diff --git a/AUTHORS b/AUTHORS new file mode 100644 index 00000000..beee772a --- /dev/null +++ b/AUTHORS @@ -0,0 +1,7 @@ +Main responsible developer: Thomas Schoebel-Theuer (tst@1und1.de) + +Some scripts / testing / docs are from Joerg Mann (freelancer at 1&1) +and from Ulrich Goettlich / Ingvar Gilbert (sysadmins). + +Further thanks go to many people inside 1&1 who protected and promoted +MARS, influenced my goals and strategies, and gave me the time to do it. diff --git a/COPYING b/COPYING new file mode 100644 index 00000000..d159169d --- /dev/null +++ b/COPYING @@ -0,0 +1,339 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) year name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. diff --git a/ChangeLog b/ChangeLog new file mode 100644 index 00000000..e5a2e3de --- /dev/null +++ b/ChangeLog @@ -0,0 +1 @@ +See git history in https://github.com/schoebel/mars/commits/master diff --git a/INSTALL b/INSTALL new file mode 100644 index 00000000..4dbcc158 --- /dev/null +++ b/INSTALL @@ -0,0 +1,84 @@ +Go to your linux source tree, and apply one of the pre-patches for MARS. +You can find them in the subdirectory pre-patches/ of the MARS sources. + +These pre-patches are almost trivial, they contain only a few +EXPORT_SYMBOL() statements. Porting to other kernel versions should +be trivial. If not, please report a bug :) + +One of the pre-patches has been ported to an openvz kernel +even by one of our sysadmins, who usually does no C programming. +So this should be no major hurdle. + +Because of the need for some small pre-patches, there is currently +no infrastructure for builing MARS seaparately as standalone kernel module. +Currently, you have to compile it inplace in your kernel source tree. + +Go to ${your_kernel_source}/block/ and clone the MARS git repository there. + +Then build your kernel as usual. + +In Kconfig, you will find lots of additional options for MARS. Most +of them should be left at their default. It suffices just to switch +on MARS as a whole, and let it build as a single kernel module. + +Finally, copy userspace/marsadm to some appropriate location in +your $PATH. + +Do the following at both your primary and secondary node: + +After booting your pre-patched kernel, don't modprobe mars. Before +that, create an empty filesystem with at least 100GB (currently +ext3 recommended; there seem to remain some recursion deadlock problems +with xfs which will be hopefully fixed in the next time) +and mount it to /mars/ . + +Additionally, you need an empty block device having exactly the same +size at both nodes. In the following, they are called /dev/vg-x/myspace . + +On the primary: + marsadm create-cluster + +On the secondary: + marsadm join-cluster ${hostname_of_primary} + +Only after that, do on both nodes: + modprobe mars + +On the primary: + marsadm create-resource myspace /dev/vg-x/myspace + +Wait a few seconds until the state information about the new resource has +spread over the whole cluster. + +On the secondary: + marsadm join-resource myspace /dev/vg-x/myspace + +Shortly after that, the initial full sync should start automatically. +On the primary, a device /dev/mars/myspace should appear, having exactly +the same size as /dev/vg-x/myspace . + +Now you can use /dev/mars/myspace on the primary for creating a filesystem, +mounting, or exporting via iSCSI, etc. + +From time to time, you should execute the following commands on one of +your nodes: + marsadm log-rotate all + sleep 10 + marsadm log-delete-all all +... in order to prevent your /mars/ filesystem from running full. + +hint: use cron jobs for automation. + +Most marsadm commands are very similar to drbdadm. A better documentation +should appear in the next months. The sourcecode of marsadm is a very +simple and stupid perl script, which intentionally does not use any +perl module and no OO. The source code will tell you almost anything +about the symlinks present in /mars/ until there is better documentation. + +If you are curious about how MARS replicates its state information +over the network, just do the following on both nodes: + watch ls -l /mars/resource-myspace/ + +Alternatively / additionally, you may try Joerg's script mars-status.pl +which will deliver colorful state reports from the practical viewpoint +of an experienced sysadmin. diff --git a/NEWS b/NEWS new file mode 100644 index 00000000..ba9077f9 --- /dev/null +++ b/NEWS @@ -0,0 +1 @@ +see https://github.com/schoebel/mars diff --git a/README b/README new file mode 100644 index 00000000..c1244308 --- /dev/null +++ b/README @@ -0,0 +1,68 @@ +GPLed software AS IS, sponsored by 1&1 Internet AG (www.1und1.de). + +MARS Light is almost a drop-in replacement for DRBD +(that is, block-level storage replication). + +In contrast to plain DRBD, it works _asynchronously_ and over +arbitrary distances. + +WARNING! Current stage is BETA. Don't put productive data on it! + +Documentation: currently very rudimentary, some even in German. +This will be fixed soon. + +Concepts: + +There is a 2-years old concept paper in German which is so much outdated, +that I don't want to publish it. Please be patient until I write a +comprehensive paper at the concept level in English. + +For the meantime, please look at my presentation about MARS at LCA2013 +(linux.conf.au). + +History: + +As you can see in the git log, it evolved from a very experimental +concept study, starting in the Summer of 2010. +At this time, I was working on it in my spare time. + +In Summer 2011, an "official" internal 1&1 project started, which aimed +to deliver a proof of concept. +In February 2012, a pilot system was rolled out to an internal statistics +server, which collects statistics data from thousands of other servers, +and thus produces a very heavy random-access write load, formerly +replicated with DRBD (which led to performance problems due to massive +randomness). After switching to MARS, the performance was provably +better. +This server was selected because potential loss of statistics data +would be not be that critical as with other productive data, but +nevertheless it operates on productive data and loads. + +After curing some small infancy problems, this server runs until today +(end of January 2013) without problems. Our sysadmins even switched the +primary side a few times, without informing me, so I could +sleep better at night without knowing what they did ;) + +In Summer 2012, the next "official" internal 1&1 project started. Its goal +is to reach enterprise grade, and therefore to rollout MARS Light on +~10 productive servers, starting with less critical systems like ones +for test webspaces etc. This project will continue until Summer 2013. + +Hopefully, there will be a followup project for mass rollout to some +thousands of servers. + +In December 2012 (shortly before Christmas), I got the official permission +from our CTO Henning Kettler to publish MARS under GPL on github. + +Many thanks to him! + +Before that point, I was bound to my working contract which keeps internal +software as secret by default (when there is no explicit permission). + +Now there is a chance to build up an opensource +community for MARS, partially outside of 1&1. + +Please contribute! I will be open. + +I also try to respect the guidelines from Linus, but probably this +will need more work. Help is always welcome!