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Nedelja, 4. avgust, 2013 | Avtor:

I had a power outage affect my server’s large md RAID array. Rather than let the server as a whole be down while waiting for it to complete an fsck, I had it boot without the large array so I could run the fsck manually.

Vendar, when running it manually I realised I had no way of knowing how far it was and how long it would take to complete. This is especially problematic with such a large array. With a little searching I found the tip of adding the -C parameter when calling fsck. I couldn’t find this in the documentation however: fsckhelp showed no such option.

The option turns out to be ext4-specific, and thus shows a perfectly functional progress bar with a percentage indicator. To find the information, instead offsckhelp” ali “man fsck”, you have to inputfsck.ext4help” ali “man fsck.ext4”. 🙂

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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 …

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Monday, October 29th, 2012 | Avtor:

Zdi se, da, v neskončni modrosti, Google imajo varnostno funkcijo, ki lahko blokira aplikacije dostop do ali uporaba svoj Google Račun. Vidim, kako je to lahko problem za uporabnike Googla, zlasti njihovih GTalk in Gmail Uporabniki. V mojem primeru je bilo Pidgin imajo težave z Jabber Storitev (ki je tehnično del GTalk). Sem našel rešitev po malo kopanje. Bil sem presenečen, kako star je šlo in kako dolgo je ta funkcija obstaja!

Če želite odkleniti račun in dobite prijavni spletu, uporabite Captcha stran Google tukaj.

delež
Thursday, June 03rd, 2010 | Avtor:

Why I’ve left MTN

So I’ve been shopping around in a non-serious fashion in the last few months trying to figure out how best to leave MTN and how get the best deal for me. I don’t like MTN since I became anirate“, as I might call such a customer in the ISP industry. MTN’s Customer-Service Call Centre had rarely been helpful or knowledgeable on their own systems. The final straw however was when their systems let me screw myself over and Customer Service was as helpful as a dead redshirt:

I had a billing issue where, admittedly, it started of my own fault. MTN has a feature where you can call in to find out the amount owing on your account. Only, as Murphy would have it, this amount was ne the amount owing on the account but the last amount that was billed.

So one month my account was about R900. I called the number, mis-heard R500, paid the amount I thought I should: R500. 15 days later MTN suspended my account. No wrong done, right? Wrong.

First off, I received no notification of any kind. An sms would make the most sense, especially since it would cost MTN almost no resources: “Your account xyz is in arrears by R400. Please contact blah blah blah”. They could phone me, they could email me, something, but nothing of the sort happened. Suspend without Prejudice. Thats the best way to get the customer’s attention!

Now, not only could I not make calls and sms’s, I could not receive calls or sms’s. Further, I could not even call MTN’s toll free phone number. I had to use someone else’s phone to get to the bottom of the problem. After two days of haggling I finally found a lady kind enough to re-enable the account. Ten days later my salary goes in, I call the same number and hear a number close toR900”. I think to myself maybe I should double-check juuuust in case I mis-heard. I call again, I hear the same number again. Right. Pay the R900. Fifteen days later, my phone is suspended AGAIN. WTH?

Remember what I mentioned earlier?: “this amount was ne the amount owing on the account but the last amount that was billed.” So, in spite of the fact that the voice prompt specifically saysPress 3 for Balance Due; [Presses 3] ; The Total Outstanding Balance is; Nine; hundred; in; #whatever ; Rands; in; #whatever; cents”, I actually owed them R900 plus the R400 that I’d paid short the previous month. No, I do not know if MTN has fixed this. I no longer care. Since I figured this out I started waiting for paper statements to see how much was actually due. Interestingly, their paper statements were also wrong. Only they had the opposite problem: “This invoice: R1300in spite of the fact that on the next page it says opening balanceR400”, closing balanceR1300”. Pah! Is it fixed? Again, I don’t care.

I let them know I wasn’t renewing the contract and I’ve now already ported my number away to Virgin Mobile. Because I want to keep my number and port it elsewhere, the store said I could not putunsatisfactory serviceas the reason for ending the contract but that it should simply sayporting”. Apparently by putting anything else there they might notnoticethat I want it ported. WTF.

What next? (without MTN)

In my research I’ve found that contractdealsare most popular. Typically, you can get a R8000 phone for R800 per month over 24 months with R500-odd worth of airtime per month. This amounts to you paying R19 200 over a 24-month period for a phone worth R8000 which will be obsolete within 12 mesecev. You will get some airtime every month so you might feel its not a complete loss. However you should also remember that it costs the cellular companies nothing when you make those phone calls. Dobiček.

There’s a better way

There are much cheaper contracts, contracts for between R50 and R200 which include cheapish phonesphones that work damned well as a phone but won’t let you play games on the train. Most of these contracts actually give you the same airtime value (sometimes more!) as what you are paying. So for R100 you might get R100 worth of airtime plus some free sms’s, and a cheapish phone. The best deals I’ve seen recently have all been for the Samsung STAR, an understated but good cell phone, available from a number of retailers for between R100 and R200 per month. In most cases the deals have included the full amount of airtime. Virgin Mobile has probably the best example here: The cost is R199 per month which includes R200 in airtime and 1000 sms’s (ja, you read that rightone thousand!).

Virginal Service All the Way!

Another reason I’ve gone with Virgin Mobile is a little something no other service provider does: AmixedContract/Prepaid facility. I get R200 in airtime however, if I go over that, the extra just gets added to my invoice. With MTN this could go sky high without the option of a limit! With Virgin, because I asked, it has a limit of R300. Vendar, I can still add prepaid airtime (with cellphone banking, nogal). No other service provider lets you do this!

Remember that R8000 cell phone I mentioned earlier? My plan is to get the Samsung STAR and spend less than R300 per month. I’ll have saved enough money to actually go and buy a more expensive phone (or laptop) with the cash I’ll have saved! Seveda, if you actually use that R800-worth of phone calls, I guess the best available deal is where you spend the R19200 anyway. Maybe at least with a more critical view on your choices you’ll save yourself a good amount of money in future. Good luck in your search for your best deal!

delež
Thursday, November 12th, 2009 | Avtor:

If you ever find yourself updating a single application in Arch Linux (a very bad idea, btw) and it upgrades readline you might end up seeing an error along the lines of:
/bin/bash: error while loading shared libraries: libreadline.so.5: cannot open shared object file: No such file or directory
Hopefully you still have a bash prompt open and you haven’t closed them all. If you still can, immediately run the following:
pacman -S bash
else you won’t be able to run bash any more because bash would still be linking to the old version of readline.

tudi, in future, don’t run
pacman -Sy application
(python in my case)
instead, run:
pacman -Syu
which will ensure that all applications are upgraded.

Personally, I think that bash should have had a dependency set saying that it required the old specific version of readline and the same for the new bash, requiring the new version of readline. Regardless, rather play it safe. 😉

delež