Archive for the Category » computing «

Sunday, August 04th, 2013 | Author:

I had a power outage affect my server’s large MD ATAK 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.

Sepandan, 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” oswa “man fsck”, you have to inputfsck.ext4help” oswa “man fsck.ext4”. 🙂

pataje
Sunday, August 04th, 2013 | Author:

Istwa

Anpil te chanje depi dènye mansyone mwen pèsonèl sèvè – li te grandi pa leaps ak limit (li kounye a gen yon 7TB MD RAID6) epi li te dènyèman te rebati ak Ubuntu Sèvè.

Arch pa te janm yon erè. Arch Linux te deja te moutre m 'anpil sou Linux (epi yo pral kontinye fè sa sou Desktop lòt m '). Men, Arch definitivman mande pou plis tan ak atansyon pase Mwen ta renmen pase sou yon sèvè. Idealman mwen ta pito pou kapab bliye sou sèvè a pou yon ti tan jiskaske yon imel rapèl di “um … gen yon dènye koup ou ta dwe gade nan, zanmi.”

Espas se pa gratis – ak ni se pa espas

Opòtinite nan emigre nan Ubuntu te lefèt ke mwen te kouri soti nan Sata pò, pò yo oblije konekte kondui difisil yo rès la nan òdinatè a – ki etalaj ATAK 7TB sèvi ak yon anpil nan pò! Mwen te menm ki te fè kado mwen trè fin vye granmoun 200GB ki gen kapasite difisil kòm li te pran moute youn nan moun ki pò. Mwen menm mwen te avèti moun k ap resevwa a ki gen kapasite a SMART siveyans endike li te enfidèl. Kòm yon solisyon tanporè nan mank nan pò sata, Mwen te menm te imigre eksplwatasyon sèvè a nan yon seri kat baton USB nan yon MD RAID1. Fou. Mwen konnen. Mwen pa t 'twò kontan sou vitès la. Mwen deside ale deyò epi yo achte yon nouvo serye kondwi difisil ak yon kat ekspansyon sata yo ale ak li.

Prensipal patisyon sèvè a nan Arch te lè l sèvi avèk sou 7GB nan ki gen kapasite. Yon moso gwo nan sa ki te yon swap dosye, done kach ak otreman divès oswa nesesè dosye. An tou gwosè aktyèl la nan eksplwatasyon an, ki gen ladan an /lakay katab, te sèlman sou 2GB. Sa a pouse m 'nan gade nan yon super vit- SSD kondwi, panse petèt yon yon sèl ki pi piti yo pa ta ka tèlman chè. Li te tounen soti ke pi bon mache ki pa SSD kondwi a mwen te kapab jwenn aktyèlman koute plis pase youn nan sa yo SSDs relativman ti. Ye pou m '. 🙂

Chwa? Wa?!

Lè w ap chwazi eksplwatasyon an, Mwen ta deja deside li pa ta dwe Arch. Soti nan tout distribisyon yo ak lòt popilè, Mwen se pi abitye ak Ubuntu ak CentOS. Fedora te tou yon posibilite – men mwen pa t 'seryezman ankò konsidere li pou yon sèvè. Ubuntu te genyen tou nan.

Desizyon nan pwochen mwen te fè pa t 'rive jwenn mwen an rive Ubikwite (Sòsye enstalasyon ubentu a) mande li nan m ': Kouman yo mete a moute Partitions.

Mwen te nouvo nan lè l sèvi avèk SSDs nan Linux – Mwen byen okouran de Handbuch yo nan pa sèvi avèk yo kòrèkteman, sitou akòz risk yo nan lonjevite pòv si abusive.

Mwen pa t 'vle sèvi ak yon patisyon swap devwe. Mwen plan sou mete ajou mèr sèvè a / CPU / memwa pa twò lwen nan lavni an. Ki baze sou ki mwen deside mwen pral mete swap nan yon dosye swap sou atak la MD ki deja egziste. Swap a pa pral patikilyèman vit, men objektif sèlman li yo pral pou sa okazyon ra lè yon bagay nan ale mal ak memwa a pa disponib.

Sa a Lè sa a, kite m 'bay la chemen rasin 60GB a plen soti nan yon Intel 330 SSD. Mwen konsidere separe / kay, men li jis te sanble yon ti kras initil, bay ki jan ti kras te itilize nan tan lontan an. M 'premye mete kanpe patisyon an ak Lvm – yon bagay mwen te dènyèman te fè lè mwen mete kanpe yon bwat Linux (vrèman, gen nan pa gen eskiz pa sèvi ak lvm). Lè li te rive nan pati a kote mwen ta konfigirasyon filèsistèm a, Mwen klike drop-desann epi enstenktivman chwazi ext4. Lè sa a, mwen remake btrfs nan lis la menm. Kwoke sou!!

Men, yon sa?

