Author Archive for miljan

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12
Jul

AIX 6 ready for download!

By miljan 4 Comments
Categories: IBM, News and UNIX

Like I previously announced, IBM AIX 6 Beta will be openly available for free download and testing. This time has come and you can start downloading it right now from this page. More info here.

AIX 6 should bring a lot of new stuff especially when it comes to virtualization and high-availability issues. Some new features are ported directly from fault-tolerant systems which should provide even more stable and reliable systems. There will be no official support for Beta testing, but you can ask for help on one of the IBM forums.

Openness of IBM is a pretty new thing. This change in IBM policy is probably influenced by SUN’s opening of Solaris to the community. But even though some changes started, IBM is still far away from OpenSource and from opening code of it’s product to the OpenSource community. And that is a pity because I would really like to see the same usability features on some other UNIX operating systems. Sadly, even Linux is far behind AIX when it comes to usability.

10
Jul

Snow in Buenos Aires

By miljan 2 Comments
Categories: Life and News

Yesterday Buenos Aires received first snowfall in 89 years! As I don’t watch TV or any other form of news, I would probably never hear about this if Tatiana didn’t surprise me this morning with information about the snow. The news is even more surprising since Marica and I were visiting her two years ago at approximately same time of the year and the weather was everything but cold. We wore shorts and t-shirts all the time, even in the evening, and we used to sunbath under the Obelisco.

This seems to be one of the coldest winters in South America in a long, long time. Global worming works in strange ways, indeed. While you think about it enjoy in the pictures of beautiful Buenos Aires covered in snow.

Buenos Aires in Snow

Buenos Aires in Snow

Photos are courtesy of Jeff.

10
Jul

DIA from SQL

By miljan 0 Comments
Categories: Linux

Today I needed a fast way to generate DIA diagram from an MySQL database structure and I found this great little project on SourceForge called, very convenient, sql2dia. This tool is actually a PERL script which generates XML file (yes, if you ever wondered, DIA file format is pure XML. Nice, a? :)) sql2dia does not provide support for relations between tables, but this feature is planed for the future releases. Anyway, it does exactly what I needed it to do – create a diagram of tables in my PostfixAdmin database (don’t ask why… yet :)). Here is an example how it works and the result.

[ home sql2dia ] # ./mysql2dia -D -d maildb -h localhost \
> -u username -p password -o mail.dia
Debug mode activated.
Creating header…
Creating object admin…
Creating object domain…
Creating object vacation…
Creating object mailbox…
Creating object log…
Creating object alias…
Creating object domain_admins…
Creating footer…

sql2dia

08
Jul

32 * 2 = 16h

By miljan 1 Comment
Categories: UNIX

Last week I had an interesting assignment, upgrading one AIX 5.2 server from 32bit to 64bit kernel. Process should be pretty straight forward and is very nicely explained in AIX documentation, but as usual, all actions that require application stopping have to be done after working hours – in this case after 9pm. Considering that all changes, system reboot and application start/stop sequence should not take more than 45 minutes this is not a big problem. As many times before, I didn’t count on good ol’ friend of all system administrators – Murphy.

But, let’s start from the start. First thing I did was to check if the server supports 64bit environment and what version of the kernel is currently running.

# bootinfo -y
64
# bootinfo -K
32

So, the hardware on this server is 64bit (as expected) and active kernel is 32bit. Now, let’s stop applications. Only important application on this server is a production Oracle database. We have to stop it before reboot. (Important thing to note at this moment is the version of database, it is old 8.1.7.4 release of Oracle.)

# su – oracle
% sqlplus /nolog
   
SQL*Plus: Release 8.1.7.0.0 – Production on Wed Jul 4 21:01:20 2007
   
(c) Copyright 2000 Oracle Corporation. All rights reserved.
   
SQL> conn / as sysdba
Connected.(
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> exit
Disconnected from Oracle8i Enterprise Edition Release 8.1.7.4.0 – Production
JServer Release 8.1.7.4.0 – Production

In order to be able to execute 64bit binaries we must edit /etc/inittab so the syscall64 kernel extension is loaded during the boot. This is need even with 64bit kernel.

