Tag-Archive for » ubuntu «

nedjelja, 4. avgust, 2013 | Author:

istorija

Mnogo se promenio od kada sam zadnji spomenuo moje lični server – ona je porasla za skokovi i granice (ona sada ima 7TB MD RAID6) i da je nedavno obnovljena s ubuntu server.

svod nikada nije bila greška. Arch Linux me je već naučio puno o Linuxu (i da će nastaviti da to učine na moje druge desktop). Ali Arch definitivno zahtijeva više vremena i pažnje nego što bih provesti na serveru. U idealnom slučaju Radije bih da mogu da zaborave na server za neko vrijeme dok se podsjetnik e-mail kaže “a … postoji nekoliko ažuriranja bi trebalo da pogledate, druže.”

Prostor nije besplatan – a nije ni prostor

Priliku da migriraju u Ubuntu bila je činjenica da sam ostao bez SATA portovi, portove potrebne za povezivanje hard diskova na ostatak računara – da 7TB RAID koristi mnogo luka! Ja sam čak i dao mi oduzeti vrlo stara 200GB hard disk, jer je jedan od tih portova. Takođe sam upozorio primaoca da je diska SMART praćenje ukazuje da je nepouzdan. Kao privremeno rešenje na nedostatak SATA portova, Ja sam čak migrirali OS servera na set od četiri USB štapića u MD RAID1. lud. Znam. Nisam bio previše zadovoljan o brzini. Odlučio sam da odem i kupim novi pouzdan hard disk i SATA proširenje karticu koja ide uz njega.

primarni Arch particije poslužitelja je koristio oko 7GB disk. A veliki komad koji je bio razmjena fajl, keširane podataka i inače razni ili nepotrebnih datoteka. Sve u svemu stvarnoj veličini OS, uključujući /Dom folder, bio je samo oko 2GB. To me je zatraženo da pogledam u super-brze SSD pogon, misleći možda jedan manji ne može biti tako skupo. Ispostavilo se da je najjeftiniji non-SSD sam mogao da nađem zapravo trošak više od jedne od tih relativno malih SSD-ove. Yay za mene. 🙂

izbor? woah?!

U odabiru OS, Već sam odlučio da ne bi bilo Arch. Od svih drugih popularnih distribucija, Ja sam najviše upoznat sa Ubuntu i CentOS. fedora je i mogućnost – ali nisam ozbiljno još smatra da je za server. Ubuntu je osvojio krug.

Narednih odluka koju sam morao napraviti nije mi palo na pamet dok sveprisutnost (čarobnjak za instalaciju Ubuntu) pitao je mene: Kako podesiti particija.

Bio sam novi u pomoću SSD-u Linux – Ja sam dobro svjestan zamke da ih pravilno koristi, uglavnom zbog opasnosti od siromašnih dugovječnosti ako zloupotrebljava.

Nisam želite koristiti namjenski swap particije. Planiram na unapređenju matične ploče / CPU / memorija servera ne previše daleko u budućnost. Na osnovu toga sam odlučio da ću staviti swap u swap datoteku na postojećim MD RAID. Swap neće biti posebno brzo, ali njegova jedina svrha će biti za to rijetke prilike kada nešto je krenulo naopako, a memorija nije dostupna.

To me onda ostavio da daju root path punu 60GB iz neke Intel 330 SSD. Smatrao sam razdvajanja / kuće, ali činilo mi se malo besmislena, s obzirom koliko malo je korišten u prošlosti. Prvi put sam postaviti particije s LVM – nešto što sam nedavno radila kad god sam postaviti Linux box (stvarno, nema izgovora da ne koristi LVM). Kada je došao do dijela gdje bih konfigurirati filesystem, kliknuo sam padajući i instinktivno odabrana ext4. Onda sam primijetio btrfs na istoj listi. Drži se!!

Ali ono što?

Btrfs (“maslac-ef-ess”, “bolje eff-ess”, “bee-tree-eff-ess”, ili kako god se sviđa na dan) je relativno novi datotečni sustav razvijen kako bi se donijeti Linux’ filesystem mogućnosti vratiti na pravi put sa sadašnjim fajl sistem tech. Postojeći King-of-the-Hill datotečni sustav, “lokal” (trenutnu verziju pod nazivom ext4) je prilično dobar – ali je ograničen, zaglavi u staroj paradigmi (mislim na potpuno novi F22 Raptor vs. an F4 Phantom sa pokušaj pola Ještěd na nadogradnju ekvivalencije) i teško da će biti u mogućnosti da se natječu za dugo novijim datotečnih sustava Enterprise, kao što su Oracle ZFS. Btrfs još uvijek ima dug put i još uvijek smatra eksperimentalnim (u zavisnosti od toga koga pitate i šta ima ti treba). Mnogi smatraju da je to stabilna za osnovnu upotrebu – ali niko neće da bilo kakve garancije. i, naravno, svi govore da bi i test backup!