Btrfs (“bè-efe-ESS”, “pi bon-efe-ESS”, “myèl-pyebwa-efe-ESS”, oswa kèlkeswa sa ou imajine nan jou a) se yon relativman nouvo filèsistèm devlope yo nan lòd pote Linux’ kapasite filèsistèm retounen sou track ak teknoloji aktyèl filèsistèm. Wa a-of-a-Hill ki deja egziste filèsistèm, “ext” (vèsyon aktyèl la rele ext4) se trè bon – men li se sèlman, kole nan yon paradigm fin vye granmoun (panse a yon mak nouvo F22 raptor vs. yon F4 Phantom ak yon tantativ mwatye jwe li t'ap jwe nan yon ajou ekivalans) ak se fasil yo dwe kapab fè konpetisyon pou trè long ak plus filèsistèm Enterprise tankou ZFS Oracle a. Btrfs toujou gen yon fason lontan yo ale epi li se toujou konsidere kòm eksperimantal (depann sou ki moun ou mande ak sa ki karakteristik ou bezwen). Anpil konsidere li yo dwe ki estab pou itilize de baz – men pa gen moun ki pral fè okenn garanti. Ak, nan kou, tout moun ap di yo fè ak teste sovgad!

Mooooooo

Diferans ki pi fondamantal ant ext ak btrfs se ke btrfs se yon “Bèf” oswa “Kopi sou Ekri” filèsistèm. Sa vle di ke done se pa janm aktyèlman fè espre efase pa entèrn filèsistèm a. Si ou ekri yon chanjman nan yon dosye, btrfs pral ekri chanjman ou a nan yon kote nouvo sou medya fizik epi yo pral mete pwent yo entèn, al gade nan kote a nouvo. Btrfs ale yon etap pi lwen nan ke moun endikasyon entèn (refere yo kòm Metadata) yo se tou Bèf. Vèsyon ki pi ansyen nan ext ta gen tou senpleman efase done yo. Ext4 ta sèvi ak yon Journal asire ke koripsyon pa pral rive yo ta dwe ploge nan AC yanked soti nan moman sa a ki pi inoportun. Rezilta yo jounal nan yon nimewo ki sanble nan etap oblije mete ajou done. Avèk yon SSD, pyès ki nan konpitè ki kache opere yon pwosesis bèf ki sanble pa gen pwoblèm sa filèsistèm w ap itilize. Sa a se paske SSD kondui pa ka aktyèlman recouvrir done – yo gen a kapab bay kopi done yo (ak chanjman ou) nan yon kote ak nouvo Lè sa a, efase blòk la fin vye granmoun antyèman. Yon optimize nan zòn sa a se ke yon SSD ka pa menm efase blòk la fin vye granmoun men pito tou senpleman fè yon nòt ou efase blòk la nan yon moman pita lè bagay sa yo yo pa konsa pou sa okipe. Rezilta a fen se ke kondui SSD anfòm trè byen ak yon filèsistèm bèf epi yo pa fè kòm byen ak ki pa bèf filèsistèm.

Pou fè zafè enteresan, Bèf nan filèsistèm a fasil ale men nan men ak yon karakteristik rele deduplikasyon. Sa a pèmèt de (oswa plis) blòk ki idantik nan done yo dwe estoke lè l sèvi avèk sèlman yon kopi sèl, ekonomize espas. Avèk bèf, si se yon dosye deduplicated modifye, jimo a apa pa pral afekte kòm done dosye a modifye a pral yo te ekri nan yon blòk diferan fizik.

Bèf nan vire fè snapshotting relativman fasil a aplike. Lè yo bay yon snapshot te fè sistèm nan senpleman anrejistre snapshot nan nouvo tankou se te yon repetisyon nan tout done ak Metadata nan volim nan. Avèk bèf, lè chanjman yo te fè, done snapshot an rete entak, epi li ka yon View ki konsistan de estati filèsistèm a nan lè yo te snapshot a te fè yo ap konsève a.

Yon zanmi nouvo

Avèk pi wo a nan nan tèt ou, espesyalman kòm ubentu te fè btrfs disponib kòm yon opsyon enstale-fwa, Mwen kalkile li ta yon bon moman yo plonje nan btrfs ak eksplore yon ti kras. 🙂

Pati 2 vini byento …

pataje
Monday, October 29th, 2012 | Author:

Li parèt ke, nan enfini bon konprann, Google gen yon karakteristik sekirite ki ka bloke yon aplikasyon soti nan rantre nan oswa lè l sèvi avèk kont Google ou. Mwen ka wè ki jan sa a ta kapab yon pwoblèm pou itilizatè Google la, an patikilye yo Gtolk ak Gmail itilizatè. Nan ka mwen an li te Pidjin gen yon pwoblèm ki gen nan Jabber sèvis (ki se teknikman yon pati nan gtolk). Mwen te jwenn solisyon an apre yon ti kras fouye. Mwen te etone nan ki laj kesyon an se te, ak konbyen tan sa a te karakteristik te egziste!

Déblotché kont lan epi pou yo jwenn sou entènèt aplikasyon ou lan, itilize Captcha paj Google la isit la.

pataje
Thursday, June 03rd, 2010 | Author:

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 pa 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 pa 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; ak; #whatever ; Rands; ak; #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 mwa. 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. Pwofi.

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 (repons lan se wi, 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. Sepandan, 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! Natirèlman, 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!

pataje
Thursday, November 12th, 2009 | Author:

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.

Epitou, 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. 😉

pataje