linuxsutra

RRD4SAR

praveenmanja | 29 April, 2010 02:29

RRD4SAR

Description: Fetch SAR statistics for a selected day for a selected remote machine and display them graphically. Uses RRDtool (Copyright 1997-2004 by Tobias Oetiker ), SAR command authored by Sebastien Godard & PHP(libssh2).

License: Distributed under GNU GENERAL PUBLIC LICENSE - Version 3
Author: Praveen Kumar K S
Download: rrd4sar

SVN | Write-Thru-Proxy | Errors & Resolutions

praveenmanja | 30 December, 2008 05:30

Errors & Resolutions

       Install errors and resolutions not covered here.

1)    During svnsync usage
       Error:
               svnsync: PROPFIND of '/MySubversionAmericaServer': Could not resolve hostname `MySubversionIndiaServer'
       Resolution:
               ip instead of hostname

2)
       SVNSYNC troubleshooting:
               Trouble shooting trailing slases in httpd.conf
               I tried Subversion 1.5 Beta1 WebDAV Write-Thru Proxies. Works fine for me.
               While compiling SVN 1.5, it complained about few thing(mostly related to Neon
               and Swig-Python).. which were resolved after I provided it with latest version of Neon and Swig.
               I tried a mirrored(svnsync) setup like:
               A -------------> a
               b <------------- B
               where A,B are masters and a,b are slaves. Later I tried
               checkout-from-mirror-checkin-to-master scenario.
               Works well. It gave me trailing slash related error.

               Resolution:
               In master httpd.conf no trailing slash in location directive:
               <Location /ABCD>
               In mirror httpd.conf has trailing slash in location directive:
               <Location /co-from-mirror-cin-to-master/>
               SVNMasterURI http://masterhost/ABCD/
               ..
               ..
               </Location>

               Complication of the above setup should be noted first.
               On checkout from mirror and checkin to master , this setup does the following.
               1) redirect to master
               2) cin to master
               3) sync to mirror (using svnsync in post-commit wrapper)
               Setup involves svnsync, location directive, SVNMasterURI. So this whole slash
               thing observation may not be a actual problem at all. I may have gone wrong
               somewhere. Anyways.. as I said.. it was resolved with no further problem.

               master: noslash
               mirror: slash
               SVNMasterURI: slash
               =OK

               master: noslash
               mirror: slash
               SVNMasterURI: noslash
               =svn: Unusable URI: it does not refer to this repository

               master: noslash
               mirror: noslash
               SVNMasterURI: slash
               =svn: Server sent unexpected return value (405 Method Not Allowed) in response
               to PROPPATCH request for
               '/co-from-mirror-cin-to-master!svn/wbl/1e1fafe4-c5f4-48ba-93c3-05646e5b9087/3

               master: slash
               mirror: slash
               SVNMasterURI: slash
               =svnsync: Server sent unexpected return value (405 Method Not Allowed) in
               response to PROPFIND request for '/ABCD'

3)    During cvsus --> MySubversionAmericaServer conversion using cvs2svn
       Error:
               '/home/myname/cvs/cvsroot/dummy/dummy.txt,v' is not a valid ,v file
       Resolution:
               It is an empty file(not required) and can be removed during conversion
               Checkout from mycvsserver says:
               cvs -d :pserver:praveen@mycvsserver:2401/cvsroot co dummy/dummy.txt
                       cvs server: warning: new-born dummy/dummy.txt
                       has disappeared
               cvs -d :pserver:praveen@mycvsserver:2401/cvsroot co dummy
                       cvs server: Updating
                       dummy
                       U
                       dummy/dummy.txt
                mv /home/myname/cvs/cvsroot/dummy/dummy.txt,v /tmp/junk/

       Error:
               It is not clear how the following symbols should be converted.
               Use --force-tag, --force-branch, --exclude, and/or --symbol-default to
               resolve the ambiguity.
                   'ABCDEF' is a tag in 11111 files, a branch in 111
               files and has commits in 222 files
                   'GEFGEF' is a tag in 333 files, a branch in 1111 files
               and has commits in 11 files
       Temporary Resolution:
               --symbol-default="heuristic"

