TWEAK: Performance Tip -- Exclude from AV Scan

When you have been using Windows-based computers long enough you will notice that performance degrades over time. There are a lot of causes to this and disk fragmentation is one of them. But little do users know that what contributes a lot to the degradation is the presence of the anti-virus. Add fragmentation to the mix and the performance decline worsens.

For an average user, however, running without an anti-virus is synonymous with suicide. The performance hit that's a consequence of the anti-virus is more acceptable than having to re-install the OS and recover the files. Anti-virus are created to behave with paranoia as the foremost consideration. And it will be very paranoid -- it will scan every file accessed; it will scan memory; it will scan as you boot; it will scan even when you're not doing anything!

Not everything that is in your computer can be infected by a virus. So it is wise to make your anti-virus a little bit smarter than it was programmed to be. What does this mean? It means, exclude files you know to be safe from being scanned. Plain text files are perfect candidates for this. Anything that is text-based (and don't automatically execute) are generally safe. Their extensions are .txt, .log and the like.

Aside from text-based files, multimedia files like mp3, avi, mp4 and mkv are generally safe, especially if they came from trusted sources. It is wise then to make the anti-virus skip them. Also, the anti-virus is not that friendly with Windows page file. It scans that too! Your computer system can perform better if that file is skipped from being scanned.

McAfee. With McAfee, this configuration is in the VirusScan Console under Tasks > On Access Scanner Properties.

Click on "All Processes" and get to the "Exclusions" tab. There is an Exclusions button that will allow you to control the behavior of the On-Access Scanner module.

ESET NOD32. With NOD32, this configuration can be set by pressing "F5" thus opening the Advanced Configuration menu.

Then go to Computer > Antivirus and antispyware > Real-time file system protection. Click on the Setup button and include all file system extensions.

For directory exclusions, go to Computer > Antivirus and antispyware > Exclusions and put the paths to be excluded from on access scans.

I get good performance from my computer when I set it up this way. There is always a drawing of lines between security and functionality. In the end, what matters is for you have to have your say in the matter.

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FAQ: clock_gettime Error Compiling Xymon Client

"There’s No Such Thing As A Silly Question" -- does the cliche sound familiar? In this part of pimp-my-rig reloaded, technical questions are answered. Mail them to me and I will post the answers here. If you have a better answer, by all means share it with us.

Q. I recently received an email from a previous colleague asking for help regarding errors in compiling XYmon client on a machine running Fedora 13. Yes, the host is a bit old but since the application running is mission critical downtime is not acceptable and putting it under the microscope with a xymon client is a well-thought move.

To give you a better picture of the error, here are a few lines of the xymon client compile, after running "make -s".

(other lines snipped for brevity)
...
timefunc.c: In function âtimespec_textâ:
timefunc.c:140: warning: pointer targets in assignment differ in signedness
timefunc.c:187: warning: pointer targets in passing argument 2 of âaddtobufferâ differ in signedness
/var/tmp/xymon-4.3.7/include/../lib/strfunc.h:16: note: expected âchar *â but argument is of type âunsigned char *â
../lib/xymonclient.a(timefunc-client.o): In function `getntimer':
/var/tmp/xymon-4.3.7/lib/timefunc.c:67: undefined reference to `clock_gettime'
../lib/xymonclient.a(timefunc-client.o): In function `gettimer':
/var/tmp/xymon-4.3.7/lib/timefunc.c:55: undefined reference to `clock_gettime'
collect2: ld returned 1 exit statustfc
make[1]: *** [../client/xymon] Error 1
make: *** [common-client] Error 2

So as you can see, the error is fatal and compilation will not complete successfully. I have been through this error before and made notes of the things done to resolve.

A. Xymon was built to take into account regular expressions on things being monitored -- log files, directory sizes, etc, etc. These files can be monitored by classes and/or pattern matches that can be defined by regular expressions. And for xymon to function properly, the pcre-devel (PERL Compatible Regular Expressions) rpm has to be installed.

So install pcre-devel via yum.

[root@host /var/tmp] yum -y install pcre-devel
Loaded plugins: fastestmirror, presto, refresh-packagekit
Loading mirror speeds from cached hostfile
 * fedora: mirror.cse.iitk.ac.in
 * updates: mirror.cse.iitk.ac.in
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package pcre-devel.i686 0:7.8-3.fc12 set to be installed
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package                   Arch         Version             Repository     Size
================================================================================
Installing:
 pcre-devel                i686         7.8-3.fc12          fedora        278 k

Transaction Summary
================================================================================
Install       1 Package(s)

Total download size: 278 k
Installed size: 0.9 M
Downloading Packages:
Setting up and reading Presto delta metadata
Processing delta metadata
Package(s) data still to download: 278 k
(1/1): pcre-devel-7.8-3.fc12.i686.rpm                    | 278 kB     00:02     
--------------------------------------------------------------------------------
Total                                           271 kB/s | 278 kB     00:02     

Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing     : pcre-devel-7.8-3.fc12.i686 [###########################] 1/1

Installed:
  pcre-devel.i686 0:7.8-3.fc12

Complete!

Once pcre-devel is installed, xymon client will compile with a few warnings that can be ignored. Do a "make install" after compile completes. Run the xymon client via "/home/xymon/client/runclient.sh start". The path /home/xymon is the path chosen when running "./configure.client" (or "./configure -client").

This step is optional, but I found that it solves some issues with other versions of Fedora/RedHat based systems. Before running ./configure, define the environment variable LIBRTDEF. Do it with command "export LIBRTDEF=-lrt"

In running xymon client, pcre-devel is more often than not a major dependency. So better install it before doing the compile.

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