Kaydso Qeybta » xisaabinta «

Axad, Ogosto 04th, 2013 | Qoraa:

Waxaan lahaa cilad koronto oo saameyn ku yeelatay adeegeyga weyn md DUUL diyaarin. Halkii loo oggolaan lahaa in adeegu guud ahaan hoos u dhaco inta laga sugayo inuu dhammaystiro fsck, Waxaan haystay boot iyada oo aan lahayn saf ballaaran sidaa darteed waxaan ku maamuli lahaa fsck gacanta.

Si kastaba ha noqotee, markii aan gacanta ku waday waxaan ogaaday inaanan hayn wado aan ku ogaado inta ay le'eg tahay iyo muddada ay qaadanayso in la dhammaystiro. Tani waxay si gaar ah dhibaato ugu tahay noocyo badan. In yar oo aan raadinayay ayaan helay cirifka ku darida cabirka -C markii aad wacayso fsck. Tan kama aanan helin dukumiintiyada si kastaba ha ahaatee: fsck –Caawinaad ma muujin ikhtiyaar noocaas ah.

Ikhtiyaarku wuxuu noqdaa mid gaar u leh ext4, oo markaa waxay muujineysaa bar horumarineed oo si fiican u shaqeynaya oo leh tilmaame boqolkiiba. Si aad u hesho macluumaadka, halkii “fsck –I caawi” ama “nin fsck”, waa inaad ku dartaa “fsck.ext4 –I caawi” ama “nin fsck.ext4”. 🙂

Share
Axad, Ogosto 04th, 2013 | Qoraa:

Taariikhda

Inbadan ayaa isbadalay tan iyo markii ugu dambeysay ee aan sheego server shaqsiyeed – waxay ku kortay boodbooyin iyo soohdin (waxay hadda leedahay 7TB md RAID6) oo mar dhow ayaa dib loo dhisay iyadoo Ubuntu Server.

Gawaarida marna qalad ma ahayn. Arch Linux horey wax badan buu iiga baray Linux (oo waan kusii wadi doonaa inaan ku sameeyo desktop-kayga kale). Laakiin Arch xaqiiqdii waxay u baahan tahay waqti iyo feejignaan ka badan intii aan jeclaan lahaa inaan ku qaato serverka. Fikrad ahaan waxaan jeclaan lahaa inaan awoodo inaan iska iloobo adeegaha in yar illaa iimayl xusuusin ah uu dhaho “a … waxaa jira laba casriyeyn ah oo ay tahay inaad fiiriso, saaxiib.”

Meel bannaan maahan – mana aha mid bannaan

Fursadda aan ugu haajiro Ubuntu waxay ahayd xaqiiqda oo ah inaan ka dhammaaday SATA dekedaha, dekedaha loo baahan yahay inay ku xirmaan darawallada adag kombiyuutarka intiisa kale – in soo diyaarinta 7TB RAID ay isticmaasho dekedo badan! Xitaa waan bixiyay aad duug ah 200GB disk adag maadaama ay qaadatay mid ka mid ah dekedahaas. Waxaan sidoo kale uga digay qaataha in diskiga SMART kormeerku wuxuu muujiyey in aan lagu kalsoonaan karin. Sida ku-meel-gaadhka ku-meel-gaadhka ah ee la'aanta dekeddaha SATA, Xitaa waxaan u haajiray OS-ka adeegaha illaa afar xirmo oo USB ah oo ku jira md RAID1. Waali. waan ogahay. Aad uma aanan faraxsanayn xawaaraha. Waxaan go aansaday inaan baxo oo aan iibsado darawal adag oo la isku halleyn karo iyo kaarka ballaarinta SATA si aan ula socdo.

