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  • Building a new cluster for mathematical calculations (Win/Lin)

    - by Muhammad Farhan
    I would like to build a new cluster to perform heavy mathematical calculations in Matlab and Abaqus. One of my friend told me that distributed computing is way faster than parallel computing, which is very true after reading a bit on the internet. However, I have never clustered before. Current workstation I own: Dell Precision T5400 2 x Intel Xeon 2.5 GHz 16 GB RAM (2GB x 8) 1 x Western Digital 1TB HDD 7200 rpm 1 x nVidia Quadro FX4600 768MB GPU 1 x 870W PSU OS: Windows 7 Ultimate 64-bit 2nd WS: I can buy another WS similar configuration to the one I own I am not bothered about OS, I am willing to cluster with either Windows or Linux. However, my software are compatible with windows 64-bit only. Please help me setup a cluster. Thank you.

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  • mysql cluster virtual ip

    - by user225995
    I am new in mysql cluster and mysql cluster and versions are not my choice. I setup four machines. Two of them manager , Two of them data cluster (ndb and mysqld). And i integrate with mysql utilities master/slave configuration. Everything working fine. Mysql version 5.6.17, ndb 7.3.5 , servers ubuntu 14.04. There will be no much transactions. The only important thing is HA. Everythings must be double. My problem is virtual ip. Since I have only one farm which have master slave configuration, how can i do it without proxy? If I must use proxy which proxy is better?

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  • Installing DB2 in Windows 2003 Cluster

    - by radoslawc
    How can I install db2 with already created domain user? Or maybe there is no need, just install with local user db2admin and then create instance using existing domain user? This is how it looks I've got win 2003 cluster single quorum, I have to move db2 database to another cluster in same domain. I've added resources to new cluster like in IBM redbook, and I have problem adding db2 resource. I've got service account DOMAIN\serviceaccount and DOMAIN\db2_instance owner, to install db2 do I have to log in as db2_instance_owner? Thanks in advance

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  • Are there any working implementations of the rolling hash function used in the Rabin-Karp string sea

    - by c14ppy
    I'm looking to use a rolling hash function so I can take hashes of n-grams of a very large string. For example: "stackoverflow", broken up into 5 grams would be: "stack", "tacko", "ackov", "ckove", "kover", "overf", "verfl", "erflo", "rflow" This is ideal for a rolling hash function because after I calculate the first n-gram hash, the following ones are relatively cheap to calculate because I simply have to drop the first letter of the first hash and add the new last letter of the second hash. I know that in general this hash function is generated as: H = c1ak - 1 + c2ak - 2 + c3ak - 3 + ... + cka0 where a is a constant and c1,...,ck are the input characters. If you follow this link on the Rabin-Karp string search algorithm , it states that "a" is usually some large prime. I want my hashes to be stored in 32 bit integers, so how large of a prime should "a" be, such that I don't overflow my integer? Does there exist an existing implementation of this hash function somewhere that I could already use? Here is an implementation I created: public class hash2 { public int prime = 101; public int hash(String text) { int hash = 0; for(int i = 0; i < text.length(); i++) { char c = text.charAt(i); hash += c * (int) (Math.pow(prime, text.length() - 1 - i)); } return hash; } public int rollHash(int previousHash, String previousText, String currentText) { char firstChar = previousText.charAt(0); char lastChar = currentText.charAt(currentText.length() - 1); int firstCharHash = firstChar * (int) (Math.pow(prime, previousText.length() - 1)); int hash = (previousHash - firstCharHash) * prime + lastChar; return hash; } public static void main(String[] args) { hash2 hashify = new hash2(); int firstHash = hashify.hash("mydog"); System.out.println(firstHash); System.out.println(hashify.hash("ydogr")); System.out.println(hashify.rollHash(firstHash, "mydog", "ydogr")); } } I'm using 101 as my prime. Does it matter if my hashes will overflow? I think this is desirable but I'm not sure. Does this seem like the right way to go about this?

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  • How to map hash keys to methods for an encapsulated Ruby class (tableless model)?

