X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/d00856cc47cd2a9e90b298b284988fe623f24269..b6b6575e368fa0e8d3ac34a3a09aa1e21132be0e:/blog/index.rss diff --git a/blog/index.rss b/blog/index.rss index 94283c83ef..6f8847277d 100644 --- a/blog/index.rss +++ b/blog/index.rss @@ -6,6 +6,125 @@ http://people.skolelinux.org/pere/blog/ + + Some notes on fault tolerant storage systems + http://people.skolelinux.org/pere/blog/Some_notes_on_fault_tolerant_storage_systems.html + http://people.skolelinux.org/pere/blog/Some_notes_on_fault_tolerant_storage_systems.html + Wed, 1 Nov 2017 15:35:00 +0100 + <p>If you care about how fault tolerant your storage is, you might +find these articles and papers interesting. They have formed how I +think of when designing a storage system.</p> + +<ul> + +<li>USENIX :login; <a +href="https://www.usenix.org/publications/login/summer2017/ganesan">Redundancy +Does Not Imply Fault Tolerance. Analysis of Distributed Storage +Reactions to Single Errors and Corruptions</a> by Aishwarya Ganesan, +Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, and Remzi +H. Arpaci-Dusseau</li> + +<li>ZDNet +<a href="http://www.zdnet.com/article/why-raid-5-stops-working-in-2009/">Why +RAID 5 stops working in 2009</a> by Robin Harris</li> + +<li>ZDNet +<a href="http://www.zdnet.com/article/why-raid-6-stops-working-in-2019/">Why +RAID 6 stops working in 2019</a> by Robin Harris</li> + +<li>USENIX FAST'07 +<a href="http://research.google.com/archive/disk_failures.pdf">Failure +Trends in a Large Disk Drive Population</a> by Eduardo Pinheiro, +Wolf-Dietrich Weber and Luiz André Barroso</li> + +<li>USENIX ;login: <a +href="https://www.usenix.org/system/files/login/articles/hughes12-04.pdf">Data +Integrity. Finding Truth in a World of Guesses and Lies</a> by Doug +Hughes</li> + +<li>USENIX FAST'08 +<a href="https://www.usenix.org/events/fast08/tech/full_papers/bairavasundaram/bairavasundaram_html/">An +cAnalysis of Data Corruption in the Storage Stack</a> by +L. N. Bairavasundaram, G. R. Goodson, B. Schroeder, A. C. +Arpaci-Dusseau, and R. H. Arpaci-Dusseau</li> + +<li>USENIX FAST'07 <a +href="https://www.usenix.org/legacy/events/fast07/tech/schroeder/schroeder_html/">Disk +failures in the real world: what does an MTTF of 1,000,000 hours mean +to you?</a> by B. Schroeder and G. A. Gibson.</li> + +<li>USENIX ;login: <a +href="https://www.usenix.org/events/fast08/tech/full_papers/jiang/jiang_html/">Are +Disks the Dominant Contributor for Storage Failures? A Comprehensive +Study of Storage Subsystem Failure Characteristics</a> by Weihang +Jiang, Chongfeng Hu, Yuanyuan Zhou, and Arkady Kanevsky</li> + +<li>SIGMETRICS 2007 +<a href="http://research.cs.wisc.edu/adsl/Publications/latent-sigmetrics07.pdf">An +analysis of latent sector errors in disk drives</a> by +L. N. Bairavasundaram, G. R. Goodson, S. Pasupathy, and J. Schindler</li> + +</ul> + +<p>Several of these research papers are based on data collected from +hundred thousands or millions of disk, and their findings are eye +opening. The short story is simply do not implicitly trust RAID or +redundant storage systems. Details matter. And unfortunately there +are few options on Linux addressing all the identified issues. Both +ZFS and Btrfs are doing a fairly good job, but have legal and +practical issues on their own. I wonder how cluster file systems like +Ceph do in this regard. After, all the old saying, you know you have +a distributed system when the crash of a compyter you have never heard +of stops you from getting any work done. The same holds true if fault +tolerance do not work.