# mkitab “load64bit:2:wait:/etc/methods/cfg64 >/dev/console 2>&1″

The switch to 64bit kernel is done by simply relinking paths to the kernel and libraries, and updating boot image on the boot device. Followed by a reboot. Simple as that.

# ln -sf /usr/lib/boot/unix_64 /unix
# ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix
# bosboot -a
# shutdown -Fr

After the reboot, I checked the version of running kernel to see if the change actually took place.

# bootinfo -K
64

Perfect! so simple isn’t it. I just love when things go so smoothly. Now let’s start Oracle.

# su – oracle
% sqlplus /nolog
Could not load program sqlplus:
Symbol resolution failed for sqlplus because:
Symbol pw_post (number 272) is not exported from dependent module /unix.
Symbol pw_wait (number 273) is not exported from dependent module /unix.
Symbol pw_config (number 274) is not exported from dependent module /unix.
Symbol aix_ora_pw_version3_required (number 275) is not exported from dependent module /unix.
Examine .loader section symbols with the ‘dump -Tv’ command.

“Argh, this can’t be happening!” I was thinking, so I tried again. Surprisingly, that didn’t help. After the initial shock, I looked at the message more carefully and tried to figure out what the hell it meant. Kernel doesn’t support necessary Oracle symbols – so maybe the Oracle kernel extension is not loaded, let’s check.

# loadext -r
   
Oracle Kernel Extension Loader for AIX
Copyright (c) 1998,1999 Oracle Corporation
   
sh: /usr/sbin/crash: not found
No Kernel Extension is currently running.

I was on a right trail. But this is strange, Oracle kernel extension is loaded from /etc/inittab during the boot, it SHOULD be loaded. Maybe the inittab got corrupted.

# lsitab -a|grep ora
orapw:2:wait:/etc/loadext -l /etc/pw-syscall

It is there. In the agony I thought maybe syscall64 extension was not loaded so it failed (although it should not matter).

# genkex|grep syscall
4635e70 390 /usr/lib/drivers/syscalls64.ext

It is there. Let’s try to call it manually, maybe it will work now.

# loadext -l /etc/pw-syscall
   
Oracle Kernel Extension Loader for AIX
Copyright (c) 1998,1999 Oracle Corporation
   
Kernel Extension Version: 3
SYS_SINGLELOAD: Exec format error
kmid: 0 (0×0)
path: ‘/etc/pw-syscall’
libpath: ”

Maybe, this extension does not support 64bit environment?

# strings /etc/pw-syscall|head -3
Kernel Extension Version: 3
$Revision: 1.9 $
Supported Oracle Instances: 32-bit & 64-bit

Now I am puzzled even more.

At this point I felt stuck. Reverting back to 32bit kernel was not even an option as this was only one part of the big migration process on this server. But, on the other hand Oracle has to be up and running by morning – this is a very important production server. As I am not an Oracle guru and there was no one from DB team around to ask for advice, I asked Google for help. As many times before, it proved to be wise choice. People already had this problem and solved it by applying small patch for Oracle.

Important thing here is that Oracle version 8 does not support 64bit kernel on AIX. It requires patch number 2896876 in order to do so.

After applying this patch you get a new kernel extension which loads without complaining.

# genkex|grep syscall
466c850 1218 /etc/pw-syscall64
4641ec0 390 /usr/lib/drivers/syscalls64.ext

Now, let’s try to start Oracle.

# su – oracle
% sqlplus /nolog
   
SQL*Plus: Release 8.1.7.0.0 – Production on Thu Jul 5 00:47:45 2007
   
(c) Copyright 2000 Oracle Corporation. All rights reserved.
   
SQL> conn / as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.
   