Qeybinta aasaasiga ah ee 'Arch server' waxay isticmaaleysay qiyaastii 7GB disk ah. Qeyb weyn oo ka mid ah taas ayaa ahayd a isdhaafsasho faylka, xogta keydsan iyo haddii kale faylal kaladuwan ama aan loo baahnayn. Guud ahaan cabirka dhabta ah ee OS, ay ka mid yihiin /guriga galka, wuxuu ahaa oo keliya qiyaastii 2GB. Tani waxay igu kaliftay inaan fiiriyo super-soon SSD wadid, ka fikirida mid ka yar in uusan sidaa qaali u ahayn. Waxaa ii soo baxday in kan ugu raqiisan ee aan ahayn SSD-ka ee aan runtii ku heli lahaa qiime dheeraad ah marka loo eego mid ka mid ah SSD-yadaas yar yar. Haa aniga. 🙂

Xulasho? Woah?!

Xulashada OS, Waxaan horey u go’aansaday inaysan Arch noqon doonin. Dhamaan qeybiyeyaasha kale ee caanka ah, Waxaan aad u aqaan Ubuntu iyo CentOS. Fedora sidoo kale waxay ahayd macquul – laakiin si dhab ah ugama aanan fakarin wali server. Ubuntu ayaa ku guuleysatay wareegga.

Go’aanka xiga ee aan qaadan lahaa aniga iguma soo dhicin ilaa Ubilence (Saaxir rakibaadda Ubuntu) ayaa iga weydiisay: Sida loo dejiyo xijaab.

Waxaan ku cusbaa isticmaalka SSD-ka Linux – Waxaan si fiican uga warqabaa khaladaadka jira ee aanan sida saxda ah u isticmaalin, badanaa waxay ugu wacan tahay halistooda cimri dherer xumo haddii si qaldan loo adeegsado.

Ma aanan dooneynin inaan isticmaalo qayb isku beddel ah. Waxaan qorsheynayaa kor u qaadista server-ka hooyada / CPU / Memory-ka ee aan aad ugu fogeyn mustaqbalka. Iyada oo ku saleysan taas ayaan go'aansaday inaan ku beddelanayo faylka isku-beddelka md RAID-da jirta. Isweydaarsigu si gaar ah uma noqon doono mid deg deg ah laakiin ujeedadiisa kaliya ayaa noqon doonta munaasabadaas dhifka ah marka wax khaldamaan oo xusuusta aan la helin.

Tani waxay markaa iga tagtay inaan siiyo wadada xididka 60GB buuxa ee ka mid ah Intel 330 SSD. Waxaan ka fiirsaday kala tag / guri laakiin waxay umuuqatay wax aan micno lahayn, la siiyay inta yar ee la isticmaali jiray waagii hore. Waxaan marka hore qotomiyey xijaab leh LVM – wax aan dhawaanahan sameynayay markasta oo aan dejiyo sanduuq Linux ah (run ahaantii, ma jirto wax cudurdaar ah oo aan loo isticmaalin LVM). Markay gaadhay qaybtii aan ku habayn lahaa nidaamka faylasha, Waxaan dhajiyay hoos-u-dhaca oo si xamaasad leh u xushay ext4. Kadib waxaan ku arkay btrfs isla liistada. Sudhan!!

Laakiin maxay tahay?

Btrfs (“subag-eff-ess”, “fiican-eff-ess”, “shinni-geed-eff-ess”, ama wax kastoo aad ujeceshahay maalinta) waa nidaam cusub oo faylal ah oo loo soo saaray Linux’ awoodaha faylasha ee nidaamka saxda ah ee nidaamka casriga ah. Nidaamka faylasha ee jira ee King-of-the-Hill, “dheeraad ah” (nooca hada la yiraahdo ext4) waa wax fiican – laakiin waa xaddidan tahay, ku xayiran muuqaal hore (ka fikir nooc cusub F22 Raptor vs. ah F4 Phantom oo leh isku day nus kaftan ah oo lagu hagaajinayo u dhigma) umana badna inay awood u yeelan karto inay muddo dheer la tartanto nidaamyada faylasha cusub ee Enterprise sida Oracle’s ZFS. Btrfs wali waddo dheer ayaa loo hayaa welina waxaa loo arkaa tijaabo (waxay kuxirantahay qofka aad weydiiso iyo astaamaha aad ubaahantahay). Kuwo badan waxay u tixgeliyaan inay xasilloon tahay isticmaalka aasaasiga ah – laakiin cidina ma samaynayso dammaanad qaad. Iyo, Dabcan, qof walba wuxuu dhahayaa sameyso oo tijaabiyo keyd!

