Archive for the Category » computing «

Sunday, August 04th, 2013 | Author:

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.

Mar sin féin, 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” nó “man fsck”, you have to inputfsck.ext4help” nó “man fsck.ext4”. 🙂

Comhroinn
Sunday, August 04th, 2013 | Author:

Stair

Bhí athrú i bhfad ó luaigh mé mo deireanach freastalaí pearsanta – tá sé tar éis fás ag Raidió Rí Rá (Tá sé anois ina 7TB md RAID6) agus bhí sé atógadh le déanaí le Ubuntu Freastalaí.

Arch Ní raibh botún. Arch Linux bhí múinte cheana féin dom an oiread sin faoi Linux (agus leanfaidh sé sin a dhéanamh ar mo dheasc eile). Ach Éilíonn Arch cinnte níos mó ama agus aird ná mar ba mhaith liom a chaitheamh ar fhreastalaí. Go hidéalach, ba mhaith liom is fearr a bheith in ann a dearmad a dhéanamh ar an bhfreastalaí ar feadh tamaill go dtí go deir r-phost meabhrúcháin “tamall de bhlianta anuas … níl nuashonruithe cúpla ba chóir duit féachaint ar, buddy.”

Níl spás saor in aisce – agus nách spás

Bhí an deis dul ar imirce chun Ubuntu an bhfíric go raibh rith mé amach as SATA calafoirt, na calafoirt is gá chun thiomáineann crua a nascadh leis an gcuid eile den ríomhaire – Úsáideann an sraith Raid 7TB a lán de na calafoirt! Bhí mé fiú a tugadh ar shiúl mo an- sean dhiosca crua 200GB mar a thóg sé suas ar cheann de na calafoirt. Rabhadh mé freisin an faighteoir go bhfuil an diosca ar SMART monatóireachta le fios go raibh sé neamhiontaofa. Mar workaround sealadach chun an easpa calafoirt SATA, Bhí mé aistríodh fiú OS an fhreastalaí le sraith de cheithre bataí USB i md RAID1. Crazy. Tá a fhios agam. Ní raibh mé ró-sásta mar gheall ar an luas. Bheartaigh mé dul amach agus a cheannach tiomáint crua iontaofa nua agus cárta leathnú SATA chun dul leis é.

Cuireadh laindéal bunscoile Arch an fhreastalaí a úsáideann thart ar 7GB de diosca. A smután mór de go raibh babhtála comhad, sonraí i dtaisce agus comhaid ilghnéitheacha eile nó nach bhfuil gá. Tríd is tríd an méid iarbhír an OS, lena n-áirítear an /baile fillteán, raibh ach thart ar 2GB. Spreag sé seo dom chun breathnú isteach i Super-tapa SSD tiomáint, ag smaoineamh b'fhéidir nach mbeadh ceann níos lú a bheith chomh costasach. Iompaigh sé amach go bhfuil an feachtas saoire neamh-SSD raibh mé in ann teacht ar iarbhír costas níos mó mó ná ceann amháin de na SSDs réasúnta beag. Yay for me. 🙂

Rogha? Woah?!

I roghnú an OS, Ba mhaith chinn mé cheana féin nach mbeadh sé Arch. Lasmuigh de na dáiltí eile tóir, Tá mé an chuid is mó eolas maidir leis Ubuntu agus CentOS. Fedora Bhí freisin an deis ann – ach ní raibh a mheas mé dáiríre fós é ar feadh freastalaí. Bhuaigh an babhta ubuntu.

An cinneadh eile a bhí mé a dhéanamh nach raibh a tharlaíonn go dom go dtí go Ubiquity (Draoi suiteála Ubuntu ar) D'iarr sé orm: Conas a chur ar bun ar an Deighiltí.

Bhí mé nua chun úsáid a bhaint as SSDs i Linux – Tá mé go maith an eolas faoi na pitfalls de nach n-úsáideann iad i gceart, den chuid is mó mar gheall ar a riosca fadsaoil bochta má mí-úsáid.

Ní raibh mé ag iarraidh úsáid a bhaint as dheighilt babhtála tiomnaithe. Plean mé ar uasghrádú an fhreastalaí motherboard / LAP / cuimhne nach bhfuil i bhfad ró-sa todhchaí. Bunaithe ar sin chinn mé go mbeidh mé babhtála i gcomhad babhtála ar an Raid md atá ann cheana féin. Ní bheidh an babhtála a bheith go háirithe go tapa ach beidh a chuspóir amháin a bheith le haghaidh an ócáid ​​annamh nuair atá rud éigin mícheart agus nach bhfuil an chuimhne atá ar fáil.

D'fhág mé ansin a thabhairt ar an cosán fhréamh an 60GB iomlán amach ar Intel 330 SSD. Mheas mé a scaradh / bhaile ach an chuma air ach beagán pointless, thabhairt ar conas is beag a úsáideadh san am atá thart. Leag mé an chéad suas an laindéal le LVM – rud éigin a bhí mé le déanaí ag déanamh aon uair a leag mé suas le bosca Linux (i ndáiríre, níl aon leithscéal gan úsáid a bhaint LVM). Nuair a fuair sé an chuid i gcás ina mbeadh liom a chumrú córas comhad, Chliceáil mé ar an anuas agus instinctively roghnaithe ext4. Ansin thug mé faoi deara btrfs ar an liosta céanna. Hang on!!

Ach cad?