Total System Global Area  178704276 bytes
Fixed Size                    73620 bytes
Variable Size             135630848 bytes
Database Buffers           41943040 bytes
Redo Buffers                1056768 bytes
Database mounted.
Database opened.
SQL> exit
Disconnected
% ^D

Nice. :) Next thing is to change inittab to load new Oracle kernel extension,

# chitab “orapw:2:wait:/etc/loadext -l /etc/pw-syscall64″

stop oracle and reboot server again to see how it will behave after the reboot. Luckily everything works fine so at 01am I can finally go home. It was about time since I was there for almost 16 hours (hence the subject of the post.) Ah, the pleasures of being a system administrators are flexible working hours, isn’t it? :)

01
Jul

Usability… WTF is that?

By miljan 0 Comments
Categories: Rant and UNIX

One of the very important things when it comes to software development is usability. Software should be user friendly and easy to use. Despite sustained opinion software for system administration should not be an exception. After all, system administrators are still humans (although some people don’t agree with that :). So it was always a mystery to me why some OS developers, or at least developers of user space tools, try to complicate it as much as they can.

Perfect example for this is Veritas Volume Manager. Other UNIX LVM technologies provide very logical and simple to use tools for LVM administration, but seems that VxVM has “the more confusing – the better” philosophy. Perfect example for this is simple activity of checking how much free space is left in Disk Group (Volume Groups are called Disk Groups in Veritas Volume Manager :)).

# vxdg -g rootdg free
GROUP  DISK     DEVICE   TAG    OFFSET   LENGTH  FLAGS
rootdg rootdisk c1t0d0s2 c1t0d0 46595904 96722880 -

Now, all fields are self explanatory, but WTF are Offset and Length?! Well, Offset is the number of the block where free space begins and Length is size of the free space in blocks. I agree this is very informative and useful output, but why naming fields like this? Why not use simple names like for example “Used space” and “Free space”? Hm, beats me.

But fun doesn’t end there. In case you don’t have free space in your Disk Group vxdg command will not inform you about that, it will just output the header and exit. Very user friendly, isn’t it? :)

Don’t get me wrong, I am not saying VxVM is a bad piece of software. I think it is very powerful and with features that many other Volume Manager software lacks. But, people at Symantec could really hire some usability expert to work on VxVM, it would be a challenge of a lifetime. :)

28
Jun

Take money and run

By miljan 2 Comments
Categories: General and Life

Inspired by “great” experience of people who visited RHCP concert in Serbia, I decided to compare it with one concert I’ve visited this week.

The band I went to see is NoMeansNo – legendary Canadian punk-jazz-rock band (for those who don’t know NoMeansNo, their music sounds like Primus playing Punk), formed almost 30 years ago, they are even older than RHCP. They played in a small club in Brno for approximately 400-500 people. The price of the ticket was 10 euros. RHCP played in an open field with 19 meters long stage in front of more than 100.000 people. Ticket – 40-50 euros.

NoMeansNo live

NoMeansNo started interaction with the fans the moment they got on the stage. Little jokes while setting up the the instruments were enough to make crowd smile. I started smiling the moment I saw how old they are. :) But with the first song they broke all my illusions that they are too old to give a good and fun concert. It was amazing how much energy they have despite their age. And the club they played in can not be called a perfect place for concerts – it was too damn hot inside! With the combination of good humor, good music and high amount of energy from their side the concert prove to be a real hit. I will go to see them again whenever I have the chance although I am not their greatest fan.

NoMeansNo

On the other side, RHCP came to the concert 50 minutes late, started playing with no interaction with the crowd, played with no interaction with the crowd and ended playing with no interaction with the crowd. Not even a “Thank you” for the end. Not to mention they didn’t play their most known hits but some songs known only to them. The singer even forgot the lyrics of some songs. People came from Slovenia, Croatia, Bulgaria and even from Israel to see this concert, and they went home after 70 minutes of total disappointment.

Moral of this post is that excuses like “They are old, you can’t expect them to play like when they were in their 20′s” people usually say for bands like RHCP are not true. NoMeansNo and other bands I had a chance to see live, like Napalm Death and Toy Dolls or even crazy Iggy Pop, all even older than RHCP, are more than capable of giving a really good show if they are not there only to take the money. RHCP obviously does not belong in this category.

