news | books | gallery | cv | contact

Welcome,

You have reached virtual home page of Gerzic Luka a.k.a stinger. I am a linux/unix admin with 10 years of work expirience. I currently work for DELTA M company in Serbia at Senior Internet Service and Operations Administrator position, also I am part time IT consultant for few major Serbian companies. I am 28 years old and I am rally addict :) This is my ride atm, it's a Citroen Saxo VTS 1.6 16v.

Some bits and personal thoughts

Backpack After few hours of cleaning my room, while discoverying whole lot of stuff all arround the place, finally some clean and usefull working space on my table :) Meanwhile, I was makeing a break from dusting and washing stuff, getting trash out, I though it would be cool if make a pic of contents of my backpack, so here it is. Some 40-some items there, even I was supprised that I had all those items inside :) I'll try to make a list of items inside, after i check how some things are called on english :/ Btw, I must say that Delsey backpack is very good actually, I am very satisfied with pockets, and overall capacity.

Hello, few words after few months of busy trainings ... Last few months where very busy for me. After IBM training in Denver and Atlanta, we did continue our training in Washington DC, New York City and Dallas. It was very interesting and inspiring. You can check out new pics in the Gallery section, and rest of the pics from travel and fun part's are on my facebook account, check them out if you are interested.

FC fun Poke'n few "cheap" fc sw's (Cisco MDS 9124's) for a while :) check out pic.

iPhone :) So much talk and buzz surrounding the iPhone in last few months and I was compelled to get one while we where in New York. It would be very difficult to actually get one (or two) if you are not resident and complete outsider, but I have to thanks my friend for helping me out (you know how you are ;) ). Jailbrake'n, false Activation, flashing firmware and getting new applications on was very easy and fun part. Since I got iPhone my phone bill is going crazy :( it's that good. I become the wireless sniff junkye and not to mention the addiction to be "online" 24/7. If you like to know why, here is one pic that will tell you most why is that. iPhone works perfectly, and customisation is awesome. You should try one! UPDATE: Here is new modyfied version of iphone gui that I really like, it's Digg theme!

Cisco VPN problems (linux/bsd/debian related) You may encounter some problems trying to get vpnc client working with remote cisco boxes. I had encounter few of them and decided to write small text about that. You can download text here.

Desktop OS and software I like This is my personal choice of OS and software I use on daily basis for desktop. My current desktop OS is Ubuntu (Gutsy Gibbon) but highly customised. For desktop manager choice I really like Gnome with lot of art packs :) and with Compiz effects. Regarding the tools, most used would be: Gnome terminal shell (what else?), Mozilla Firefox (obvious), Claws Mail (sylpheed) excellent e-mail client, very stable & fast, Gedit a nice text editor, Ghex simple hex editor, VMWare for testing and some odd compatibility, Wireshark for packet inspection, for CD/DVD recording and iso fun Brasero works like a charm, adobe reader for pdf reading and printing, FileZilla is very easy & fast ftp client for some fast ftp work, and sometimes Gnome Commander for some file transfers, but i really preffer mc much more. For office stuff, of course OpenOffice suite. Multimedia & fun part a set of regular ones: Pidgin, xmms, xine, skype, xchat... There is vast amount of shell tools I use but this was just about some Desktop ones.

IBM Customer story, DELTA M Transition to enterprise Yesterday (13/12/2007.) on the IBM event "System P, recommended hardware for SAP" I held a part of presentation, entitled "IBM Customer story - DELTA M Transition to enterprise" in front of company DELTA M. You can download my presentation here. A picture of event is here and here

Toshiba Tecra A8 notebook internal speaker problem If you have a Toshiba Tecra A8 notebook, and you are (hopefully) running linux, you may notice that you cannot play sound on your internal speakers while audio out is working perfectly (while using for example OpenSuSe 10.1), only thing you should do is: startup Yast, go to hardware, then sound control, edit settings for sound card, and again edit "Use the given boardmodel" settings just add word "basic" (without ""), next next finish and you are done :) enjoy sound! :) UPDATE: ubuntu (7.10) has same problem on Toshiba Tecra A8, solution is allmost the same. All you have to do is: echo "options snd-hda-intel enable=1 index=0 model=basic" >> /etc/modprobe.d/alsa-base

qmail finaly in public domain Some of you know qmail, some probably not, but it's imho the best mta, and for years it was covered by D. J. Bernstein licence, but recently he released source to the public (you can check the announcement on his home page). I though to mention that on my home page since i have been using qmail since 1999, and i am one happy admin.

Back from USA IBM training I'm tired. This was really nice expirience, learned a lot of new stuff, and had some quality time while we where there. Topics covered where on the right level, instructors where good and expirienced, overall well spent time. Here is a pic from the first training with intructor Paul Gerone.

Fujitsu-Siemens Primergy series (FujSimens as I like to call them) After nearly 70-80 servers that me and my collegue deployed in production environments, and after nearly 2 years of service I can strongly advise you NOT to buy any of them. We used RX200 S1,S2 and S3 series, aswell as RX300 S1,S2 and S3 also SX30 (storage box), none of them was without of failures. From nearly 80 servers we returned to service nearly 30 of them, some more then 2-3 times. Disk failures where also the common thing. In some cases we could not use disks from same series of servers since FJS used disks from different manufacturers for same series that had different size (few mb's, so we couldn't replace disks since we used mirroring). In any case, if you are considering order Fujitsu-Siemens servers I would NOT advise that. Try some other brands like IBM or HP for entry-mid range servers since they are much much more reliable. FJS failures are mostly linked to LSI controlers or disks, but few times we seen that motherboards where not finished (some parts missing), we even got servers that are not packed correctly.