       Error:
               Unable to convert a path
               'whatever.whatever'
               to internal encoding.
               Consider rerunning with one or more '--encoding' parameters or
               with '--fallback-encoding'.
       Resolution:
               --encoding=latin_1
               --encoding=utf_8
               --encoding=utf_7
               --encoding=utf_16
               --encoding=shift_jis
               --fallback-encoding=utf_8

4)    After installing svn-python binding in MySubversionAmericaServer.. while executing
       python
       >>>import svn.repos
       Error:
               undefined symbol: gss_delete_sec_context
       Resolution:
               cd /home/myname/svn-install-scripts/subversion-1.5.0-beta1
               vi Makefile
                       #SVN_APR_LIBS = /home/myname/apache-2.2.6/lib/libapr-1.la -luuid -lrt -lcrypt -lpthread -ldl
                       SVN_APR_LIBS = /home/myname/apache-2.2.6/lib/libapr-1.la -luuid -lrt -lcrypt -lpthread -ldl -lgssapi
               ln -s /usr/lib/libgssapi.so.2.0.0 /usr/lib/libgssapi.so
               And make again.

SELinux, httpd ( apache ), file context ( httpd_sys_content_t ) and other settings

praveenmanja | 04 November, 2008 06:17

SELinux when enforced can make a lot of things not work. Features developed at
an server(SELinux disabled) may not work when it goes to production. SELinux controls
httpd (Apache) and I can list down few pointers for you.
Errors:

You see errors when you try creating a VirtualHost having its DocumentRoot on directories other than /var/www/html
You see errors when you try starting apache on non standard ports other than ones listed below
                        http_cache_port_t              tcp      3128, 8080, 8118
                        http_cache_port_t              udp      3130
                        http_port_t                    tcp      80, 443, 488, 8008, 8009, 8443
                        pegasus_http_port_t            tcp      5988
                        pegasus_https_port_t           tcp      5989
Your script does not execute if you are trying to run system files in it.
Eg:
You are trying to run /usr/bin/crontab, etc from php.

So.. what are we supposed to do? There are two possibilities.

Disable selinux (refer SELINUX Restrictions On Apache). NOT A GOOD IDEA.
Or set SElinux to allow what you wan't

SELinux can be configured by setting selinux booleans and also by changing the context of the scripts. So.. what is this context? You will come to know below.

(More)

Common Errors and Resolutions

praveenmanja | 04 August, 2008 07:34

Common errors, its context and its resolution(fix,dirtyfix):

Error:
rsync: recv_generator: mkdir "" failed: Too many links (31)
rsync: stat "" failed: No such file or directory (2)
rsync: mkstemp ".MXiMwF" failed: No such file or directory (2)
Resolution:
Go for reiserfs or gfs or comply with ext3 subdirectories limitation

Context:
svnsync (reversal)
Error:
svnsync: PROPFIND of '/mysvn': Could not resolve hostname `myhost'
Resolution:
ip instead of hostname

Context:
svn-python
>>>import svn.repos
Error:
undefined symbol: gss_delete_sec_context
Resolution:
(More)

MySQL clustering strategies and comparisions

praveenmanja | 17 April, 2007 12:39

After testing the following strategies of MySQL cluster alternatives, here, are my supplies to open source communities, with out which I could not have tried the following in first place. I have consolidated what I found on net in bits and pieces + some of my experiences.

MySQL Clustering(ndb-cluster stogare)

MySQL / GFS-GNBD/ HA

MySQL / DRBD /HA

MySQL Write Master / Multiple MySQL Read Slaves

Standalone MySQL Servers(Functionally seperated)

(More)

RRD4SAR

SVN | Write-Thru-Proxy | Errors & Resolutions

SELinux, httpd ( apache ), file context ( httpd_sys_content_t ) and other settings

Common Errors and Resolutions

MySQL clustering strategies and comparisions

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