Download: NoMeansNo – I’m An Asshole
25
Jun

The School of Assassins

By miljan 0 Comments
Categories: General

One of the better songs I heard in a long, long time. Lyrics here.

Download: Anti-Flag – The School of Assassins

18
Jun

Hanging yum

By miljan 2 Comments
Categories: Linux

Yesterday I noticed a very strange problem with yum on my Fedora 6 notebook. It just plays dead after “Excluding Packages in global exclude list” message. This was not my first problem with yum but this one is the weirdest so far.
Without a clue what could cause such problem I used strace (tool I usually use when I have no clue why some software fails :)) to see if the process is really dead or it was actually doing something. Here is what I got:

[ home ~ ] # strace -p 12085
Process 12085 attached – interrupt to quit
futex(0x9fcc7b8, FUTEX_WAIT, 1, NULL …>

OK, so it was really stuck. And it was stuck on a futex system call which probaly means that yum didn’t exit cleanly on previous run, although I don’t remember it failed recently. As a matter of fact, two weeks ago I rebooted my notebook for the first time in 70 days (what I am trying to say is that it works perfectly :)

Anyway, simple google search on futex and yum reveals more users with similar problem. It seems that the source of the problem is corruption of RPM databases in /var/lib/rpm folder. Problem can be resolved in two ways. Either remove all ‘__db.*’ files from /var/lib/rpm folder or run /usr/lib/rpm/rpmdb_recover.

I somehow prefer the first solution – it gives more satisfaction. :)

29
May

Velikim koracima napred

By miljan 0 Comments
Categories: News

Power6Prethodnih par nedelja su bili dosta burni za IBM – izbacena je nova serija Power procesora a u isto vreme najavljen je i slobodan download nove verzije AIX-a. Novi p6* procesor je, kako tvrdi press release, najbrzi procesor trenutno dostupan. S’ obzirom da je u pitanju dual core procesor brzine 4.7GHz i kesom od 8MB nesto mi govori da je vest tacna. :) Ono sto je vrlo interesantno je da iako su performanse novog procesora skoro duplo bolje od njegovog prethodnika elektricna potrosnja je ostala na nivou “starog” p5* procesora. Ne znam kako su to uspeli ali svaka cast. :)

AIX LogoNovi AIX (6.1) se trudi da iskoristi sve mogucnosti novog procesora. Tako, na primer, uvodi novu tehnologiju zvanu WPAR (Workload Partitions) koja omogucuje da se aplikacije, pa i citav operativni sistem, prebaci sa jednog servera na drugi – bez restarta sistema tj. aplikacije. Ovo ce IBM-u doneti veliku prednost na High Availability trzistu. Vecina HA klastera su uglavnom zamisljeni kao fail over klasteri – u slucaju gubitka servera kriticna aplikacije se prebacuje na novi server i nastavlja sa radom. Medjutim, cak i sa najbolje odradjenim scenarijom postoji odredjeni downtime koji se ne moze izbeci – vreme dok se ne uoci gubitak servera i vreme koje je potrebno da se aplikacija startuje na novom serveru. U idealnoj situaciji ovo vreme bi bilo oko minut-dva sto je opet u odredjenim situacijama previse. WPAR (virtuelna verzija LPAR-a :)) tu dolazi kao ispomoc HACMP-u i skracuje taj neizbezni downtime na najmanji moguci minimum – detekciju propustenih heartbeat-ova. BTW, za par mesceci se ocekuje i nova verzija HACMP-a koja bi trebala da podrzi ove nove funkcionalnosti.

Inace, kao sto rekoh, beta verzije AIX-a namenjene za testiranje, ce po prvi put biti javno dostupne za skidanje, pa ko voli nek izvoli. :) Vise informacija mozete ocekivati uskoro na adresi http://www-03.ibm.com/servers/aix/.