    - by user502052
    I am using Ruby on Rails 3 and I am tryng to map a hash (key, value pairs) to an encapsulated Ruby class (tableless model) making the hash key as a class method that returns the value. In the model file I have class Users::Account #< ActiveRecord::Base def initialize(attributes = {}) @id = attributes[:id] @firstname = attributes[:firstname] @lastname = attributes[:lastname] end end def self.to_model(account) JSON.parse(account) end My hash is hash = {\"id\":2,\"firstname\":\"Name_test\",\"lastname\":\"Surname_test\"} I can make account = Users::Account.to_model(hash) that returns (debugging) --- id: 2 firstname: Name_test lastname: Surname_test That works, but if I do account.id I get this error NoMethodError in Users/accountsController#new undefined method `id' for #<Hash:0x00000104cda410> I think because <Hash:0x00000104cda410> is an hash (!) and not the class itself. Also I think that doing account = Users::Account.to_model(hash) is not the right approach. What is wrong? How can I "map" those hash keys to class methods?

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  • How do I design a cryptographic hash function?

    - by Eyal
    After reading the following about why one-way hash functions are one-way, I would like to know how to design a hash function. http://stackoverflow.com/questions/1038307/help-me-better-understand-cryptographic-hash-functions/1047106#1047106 Before everyone gets on my case: Yes, I know that it's a bad idea to not use a proven and tested hash function. I would still like to know how it's done. I'm familiar with Feistel-network ciphers but those are necessarily reversible, horrible for a cryptographic hash. Is there some sort of construction that is well-used in cryptographic hashing? Something that makes it very one-way?

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  • C++ converting hexadecimal md5 hash to decimal integer

    - by Zackery
    I'm doing Elgamal Signature Scheme and I need to use the decimal hash value from the message to compute S for signature generation. string hash = md5(message); cout << hash << endl; NTL::ZZ msgHash = strtol(hash.c_str(), NULL, 16); cout << msgHash << endl; There are no integer large enough to contain the value of 32 byte hexadecimal hash, and so I tried big integer from NTL library but it didn't work out because you cannot assign long integer to NTL::ZZ type. Is there any good solution to this? I'm doing this with visual C++ in Visual Studio 2013.

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  • How to sort a hash by value in descending order and output a hash in ruby?

    - by tipsywacky
    output.sort_by {|k, v| v}.reverse and for keys h = {"a"=>1, "c"=>3, "b"=>2, "d"=>4} => {"a"=>1, "c"=>3, "b"=>2, "d"=>4} Hash[h.sort] Right now I have these two. But I'm trying to sort hash in descending order by value so that it will return => {"d"=>4, "c"=>3, "b"=>2, "a"=>1 } Thanks in advance. Edit: let me post the whole code. def count_words(str) # YOUR CODE HERE output = Hash.new(0) sentence = str.gsub(/,/, "").gsub(/'/,"").gsub(/-/, "").downcase words = sentence.split() words.each do |item| output[item] += 1 end puts Hash[output.sort_by{ |_, v| -v }] return Hash[output.sort_by{|k, v| v}.reverse] end

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  • Is this a HPC or HA mySQL cluster?

    - by Louise Hoffman
    Can someone tell me if this is a High Performance Compute or High Available mySQL cluster? There is a picture of the setup. This is part of the config.ini they talk about [ndbd default] NoOfReplicas=2 # Number of replicas Is it correct understood that NoOfReplicas determines if I have a HPC or a HA cluster?

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  • Solaris cluster - what is running where

    - by Eddy
    Hello, how can one tell which resources (FS, process etc....) are part of a specific cluster configuration? IE: after logging in to the global zone, how can I identify the resources that are running under cluster monitoring? Regards, Edoardo

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  • Rails 3 : create two dimensional hash and add values from a loop

    - by John
    I have two models : class Project < ActiveRecord::Base has_many :ticket attr_accessible .... end class Ticket < ActiveRecord::Base belongs_to :project attr_accessible done_date, description, .... end In my ProjectsController I would like to create a two dimensional hash to get in one variable for one project all tickets that are done (with done_date as key and description as value). For example i would like a hash like this : What i'm looking for : @tickets_of_project = ["done_date_1" => ["a", "b", "c"], "done_date_2" => ["d", "e"]] And what i'm currently trying (in ProjectsController) ... def show # Get current project @project = Project.find(params[:id]) # Get all dones tickets for a project, order by done_date @tickets = Ticket.where(:project_id => params[:id]).where("done_date IS NOT NULL").order(:done_date) # Create a new hash @tickets_of_project = Hash.new {} # Make a loop on all tickets, and want to complete my hash @tickets.each do |ticket| # TO DO #HOW TO PUT ticket.value IN "tickets_of_project" WITH KEY = ticket.done_date ??** end end I don't know if i'm in a right way or not (maybe use .map instead of make a where query), but how can I complete and put values in hash by checking index if already exist or not ? Thanx :)