Mooooooo

Farqiga ugu aasaasiga ah ee u dhexeeya ext iyo btrfs ayaa ah in btrfs-ku uu yahay a “CoW” ama “Nuqul ku qor” nidaamka faylasha. Tani waxay ka dhigan tahay in xogta aan si dhab ah si ula kac ah dib loogu qoro gudaha nidaamka faylasha. Haddii aad u qorto isbeddel feyl, btrfs waxay kuu qori doonaan isbeddeladaada meel cusub oo ku saabsan warbaahinta jirka waxayna cusbooneysiin doonaan tilmaamayaasha gudaha si ay u tixraacaan goobta cusub. Btrfs waxay tallaabo dheeri ah u qaadaysaa tilmaamayaashaas gudaha ah (loo yaqaan metadata) yihiin sidoo kale CoW. Noocyadii hore ee ext ayaa si fudud dib loogu qori lahaa xogta. Ext4 waxay isticmaali doontaa Joornaal si loo hubiyo in musuqmaasuqu uusan dhici doonin haddii fiilada AC laga siibto xilliga ugu habboon. Joornaalku wuxuu ku soo baxayaa tiro tallaabooyin la mid ah oo loo baahan yahay si loo cusbooneysiiyo xogta. Iyada oo leh SSD, qalabka hoose wuxuu ku shaqeeyaa nidaam la mid ah CoW iyadoon loo eegin nooca faylasha aad isticmaaleysid. This is because SSD drives cannot actually overwrite datathey have to copy the data (with your changes) to a new location and then erase the old block entirely. An optimisation in this area is that an SSD might not even erase the old block but rather simply make a note to erase the block at a later time when things aren’t so busy. The end result is that SSD drives fit very well with a CoW filesystem and don’t perform as well with non-CoW filesystems.

To make matters interesting, CoW in the filesystem easily goes hand in hand with a feature called deduplication. This allows two (or more) identical blocks of data to be stored using only a single copy, saving space. With CoW, if a deduplicated file is modified, the separate twin won’t be affected as the modified file’s data will have been written to a different physical block.

CoW in turn makes snapshotting relatively easy to implement. When a snapshot is made the system merely records the new snapshot as being a duplication of all data and metadata within the volume. With CoW, when changes are made, the snapshot’s data stays intact, and a consistent view of the filesystem’s status at the time the snapshot was made can be maintained.

A new friend

With the above in mind, especially as Ubuntu has made btrfs available as an install-time option, I figured it would be a good time to dive into btrfs and explore a little. 🙂

Qaybta 2 coming soon

Share
Isniinta, October 29th, 2012 | Qoraa:

It appears that, in infinite wisdom, Google have a security feature that can block an application from accessing or using your google account. I can see how this might be a problem for Google’s users, in particular their GTalk iyo Gmail users. In my case it was Pidgin having an issue with the Jabber adeegga (which is technically part of GTalk). I found the solution after a little digging. I was surprised at how old the issue was and how long this feature has existed!

To unlock the account and get your application online, use Google’s Captcha page here.

Share
Thursday, June 03rd, 2010 | Qoraa:

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 ma 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 ma 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; iyo; #whatever ; Rands; iyo; #whatever; cents”, I actually owed them R900 plus the R400 that I’d paid short the previous month. Maya, 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? Haddana, 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 months. 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. Faa'iido.

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 (haa, 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. Si kastaba ha noqotee, 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! Dabcan, 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!

Share
Thursday, November 12th, 2009 | Qoraa:

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.

Sidoo kale, 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. 😉

Share