Btrfs (“im-eff-CSE”, “níos fearr eff-CSE”, “bee-crann-eff-CSE”, nó is cuma cad mhaisiúil tú ar an lá) tá córas comhaid sách nua a fhorbairt chun go mbeidh Linux’ cumais córas comhad ar ais ar an rian le córas comhad reatha ardteicneolaíochta. An Rí-ar-an-Hill atá ann cheana féin córas comhad, “ext” (an leagan reatha a dtugtar ext4) Is maith go leor – ach tá teorainn léi, bhfostú i paraidím d'aois (smaoineamh ar branda nua F22 Raptor vs. le F4 Phantom le iarracht leath-jested ag uasghrádú a ghlacadh) agus is dócha a bheith in ann dul san iomaíocht le haghaidh an-fhada le córais comhaid le Fiontraíocht níos nuaí mar ZFS Oracle. Btrfs Tá fós bealach fada chun dul agus meastar é fós turgnamhach (ag brath ar cé tú ceisteanna a chur agus cad iad na gnéithe is gá duit). Go leor a mheas sé a bheith cobhsaí lena n-úsáid bhunúsach – ach tá aon duine ag dul a dhéanamh ar aon ráthaíochtaí. Agus, ar ndóigh, gach duine ag rá a dhéanamh agus a thástáil cúltacaí!

Mooooooo

Is é an difríocht is bunúsaí idir fo-líne agus btrfs go bhfuil btrfs a “Bó” nó “Cóip ar Scríobh” córas comhad. Ciallaíonn sé seo go riamh go bhfuil na sonraí iarbhír overwritten d'aon ghnó ag an córas comhad ar internals. Má scríobhann tú athrú ar comhad, Beidh btrfs scríobh do chuid athruithe go dtí suíomh nua ar mheáin fhisiciúla agus beidh cothrom le dáta an leideanna inmheánacha a tharchur chuig an suíomh nua. Btrfs a théann céim eile sa mhéid is go na leideanna inmheánacha (dá dtagraítear mar meiteashonraí) Tá freisin Bó. Bheadh ​​leaganacha níos sine de fo-líne a bheith ach overwritten na sonraí. Bheadh ​​Ext4 úsáid Iris chun a chinntiú nach mbeidh éilliú tarlú ba chóir an breiseán AC a yanked amach i láthair na huaire is inopportune. Na torthaí iris i líon céanna de céimeanna a theastaíonn chun sonraí a thabhairt cothrom le dáta. Le SSD, Feidhmíonn an crua-earraí bunúsacha próiseas bó den chineál céanna is cuma cén córas comhaid tá tú ag baint úsáide as. Tá sé seo toisc nach féidir thiomáineann SSD forscríobh iarbhír sonraí – tá siad a chóipeáil na sonraí (le do chuid athruithe) go dtí suíomh nua agus ansin scriosadh an bloc sean go hiomlán. Tá leas iomlán a bhaint sa réimse seo ná nach bhféadfadh SSD scriosadh fiú an bloc d'aois ach go simplí a dhéanamh nóta a scriosadh an bloc ag tráth níos déanaí nuair nach bhfuil rudaí chomh gnóthach. Is é an toradh deiridh go cuí thiomáineann SSD go han-mhaith le córas comhaid bó agus nach bhfuil a dhéanamh chomh maith le córais comhaid le neamh-bó.

Chun a dhéanamh cúrsaí suimiúla, Bó sa chóras comhad a théann go héasca lámh ar láimh le gné ar a dtugtar deduplication. Ligeann sé seo dhá (nó níos mó) bloic comhionann le sonraí a stóráil ag baint úsáide as ach cóip amháin, spás a shábháil. Le bó, má tá an comhad mionathraithe deduplicated, Ní bheidh na focail ar leith tionchar a bheith mar beidh an comhad a mhodhnú ar shonraí a bheith scríofa bloc éagsúla fisiciúil.

Déanann bó i ndiaidh a snapshotting réasúnta éasca a chur i bhfeidhm. Nuair a pictiúr a dhéanamh taifead ar an gcóras ach an pictiúr nua a bheith ina dúbailt na sonraí agus na meiteashonraí laistigh den toirt. Le bó, nuair a dhéantar athruithe, tréimhsí an pictiúr shonraí slán, agus is féidir d'fhonn teacht ar an córas comhaid stádas ag an am a rinneadh an pictiúr a choinneáil.

A chara nua

Leis an méid sin thuas i gcuimhne, go háirithe mar tá Ubuntu ar btrfs ar fáil mar rogha shuiteáil-am, Figured mé go mbeadh sé ina am trátha chun tumadóireacht a dheanamh i btrfs agus beagán iniúchadh. 🙂

Cuid 2 ag teacht go luath …

Comhroinn
Monday, October 29th, 2012 | Author:

Is cosúil go, i n-eagna gan teorainn, Google Tá gné slándála gur féidir bloc iarratas ó rochtain a fháil nó ag baint úsáide as do chuntas google. Is féidir liom a fheiceáil conas a d'fhéadfadh sé seo a bheith ina fhadhb d'úsáideoirí Google, go háirithe a Gtalk agus Gmail úsáideoirí. I mo chás a bhí sé Nasctheanga a bhfuil i gceist leis an Jabber seirbhíse (atá go teicniúil chuid de Gtalk). Fuair ​​mé an réiteach tar éis beag tochailt. Bhí ionadh orm ar an gcaoi a aois a bhí an cheist agus cé chomh fada an ghné seo ann!

A dhíghlasáil an cuntas agus d'iarratas ar líne a fháil, bain úsáid as leathanach Captcha Google anseo.

Comhroinn
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 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 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; agus; #whatever ; Rands; agus; #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 mhí. 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. Brabús.

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 (yes, 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. Mar sin féin, 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! Ar ndóigh,, 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!

Comhroinn
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.

chomh maith leis sin, 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. 😉

Comhroinn