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  • Exchange 2007 two node cluster setup on Windows 2008 Enterprise, install error

    - by Shadow00Caster
    I am installing Microsoft Exchange 2007 x64 in a two node environment using Microsoft Windows 2008 Enterprise x64. The Failover Cluster is all setup properly and following best practices for setting up the windows clustering for use with Exchange 2007. All the validation tests pass on the cluster and all of that portion is working fine. The problem is when I go to install the first Exchange node as an Active mailbox in configuration for a two node CCR. It gets all the way through the first 3 steps (Copy Exchange Files, Management Tools, Mailbox Role) and then fails on the 4th step 'Clustered Mailbox Server' with the following error: Error: The clustered mailbox server's group 'XXXX' was not found, and should already exist. Firewalls are all disabled, DNS is all setup properly, the environment has 3 domain controllers all 2k8 ent x64, all replication works. The name I pick for the CCR cluster (XXX) does not exist in AD or in DNS. I have attempted this install from both of the two Exchange nodes and multiple times .. tried with different names. I have been banging my head against the wall for days working on this and would appreciate any feedback on the issue.

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  • Hyper-V virtual machine can't be migrated to a specific host in the cluster

    - by Massimo
    I have a three-node Hyper-V cluster running on Windows Server 2008 R2 which is working quite flawlessly: there are no errors, live migration works, all hosts can and will happily run all virtual machines, and so on. But one specific virtual machinee is trying to make me go mad: it works on two nodes of the cluster, but not on the third one. Whenever I try to move the VM to that node, be it in a live migration or with the VM powered off, it always fails. In the event log of the host these events are logged: Source: Hyper-V-VMMS Event ID: 16300 Cannot load a virtual machine configuration: General access denied error (0x80070005) (Virtual machine ID <GUID>) Source: Hyper-V-VMMS Evend ID: 20100 The Virtual Machine Management Service failed to register the configuration for the virtual machine '<GUID>' at 'C:\ClusterStorage\<PATH>\<VM>': General access denied error (0x80070005) Source: Hyper-V-High-Availability Event ID: 21102 'Virtual Machine Configuration <VM>' failed to register the virtual machine with the virtual machine management service. All other VMs can be moved to/from the offending host, and the offending VM can be moved between the other two hosts. Also, this is not a storage problem, because there are other VMs in the same cluster volume, and the host has no troubles running them. What's going on here?

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  • Mysql Cluster not working on Ubuntu

    - by user53864
    I am unable to setup MySQL Cluster on ubuntu servers. As a starting point I started from the link but I am not successful and the tar ball version I download is 6.3.45. As I wanted to test the mysql cluster, the Data node and SQL node are same but sql never appeared as connected in management node console and it looks like below. [ndbd(NDB)] 2 node(s) id=2 @192.168.1.107 (Version: version number, Nodegroup: 0, Master) id=3 @192.168.1.108 (Version: version number, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 @192.168.1.105 (Version: version number) [mysqld(API)] 2 node(s) id=4 (not connected, accepting connect from 192.168.1.107) id=5 (not connected, accepting connect from 192.168.1.108) On all the 3 machines mysql-server & client(apt-get install mysql-server mysql-client) were already installed and I completely stopped and also removed them at the system start up. Now the mysqld is from extracted cluster tar ball(/usr/local/mysql/support-files/mysql.server). As for testing, I created a test database on both the data nodes but the tables are also not syncing on other node. I checked many links, configurations are remained similar in all the links but somewhere it's going wrong. Anymore extra package is required?, Could anyone help me here..?. I am trying this for past 3 days... Thank you!

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  • Mysql ndb cluster - node restart.

    - by Arafat
    Hi guys! I just setup a mysql cluster on a fairly decent baby (IBM x3650 M3) with 24GB memory, xeon 6core, SAS 6Gbps HDD. Running Debian Lenny 5. 64bits. Ndb version is 7.1.9a. Our database size on MyISAM is around 3.2 GB. Ndb_size estimation is 58GB for ndbengine. A little info about my database is as follows. 150 common tables for global purpose. 130 tables for each clients. So it goes like this, 130 x 115(clients) = 14950 tables. Is it normal or usual to have 14000 tables on one database? The reasons why we did this was, Easy maintenance and per client based customization. Now, the problem is, ndb cluster can only support, 20320 tables. But it can support 5,000,000,000 rows in one table if I'm not wrong. My real head ache is my cluster data node takes less than two minutes to startup with out any data. But as soon as convert my tables into ndb, that too only 2000 tables, data node takes at least 30 to 40 mins to start up. Is it normal? If I convertt all my tables into ndb, will it take even longer? Or let's say if consolidate my 14000 table's data into one, which is 130 tables, will it help? Or is there anything idiotically wrong which I'm doing? I'll attach my config.ini file soon. here's the simple overview of my config Datamemory = 14G Indexmemory = 3GB Maxnooftable = 14000 Maxnoofattributes = 78000 I'm just testing these values with 2000 tables first. Please advise, how to increase the start up speed. Please point out where I'm going wrong. Thanks in advance guys!