Hottest day in Belgrade ... huh it was unofficially 48C in Belgrade! Huh! Today,... it was the hottiest day in my life. Never before it was this hot. Official weathercast was broadcasting that it's ~44-45C today, but that is ofcourse in some forest in shadow, not in middle of the Belgrade town, and specially not on the sun. Somewhere arround 11h today someone made a pic in the town center, and as you can see it was 46C allready! We also had a dry very hot wind blowing thru the whole town. It was a disaster.

Testing failover This nice screeny is a cool illustration for FC & eth failover services provided by redudant VIOS servers. Test was conduced by pulling off FC or eth cables while we maintained data write functions on target LPAR or by shutting down one of VIOS servers. As you can see LPAR maintained connections and VIOS reported failure and recovery of FC paths. It's working! :) yay \o/ btw, you can see that we maintained ~200MB/s transfer rate on the lower right console.

Enterprise level Last few weeks I was very very busy working on new data center project. Here is first pic (not that good quallity) of my notebook that is placed on HMC of IBM DS8300, presenting first AIX bootup sequence on IBM P series, before real AIX installation. Notice that boot kernel is 32bit, while the production kernel (not shown on pic) is 64bit. And btw, nice hexspeak. greetz to mm .)

My _own_ internet home at last After years of various systems that hosted my home page, i finally got some free time to register domain name that will be my own internet home for years to come. I can remember my first days on internet in 1996, and my first internet homepage that was hosted on first ISP here in Serbia, it was really a long time ago. Anyway my new homepage will be on www.gerzic.(com|net). Just to mention some of the ISP's and servers that hosted my inernet homepage: EUNet, fuzzion.dob.co.yu, OpenNet, DrenikNet and DELTA.

HBA FC Multi-path & fail-over solutions in linux environments So far, We have tested only Emulex 4GB HBA's (LPe11000) in multi-path environments and we where VERY displeased with RDAC driver solutions. There is a list of at least 14 LIMITATIONS (local copy) that you will have to somehow overcome (section 1.2 Limitations) if you are going for Emulex HBA's on linux. I am waiting to get my hands on Qlogic HBA's to see if there is a difference in approach (so far on pdf's i got it looks good). More info soon.

Want a cheap SAN storage solution? Be sure to check limits! If you are thinking about cheap SAN storage solution, be VERY SURE to check all kind of limits that may cross your mind. For example, few days ago I found out that IBM DS4700 series have limit of 2TB per LUN, and there is no option to override that even with new fresh microcodes. Storage Manager software will not let you to create bigger LUN then 2039GB no matter what you try to do. Now imagine situation that you have few shelfs filled (each shellf has 16 drives) with 500GB drives and you like to create big LUN with let's say 10TB (with both RAID5 or RAID10). You will need to create 5 LUN's each with 2TB and then use lvm on linux to bond them together. I am creating few big tests to see performance impact's in these situations. Oh my God, are we living in '90's? I thought that we are done with 32bit limits long time ago, it's 2007 ffs!! More info soon.

NFS test for Linux and NetApp FAS270 - Benchmark report 2 years ago I conducted some tests with NetApp storage (FAS270) for DELTA M internal usage. These test where conducted in our test lab in perfect conditions. It's important to say that we had some special needs for NFS and we wanted to overrun NVRAM on FAS270 to see how appliance is going to behave on heavy loads in different conditions. Benchmark report is available now, for download if you are interested to see our results. If you like to discuss our findings you can send me e-mail on lgerzic [at] deltayu [dot] com

main() static vs dynamic Back in 2003 my friend and I discovered some bad optimizations by some compilers and glibc, so we sent e-mail to libc-alpha mailing list, and we got response from mr. Roland McGrath (after we where redirected by mr. Ulrich Drepper) with acknowlage of the problem and we think some of distributions in years to come fixed this problem. It was specially interesting to see that fbsd systems had nearly 10 times smaller static binaryes. Anyhow, here is the original mail post, and here is the local copy.

How about this? Some things really amaze me, these pictures of cableing inside some server/communication rooms are really funny to see, and probably hell to work with. These are good examples how things should not be done. It's good example why one should think in advance before adding more cables without proper cableing practice.

3com w/o respect for RFC822, RFC2821 Some time ago I had some fun with 3com system/management/alert options. If you ever had large number of various switches, specially on remote locations then you probably wanted to have some kind of notifications and info from those appliances. Well, sometimes it's not that easy. Specially when vendor (3com) is not respecting RFC. UPDATE: Few folks asked what did I mean, well folks, 3com appliances "craft" e-mail alerts with Bare LFs at end of msg, and that's clearly not RFC 2821 specification. The best of all is that we got response from 3com that they "know about the problem, and they are not interested to fix it". That's about it.

Inside Cisco PIX 535 firewall appliance Ever wondered how Cisco PIX 535 looks inside? I did, so few months ago I took quick dive inside. Nothing much to see, one would expect much more "power" inside, even big daddy Cisco is calling them off.

Fav's: Slashdot, Digg (My+1), Google, KernelTrap, UnDeadly, TheRegister UK, PirateBay, Wikipedia, ifun.ru, WebPark.ru, VasiNet, XKCD webcomic and many others ...

last update 15/06/2008. created by vi