</p> + +<p>Just remember, in the end, it do not matter how redundant, or how +fault tolerant your storage is, if you do not continuously monitor its +status to detect and replace failed disks.</p> + + + + + Web services for writing academic LaTeX papers as a team + http://people.skolelinux.org/pere/blog/Web_services_for_writing_academic_LaTeX_papers_as_a_team.html + http://people.skolelinux.org/pere/blog/Web_services_for_writing_academic_LaTeX_papers_as_a_team.html + Tue, 31 Oct 2017 21:00:00 +0100 + <p>I was surprised today to learn that a friend in academia did not +know there are easily available web services available for writing +LaTeX documents as a team. I thought it was common knowledge, but to +make sure at least my readers are aware of it, I would like to mention +these useful services for writing LaTeX documents. Some of them even +provide a WYSIWYG editor to ease writing even further.</p> + +<p>There are two commercial services available, +<a href="https://sharelatex.com">ShareLaTeX</a> and +<a href="https://overleaf.com">Overleaf</a>. They are very easy to +use. Just start a new document, select which publisher to write for +(ie which LaTeX style to use), and start writing. Note, these two +have announced their intention to join forces, so soon it will only be +one joint service. I've used both for different documents, and they +work just fine. While +<a href="https://github.com/sharelatex/sharelatex">ShareLaTeX is free +software</a>, while the latter is not. According to <a +href="https://www.overleaf.com/help/17-is-overleaf-open-source">a +announcement from Overleaf</a>, they plan to keep the ShareLaTeX code +base maintained as free software.</p> + +But these two are not the only alternatives. +<a href="https://app.fiduswriter.org/">Fidus Writer</a> is another free +software solution with <a href="https://github.com/fiduswriter">the +source available on github</a>. I have not used it myself. Several +others can be found on the nice +<a href="https://alternativeto.net/software/sharelatex/">alterntiveTo +web service</a>. + +<p>If you like Google Docs or Etherpad, but would like to write +documents in LaTeX, you should check out these services. You can even +host your own, if you want to. :)</p> + + + + Locating IMDB IDs of movies in the Internet Archive using Wikidata http://people.skolelinux.org/pere/blog/Locating_IMDB_IDs_of_movies_in_the_Internet_Archive_using_Wikidata.html @@ -82,7 +201,7 @@ automatically.</p> and check if the XML metadata for the movie is available from The Internet Archive, and after around 1.5 hour it produced a list of 2097 free movies and their IMDB ID. In total, 171 entries in Wikidata lack -the refered Internet Archive entry. I assume the 60 "disappearing" +the refered Internet Archive entry. I assume the 70 "disappearing" entries (ie 2338-2097-171) are duplicate entries.</p> <p>This is not too bad, given that The Internet Archive report to @@ -655,82 +774,5 @@ one frequency?</p> - - Norwegian Bokmål edition of Debian Administrator's Handbook is now available - http://people.skolelinux.org/pere/blog/Norwegian_Bokm_l_edition_of_Debian_Administrator_s_Handbook_is_now_available.html - http://people.skolelinux.org/pere/blog/Norwegian_Bokm_l_edition_of_Debian_Administrator_s_Handbook_is_now_available.html - Tue, 25 Jul 2017 21:10:00 +0200 - <p align="center"><img align="center" src="http://people.skolelinux.org/pere/blog/images/2017-07-25-debian-handbook-nb-testprint.png"/></p> - -<p>I finally received a copy of the Norwegian Bokmål edition of -"<a href="https://debian-handbook.info/">The Debian Administrator's -Handbook</a>". This test copy arrived in the mail a few days ago, and -I am very happy to hold the result in my hand. We spent around one and a half year translating it. This paperbook edition -<a href="https://debian-handbook.info/get/#norwegian">is available -from lulu.com</a>. If you buy it quickly, you save 25% on the list -price. The book is also available for download in electronic form as -PDF, EPUB and Mobipocket, as can be -<a href="https://debian-handbook.info/browse/nb-NO/stable/">read online -as a web page</a>.