Mooooooo

Najosnovnijih razlika između lokal i btrfs je da btrfs je “CoW” ili “Kopiju na Write” sistem podataka. To znači da se podaci nikad nije namjerno prepisuju unutarnji datotečnog sustava je. Ako napišete promjene u datoteku, btrfs će pisati promjene na novu lokaciju na fizičkim medijima i da će ažurirati interne pokazivači da se odnosi na novu lokaciju. Btrfs ide korak dalje u tom te interne pokazivači (nazivaju metapodataka) su takođe CoW. Starije verzije lokal bi jednostavno prepisani podaci. Ext4 će koristiti Journal kako bi se osiguralo da se korupcija neće doći ukoliko AC utikač se izvuče najviše nezgodan trenutak. Časopis rezultira sličan broj koraka potrebnih za ažuriranje podataka. Sa SSD, hardver osnovi vodi sličan proces CoW bez obzira na datotečni sustav koji koristite. To je zato što SSD diskova ne može zapravo prepisati podatke – oni imaju za kopiranje podataka (sa svojim promjenama) na novu lokaciju, a zatim izbrisati stare blok u potpunosti. Optimizacije u ovoj oblasti je da je SSD možda i nije izbrisati stare blok nego samo da napomenem za brisanje bloka kasnije kada stvari nisu toliko zauzeti. Krajnji rezultat je da SSD uklapaju vrlo dobro sa kravu datotečni sustav i ne obavljaju, kao i sa ne-CoW sisteme datoteka.

Da bi stvar bila zanimljiva, CoW u filesystem lako ide ruku pod ruku sa funkciju koja se zove deduplikacijom. Ovo omogućava dva (ili više) identične blokove podataka koji se čuvaju koristeći samo jedan primjerak, uštedu prostora. kravljeg, ako je deduplikaciju datoteka izmijenjena, odvojeni blizanac neće uticati i podaci o modifikovana datoteka će su napisane u različitim fizičkim blok.

CoW zauzvrat marke snapshotting relativno lako sprovesti. Kada se snimak sistem samo snima novi snimak kao dupliranje svih podataka i metapodataka u obimu. kravljeg, kada su napravljene promjene, podataka snapshot-a ostaje netaknuta, i konzistentan obzirom na status fajlsistema je u vrijeme kada je napravio snimak može održavati.

Novi prijatelj

Uz gore na umu, pogotovo što Ubuntu je napravio btrfs dostupan kao install-put opcija, Mislio sam da bi bilo dobro vrijeme da zaroni u btrfs i istražiti malo. 🙂

Dio 2 uskoro dolazi …

udio
Thursday, January 01st, 2009 | Author:

Apparently, what operating system you use can say a lot about you. If you’re using some form of *nix, which distro you’re using can say a lot as well. Redundancy aside, I believe that a Linux distribution depends absolutely on its package management and distribution system.

I liked apt-get (1, 2) but there was some technical problem at some point and it caused me to use aptitude instead. Using aptitude is slightly easierit has more features automated into single, logical, commands where apt-get requires separate commands. Aptitude also has a curses-based GUI. If you’re not using the GUI then, other than brevity in terms of number of commands to learn, there is apparently no technical reason to prefer one over the other. Aptitude and apt-get serve K/X/Ubuntu i Debian dobro. From this point, I use the names Kubuntu and Ubuntu in a loosely interchangeable fashion.

In my use of CentOS (based on Red Hat), I’ve found I like yum. It seems to work in much the same as aptitudeone command to rule them all. It has some rather annoying default behaviour I’m not going to get into here as its most likely because I’m just not used to it. At least from a technical perspective, it is very good. I believe that fedora also makes use of yum though my experience with Fedora is very limited.

the theory

Fedora and Ubuntu are in a class of distributions that have a fairly rigorous release cycle. ubuntu 8.10 (the version is named so for the year and month of its release) will not, except for major bugs and minor changes, have another major update until the next version, Jaunty Jackalope. Ubuntu users have the latest versions of most software on their desktops right now. In the months preceding the next release, however, they’re not going to be so lucky unless they like using “beta” releases. As I’m not very familiar with Fedora, I’m not going to bother going into its release cycle.

These 2 distributions are also within a class of distributions known asbinary” ili “binary-baseddistributions. This means that when you download an update, the files that are downloaded are precompiled and should run on anysupportedhardware. This isn’t specifically optimised for your desktop’s hardware, for example, your processor. Perhaps you have an AMD processor which has extra instruction support which Intel CPUs do not have. The reverse could also be true. For this reason, a binary-release distribution cannot optimise for one particular brand of hardware. Regardless of thisnon-optimisation”, it should run at a decent pace.

the practice!

