Tag-Arhiv za » ubuntu «

Nedelja, 4. avgust, 2013 | Avtor:

Zgodovina

Veliko se je spremenilo, odkar sem nazadnje omenil moj osebni pomočnik – je zrasla z Skoke in meje (zdaj ima 7TB md RAID6) in ga je pred kratkim obnovili s Ubuntu Strežnik.

Arch nikoli ni bila napaka. Arch Linux me je že naučila toliko o Linuxu (in bo še naprej, da to storijo na mojem drugem namizju). Ampak Arch vsekakor zahteva več časa in pozornosti, kot Rad bi, da preživijo na strežniku. V idealnem primeru bi raje, da lahko pozabite na strežniku za nekaj časa, dokler opomnik email pravi “hm … tam je nekaj posodobitve morate pogledati, kolega.”

Vesolje ni zastonj – in noben od njiju ni prostora

Priložnost, da migrirajo na Ubuntu je dejstvo, da je zmanjkalo SATA pristanišča, pristanišča, potrebni za priključitev trdih diskov za preostali del računalnika – da 7TB RAID polje uporablja veliko pristanišč! Imel sem celo dal proč moja zelo stara 200GB trdega diska, kot je vzel eno od teh pristanišč. Prav tako sem opozoril prejemnika, da je disk SMART Nadzor je navedeno, da je nezanesljiv. Kot začasno rešitev za pomanjkanje SATA pristanišč, Imel sem celo preseliti OS strežnika za niz štirih USB ključi v MD RAID1. Crazy. Vem. Nisem bil preveč zadovoljen s hitrostjo. Odločil sem se, da gredo ven in kupiti novega zanesljiv trdi disk in SATA razširitveno kartico, da gredo z njim.

Primarno particijo Arch strežnika je z okoli 7 GB disk. Velik kos, ki je bil swap datoteka, cached podatki in sicer mešanih ali nepotrebnih datotek. Skupna dejanska velikost OS, vključno /domov Mapa, je bilo le okoli 2 GB. To me je spodbudilo, da si v super-hitro SSD voziti, misleč morda manjši, morda ne bo tako drago. Izkazalo se je, da je najcenejši brez SSD disk lahko najdem dejansko stalo več kot enega od teh relativno majhnih SSD. Yay zame. 🙂

Izbira? Woah?!

Pri izbiri OS, Jaz bi že odločil, da ne bo Arch. Od vseh drugih priljubljenih distribucij, Jaz sem najbolj seznanjeni z Ubuntu in CentOS. Fedora pa tudi možnost – ampak nisem še resno ga šteje za strežnik. Ubuntu je osvojil krog.

Naslednja odločitev, ki sem imel, da bi ne prišlo do mene, dokler Vsesplošna (Namestitev Ubuntu je čarovnik) je vprašal mene: Kako ustanoviti predelne stene.

Bil sem na novo uporabo SSDs v Linux – Jaz sem dobro zavedajo pasti jih ne uporabljate pravilno, predvsem zaradi njihove nevarnosti slabe življenjske dobe, če je zlorabljena.

Nisem želel uporabiti posebno particijo swap. I načrt za nadgradnjo strežnika matično ploščo / CPU / spomin ne predaleč v prihodnosti. Na podlagi tega sem se odločil, bom dal swap swap datoteko na obstoječi RAID MD. Swap ne bo posebej hitro, vendar njen edini namen bo za to redka priložnost, ko je nekaj narobe in spomina ni na voljo.

To pa me je pustila, da bi koren pot polna 60GB iz Intel 330 SSD. Razmišljal sem ločevanje / domov, ampak je samo zdelo malo nesmiselno, saj, kako je bila uporabljena malo v preteklosti. Najprej sem ustanovil particijo z LVM – nekaj, kar sem pred kratkim delal, ko sem ustanovil Linux računalnik (Res, da ni nobenega izgovora, da ne uporabljate LVM). Ko je prišel do dela, kjer bi nastaviti datotečnega sistema, Sem kliknil na spustnem in nagonsko izbrali ext4. Potem sem opazil, btrfs v istem seznamu. Počakaj!!