</p> - -<p>This is the second book I publish (the first was the book -"<a href="http://free-culture.cc/">Free Culture</a>" by Lawrence Lessig -in -<a href="http://www.lulu.com/shop/lawrence-lessig/free-culture/paperback/product-22440520.html">English</a>, -<a href="http://www.lulu.com/shop/lawrence-lessig/culture-libre/paperback/product-22645082.html">French</a> -and -<a href="http://www.lulu.com/shop/lawrence-lessig/fri-kultur/paperback/product-22441576.html">Norwegian -Bokmål</a>), and I am very excited to finally wrap up this -project. I hope -"<a href="http://www.lulu.com/shop/rapha%C3%ABl-hertzog-and-roland-mas/h%C3%A5ndbok-for-debian-administratoren/paperback/product-23262290.html">Håndbok -for Debian-administratoren</a>" will be well received.</p> - - - - - «Rapporten ser ikke på informasjonssikkerhet knyttet til personlig integritet» - http://people.skolelinux.org/pere/blog/_Rapporten_ser_ikke_p__informasjonssikkerhet_knyttet_til_personlig_integritet_.html - http://people.skolelinux.org/pere/blog/_Rapporten_ser_ikke_p__informasjonssikkerhet_knyttet_til_personlig_integritet_.html - Tue, 27 Jun 2017 17:50:00 +0200 - <p>Jeg kom over teksten -«<a href="https://freedom-to-tinker.com/2017/06/21/killing-car-privacy-by-federal-mandate/">Killing -car privacy by federal mandate</a>» av Leonid Reyzin på Freedom to -Tinker i dag, og det gleder meg å se en god gjennomgang om hvorfor det -er et urimelig inngrep i privatsfæren å la alle biler kringkaste sin -posisjon og bevegelse via radio. Det omtalte forslaget basert på -Dedicated Short Range Communication (DSRC) kalles Basic Safety Message -(BSM) i USA og Cooperative Awareness Message (CAM) i Europa, og det -norske Vegvesenet er en av de som ser ut til å kunne tenke seg å -pålegge alle biler å fjerne nok en bit av innbyggernes privatsfære. -Anbefaler alle å lese det som står der. - -<p>Mens jeg tittet litt på DSRC på biler i Norge kom jeg over et sitat -jeg synes er illustrativt for hvordan det offentlige Norge håndterer -problemstillinger rundt innbyggernes privatsfære i SINTEF-rapporten -«<a href="https://www.sintef.no/publikasjoner/publikasjon/Download/?pubid=SINTEF+A23933">Informasjonssikkerhet -i AutoPASS-brikker</a>» av Trond Foss:</p> - -<p><blockquote> -«Rapporten ser ikke på informasjonssikkerhet knyttet til personlig - integritet.» -</blockquote></p> - -<p>Så enkelt kan det tydeligvis gjøres når en vurderer -informasjonssikkerheten. Det holder vel at folkene på toppen kan si -at «Personvernet er ivaretatt», som jo er den populære intetsigende -frasen som gjør at mange tror enkeltindividers integritet tas vare på. -Sitatet fikk meg til å undres på hvor ofte samme tilnærming, å bare se -bort fra behovet for personlig itegritet, blir valgt når en velger å -legge til rette for nok et inngrep i privatsfæren til personer i -Norge. Det er jo sjelden det får reaksjoner. Historien om -reaksjonene på Helse Sør-Østs tjenesteutsetting er jo sørgelig nok et -unntak og toppen av isfjellet, desverre. Tror jeg fortsatt takker nei -til både AutoPASS og holder meg så langt unna det norske helsevesenet -som jeg kan, inntil de har demonstrert og dokumentert at de verdsetter -individets privatsfære og personlige integritet høyere enn kortsiktig -gevist og samfunnsnytte.</p> - - -