* p ne stoji za pentium vec za power. :)

22
Apr

O svemu po malo…

By miljan 2 Comments
Categories: News

Ja sam jedan od onih ljudi koji su jako posveceni svom poslu, sto je, uglavnom, jako pozitivna strana. Medjutim, to ponekad dovodi do toga da mu posvetim sve svoje vreme. Tako da se ponekad desava da na poslu ostanem i po 10-12 sati i da uopste me primetim koliko je vremena proslo. I kao da to nije dovoljno, cak i kada dodjem kuci posle jednog takvog dana, moj mozak kao da ostane u kancelariji i idalje analizira i pokusava da resi probleme na koje je naisao, ili razmislja o obavezama koje ga cekaju sutra. Naravno, ovakvo ponasanje povremeno dovodi do kratkog spoja koje se ogleda u nemogucnosti koncentrisanja na bilo koju aktivnost slozeniju od brojenja mrtvih piksela i fleka na monitoru (a i tu se zagubim negde posle 15 :)). Otkrio sam da su video igrice savrsen lek za tu otupelost. :) Ali ne bilo koje igrice. To moraju biti neke sa dovoljno dobrom pricom da drzi paznju ali sa druge strane sa dovoljno nasilja da se izbace sve frustracije. Naravno, takva igrica ne sme sadrzati neke mozgalice ili glavolomke (osim ako se ne misli bukvalno :o)) jer moj premoreni mozak to ne moze da svari.

Kao savrsen primer jedne takve igrice je recimo ‘Godfather.’ Radjena po istoimenom filmu, igrica nas vodi kroz svet podzemlja i uspon mladog gangstera – od obicnog ulicnog huligana do sefa njujorskog podzemlja. Usput, mozete da bijete prolaznike na ulici (ima jedan koji se stalno pojavljuje a neverovanto lici na jednog kolegu sa posla koji me uzasno nervira – sto njega voooolim… :)), pljackate banke, gazite policajce kolima i sve ostale sto vas cini srecnim. :) Nakon par sati izivljavanja nad pripadnicima suprotnih “porodica” i slucajnim-i-nicim-izazvanim prolaznicima mozak pocne ponovo da funkcionise. I onda sve opet u krug…

Jos jedna stvar koja me jako opusta i pomaze u koncentraciji je muzika. O tome sam vec pisao pa da ne smaram opet. Samo da napomenem da sam naisao na jos jednog favorita. Ignite, sa svojim novim albumom (novim za mene jer sam tek pre par nedelja naleteo na njega, inace izasao pre godinu dana) je ponovo pomerio granice. Iako vidno komercijalniji nego ranije, znatno su brzi i ubitacno dobri. Pevac Zoli (inace madjar :)) koji je nekada gajio heavy metal glas, sada ipak vise lici na “pravi” melodicni punk/hardcore vokal a i muzika nije vise onako tvrda. Njihov raniji zvuk (pesma, tekst) mi je nekako drazi, ali i ovaj “novi” (pesma, tekst) je takodje za svaku preporuku. :)

Proslog vikenda sam imao virgin iskustvo patch-ovanja HP-UX klastera. Ono sto je ceo proces ucnilo dodatno zanimljivim je i to sto su to bili serveri jedne velike svetske banke, tako da bi svaki downtime bio vrlo vrlo skup. :) Moram priznati da su mi se dlanovi znojili kada sam pritisnuo enter za reboot prvog noda. Nodovi u klasteru (njih 5) su inace zadnji put bili resetovani pre vise od godinu dana i mogucnost da se neki od nodova ne podigne su bili dosta visoki. Srecom HP pravi jako kvalitetan hardware pa osim manjih problema sa (do)konfiguracijom klastera nisam imao znacajnih poteskoca. I nek mi posle neko kaze da je IT dosadan – taj dan sam bio puniji andrenalinom nego kad sam se peo na Rilu! :)

Zamenio sam deo sajta pod nazivom ‘Tips & tricks‘ MediaWiki-jem. Homemade CMS koji sam do sada koristio se nije pokazao kao dovoljno fleksibilno resenje pa je otisao bogu na istinu. Zamenio ga je odlican wiki (koji se inace ovde ne koristi kao wiki vec kao CMS :)) i vec ima dosta tekstova, pa ko voli nek izvoli. :)

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