
4 Replies
5. AIX
--------------------------------------------------------------------------------
Hello, help me please.
I am trying to create a mksysb bakup using nim. I am geting this error, how to correct it ? :
Command : failed stdout: yes stderr: no... (9 Replies)
Discussion started by: astjen
9 Replies
6. Programming
Hello everybody,
I'm coding a test program for ARP protocol, and i don't know why i'm getting a SIGSEGV, i traced it with gdb and it says it's due to the memcpy function from /lib/libc.so.6.
Program received signal SIGSEGV, Segmentation fault.
0xb7e9e327 in memcpy () from /lib/libc.so.6
This... (5 Replies)
Discussion started by: Zykl0n-B
5 Replies
7. UNIX for Dummies Questions & Answers
im kinda new to shell scripting so i need some help
i try to run this script and get the error code
> 5 ")syntax error: operand expected (error token is "
the code for the script is
#!/bin/sh
#
# script to see if the given value is correct
#
# Define errors
ER_AF=86 # Var is... (4 Replies)
Discussion started by: metal005
4 Replies
8. Solaris
I have two servers with a fresh install of Solaris 11, and having problems when doing rpcinfo between them. There is no firewall involved, so everything should theoretically be getting through. Does anyone have any ideas? I did a lot of Google searches, and haven't found a working solution yet.
... (2 Replies)
Discussion started by: christr
2 Replies
9. Shell Programming and Scripting
Dear All,
I am trying to compile OpenFOAM-1.7.x in RHEL. I could not able to compile some of the applications because of libc version issues.
It is saying
undefined reference to memcpy@GLIBC_2.14
Can anybody look into it?
Thanks & Regards,
linuxUser_ (3 Replies)
Discussion started by: linuxUser_
3 Replies
10. UNIX for Beginners Questions & Answers
I am writing a shell script with 2 run time arguments. During the execution if i got any error, then it needs to redirected to a error file and in console. Also both error and output to be redirected to a log file. But i am facing the below error.
#! /bin/sh
errExit ()
{
errMsg=`cat... (1 Reply)
Discussion started by: sarathy_a35
1 Replies
CTLD(8) BSD System Manager's Manual CTLD(8)
NAME
ctld -- CAM Target Layer / iSCSI target daemon
SYNOPSIS
ctld [-d] [-f config-file]
DESCRIPTION
The ctld daemon is responsible for managing the CAM Target Layer configuration, accepting incoming iSCSI connections, performing authentica-
tion and passing connections to the kernel part of the native iSCSI target.
Upon startup, the ctld daemon parses the configuration file and exits, if it encounters any errors. Then it compares the configuration with
the kernel list of LUNs managed by previously running ctld instances, removes LUNs no longer existing in the configuration file, and creates
new LUNs as necessary. After that it listens for the incoming iSCSI connections, performs authentication, and, if successful, passes the
connections to the kernel part of CTL iSCSI target, which handles it from that point.
When it receives a SIGHUP signal, the ctld reloads its configuration and applies the changes to the kernel. Changes are applied in a way
that avoids unnecessary disruptions; for example removing one LUN does not affect other LUNs.
When exiting gracefully, the ctld daemon removes LUNs it managed and forcibly disconnects all the clients. Otherwise - for example, when
killed with SIGKILL - LUNs stay configured and clients remain connected.
To perform administrative actions that apply to already connected sessions, such as forcing termination, use ctladm(8).
The following options are available:
-f config-file
Specifies the name of the configuration file. The default is /etc/ctl.conf.
-d Debug mode. The server sends verbose debug output to standard error, and does not put itself in the background. The server will
also not fork and will exit after processing one connection. This option is only intended for debugging the target.
FILES
/etc/ctl.conf The configuration file for ctld. The file format and configuration options are described in ctl.conf(5).
/var/run/ctld.pid The default location of the ctld PID file.
EXIT STATUS
The ctld utility exits 0 on success, and >0 if an error occurs.
SEE ALSO
ctl(4), ctl.conf(5), ctladm(8)
HISTORY
The ctld command appeared in FreeBSD 10.0.
AUTHORS
The ctld was developed by Edward Tomasz Napierala <trasz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
BSD
November 9, 2014 BSD