Ampak kaj?

Btrfs (“masla eff-zave”, “bolje eff-zave”, “bee-drevo-eff-zave”, ali karkoli radi na dan) je relativno nov datotečni sistem razvit z namenom, da bi Linux’ datotečni zmogljivosti nazaj na pravo pot s trenutno tehnologijo datotečnega sistema. Obstoječi King-of-the-Hill datotečni sistem, “ext” (Trenutna različica se imenuje ext4) je zelo dobra – vendar je to omejeno, zaljubljen v staro paradigmo (pomislite na novo blagovno znamko F22 Raptor vs. an F4 Phantom s pol Ještěd poskusu nadgradnje ekvivalentnosti) in je malo verjetno, da bi lahko konkurirali za zelo dolgo z novejšimi Enterprise datotečnimi sistemi, kot so Oracle ZFS. Btrfs še dolga pot, še vedno velja za eksperimentalno (odvisno od tega, kdo ste in kaj vprašati funkcije, ki jih potrebujete). Mnogi menijo, da je stabilna za osnovno uporabo – ampak nihče se dogaja, da nobenih jamstev. In, seveda, vsi pravijo, da ga preizkusite varnostne kopije!

Mooooooo

Najbolj bistvena razlika med ext in btrfs je, da je btrfs “CoW” ali “Kopiranje na Pisanje” datotečni sistem. To pomeni, da so podatki dejansko nikoli ni namenoma nadomestijo je notranjost datotečnega sistema je. Če napišete spremembe v datoteko, btrfs napisali vaše spremembe na novo lokacijo na fizičnih medijih pa bo posodobil notranje kazalci se nanašajo na novo lokacijo. Btrfs gre še korak dlje, saj so ti kazalci notranje (besedilu metapodatkov) so Prav tako CoW. Starejše različice ext Preprosto bi prečrtanih podatkov. Ext4 bi uporabil list, da se zagotovi, da ne bo prišlo do korupcije, bi bilo treba vtič AC potegnil ven v najbolj neprimernem trenutku. Je revija za posledico podobno število korakov morali posodobiti podatke. S SSD, Osnovna strojna oprema deluje podoben proces krava ne glede na to, kaj datotečni sistem, ki ga uporabljate. To je zato, ker SSD diski ne more dejansko prepiše podatke – imajo za kopiranje podatkov (s spremembami) na novo lokacijo, in nato izbriše staro blok v celoti. Optimizacija na tem področju je, da SSD morda niti ne izbriše starega bloka, ampak preprosto zapišite za brisanje blok na kasnejši čas, ko stvari niso tako zaseden. Končni rezultat je, da SSD diski dobro prilegajo s kravo datotečnega sistema in ne opravljajo, pa tudi z nevladnimi krava datotečnih.

Da bi zadeve zanimivo, CoW v datotečnem sistemu lahko gre z roko v roki s funkcijo, imenovano deduplication. To omogoča 2 (ali več) identični blokov podatkov, ki se hranijo samo z eno kopijo, prihranek prostora. Z krava, če se spremeni datoteka deduplicated, ločena twin ne bo vplivala, saj bo bilo spremenjeno datoteko v zapisu podatkov na drug fizični blok.

CoW pa naredi izdelavo posnetkov razmeroma enostavno izvajati. Ko se je posnetek sistema zgolj beleži nov posnetek kot podvajanje vseh podatkov in metapodatkov v obsegu. Z krava, Ob spremembah, posnetek narejen Podatki ostane nespremenjena, in jih je treba ohraniti dosleden pogled statusa datotečnega sistema, je ob času, ki je bil posnetek.

Novi prijatelj

Z zgoraj v mislih, še posebej, ker je Ubuntu na voljo kot btrfs namestite času izbire, Mislil sem, da bi bil pravi čas, da se potopite v btrfs in raziskati malo. 🙂

Del 2 kmalu …

delež
Thursday, January 01st, 2009 | Avtor:

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 in 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” ali “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!

O 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 script, 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 da 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 primer: 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 pacman, 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, ali 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.

tudi, 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 o Distrowatch.

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