About 2 years ago I started using Kubuntu. After a few months of working with it, I started to learn more about its specifics. I’m not much of a fan of using GUI tools to update the system when, ultimately, its all happening on the command-line anyway. The GUI tools just hide the complexity I don’t mind seeing.

I ended up making a bash skripta, update, which would run all the steps required to get aptitude to just go ahead and upgrade already, kthx?©, perhaps stopping along the way to back up my configuration, remount the NFS network share where we keep an on-site repository, back up the local cache of aptitude’s installed packages, do some folder-link shuffling to use a local copy if the network share couldn’t remount, sync between the local copy and the network share if the previous update had a network share issue, and update lists of packages in the repository. In general, it wouldn’t go ahead if there were any errors though, as you can tell, this script became a messy beast that went above and beyond the original requirements. It worked well for me.

Until the day came to update between Kubuntu 6.10 do 7.04. I did this manually though, not with the script.

I ended up reinstalling from scratch as a result of the mess that ensued. At least, as a backup administrator should do well to demonstrate, it was easy to recover everything I really needed. 🙂

What else is out there?

Even before I had to reinstall Kubuntu, I was introduced to another distribution called Gentoo. There are 2 very distinct differences between Gentoo and Ubuntu’s update system. The first is that Gentoo is a source-based distribution. This means that when you update a package, the package manager downloads the source and compiles everything, hopefully optimising it for your system. This, I think, is very cool. The downside to this is that compiling everything takes a very long time.

Here are my (very unscientific) estimates for the length of time it takes to install a basic GUI OS to a desktop from installation media, excluding extraneous drivers (for example, the latest 3D graphics drivers):

OS: minmax (median)

Windows Vista: 15 – 30 (20) minutes

ubuntu: 15 – 40 (20) minutes

Gentoo: 3 – 40 (6) hours

Gentoo also requires much tinkering with the config files in order to get things workingthis is another reason for the extremely long delay between inserting the CD and booting your awesome* new desktop. Popular applications have binary packages available for downloadthough this isn’t a default option.

They see me rollin

There is one more very important distinction Gentoo has from most other distributions. It is arolling-releasedistribution. This means that there isn’t any rigorous version orreleasethat the distribution adheres to. If you install Gentoo todayif you finish installing Gentoo today, you’re probably going to have the latest version of all the applications you installed. If some obscure application gets a major update tomorrow, within a few days, if you update your system, you’re going to have that latest version on your desktop.

The difference between this rolling release and theotherdistributions is rather staggering. Na primjer: If KDE 4.2 were to be released tomorrow, you’d probably have to wait less than 2 weeks for it to be available on Gentoo. Ubuntu users might have to wait till 9.04 – that’s a 4-month wait.

Something more suitable?

Personally, I’m not willing to put in the 40 hours of effort to get my system working the way I want it to. My colleague had to reinstall recently for some obscure reason and it turns out he wasn’t willing to put in the 6 hours (he’s more experienced with Gentoo) of effort to get his system back to how it was running either. Instead, Arch Linux caught his eye. Arch Linux is a rolling-release (like Gentoo), binary-based (like Ubuntu) distribution. Its packages (dobro, the vast majority of them) don’t need much tinkering with their config files to get things working nicely either. Its the best of both worlds!

You still need to know what you’re doing* but if you’ve come to this juncture, it shouldn’t be such a giant leap of faith. Arch Linux’s package manager, called pacmuškarac, has built-in dependency and conflict handling. I use another package manager, jogurt (French for yoghurt), which has very quickly become popular with Arch users. Yaourt enhances the functionality of pacman by allowing you to download and install applications directly from the AUR, ili Arch User Repository. This repository contains scripts that allow you to automatically download and install many applications that would otherwise be completely unsupported by Arch’s own core developers. It downloads and compiles the package into a chroot’d environment. It then packages the chroot’d environment into a pacman-compatible package tarball and uses pacman to deploy it into your system.

takođe, the AUR supports a voting system whereby popular packages get placed into the more official [community] repository. Yaourt also supports an automated voting mechanism whereby, after installing a package via AUR, it asks if you want to vote for its inclusion in [community].

I estimate that the time taken for my Arch installation was about 90 minutes. I don’t recommend Archlinux for newbies though I do recommend it for any Linux user who’s gotten bored with other distrosand wants to get into the nitty gritty without having to install Linux From Scratch. Arch Linux has been getting pretty popular these days. Its currently at number 14 na Distrowatch.

* IF you know what you’re doing. AND YOU BETTER BLOODY KNOW WHAT YOU’RE DOING!
udio