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  • hyper-v cluster behavior when losing network connectivity

    - by ChristopheD
    Setup: (rather new) Hyper-V R2 cluster with 2 nodes (in failover configuration). Fysical host OS: Windows Server 2008. About eight VM's (mixed: Windows Server 2008 and Linux) Yesterday we had a power outage of about 15 minutes. Our blades are on UPS so the fysical host machines (Windows Server 2008) never went down. Our main switches are not on UPS (yet) and we saw the behaviour similar to the following (as distilled from the event logs). The nodes in the cluster lost means of communication (because the external switches went down). The cluster wants to bring down one (the first) of the nodes (to start failover?). The previous step impacts clustered storage where the virtual machine VHD's are located. All VM's got brutally terminated and were found in a failed state in the failover manager in the host OS'es. The Linux VM's were kernel panicking and looked like they had their disk ripped out. This whole setup is rather new to us, so we are still learning about this. The question: We are putting switches on UPS soon but were wondering if the above is expected behavior (seems rather fragile) or if there are obvious improvements configuration-wise to handle such scenario's ? I can upload an evtx file concerning what exactly was going on in case that's necessary.

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  • Experience with asymmetrical (non-identical hardware) SQL Server 2005 / Win 2003 cluster

    - by user24161
    I am reasonably good at dealing with SQL Server clusters; I am wondering if folks have experience, good or bad, using a mix of different models of servers from the same vendor in one SQL 2005 cluster. Suppose: I have one more powerful, more RAM, more shizzle box and one less powerful, less memory, less shizzle box bound together in a 2-node cluster. These would be HP DL380 and 580 machines (not that it should matter) I understand AND automate the process of managing memory for each SQL instance, so there's no memory contention when SQL instances fail over. Basically I am thinking a CLR proc will monitor the instances and self-regulate memory caps on each instance, so that they won't page or step on one another. I get the fact the instances might be slower and or under memory pressure if they share a "lesser" node, and that's OK. The business can deal with a slower instance in a server-problem scenario. Reasonable? Any "gotchas" to watch out for? More info 10/28: doing some experiments with a test cluster I find that reconfiguring max/min memory is OK PROVIDED the instance isn't already under memory pressure. If I torture the system with a huge query that demands a big chunk of RAM, and simultaneously adjust the memory allocation to a smaller value than what is being actively used, it's possible to run the instance out of memory and have it halt and restart itself (unhappy situation). Many ugly out-of-memory messages in the error log, crashing, burning... It's an extreme case, but good to know. Seems, then, that it would only be really safe to set this on startup of the instance, as in have a startup script that says "I am on node1, so my RAM settings are X or I am on node two, so they are Y," like this: http://sqlblog.com/blogs/aaron_bertrand... Update: I am testing a SQL Agent + PowerShell solution described in more detail here.

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  • PHP hashing function not working properly

    - by Jordan Foreman
    So I read a quick PHP login system securing article, and was trying to sort of duplicate their hashing method, and during testing, am not getting the proper output. Here is my code: function decryptPassword($pw, $salt){ $hash = hash('sha256', $salt . hash('sha256', $pw)); return $hash; } function encryptPassword($pw){ $hash = hash('sha256', $pw); $salt = substr(md5(uniqid(rand(), true)), 0, 3); $hash = hash('sha265', $salt . $hash); return array( 'salt' => $salt, 'hash' => $hash ); } And here is my testing code: $pw = $_GET['pw']; $enc = encryptPassword($pw); $hash = $enc['hash']; $salt = $enc['salt']; echo 'Pass: ' . $pw . '<br />'; echo 'Hash: ' . $hash . '<br />'; echo 'Salt: ' . $salt . '<br />'; echo 'Decrypt: ' . decryptPassword($hash, $salt); Now, the output of this should be pretty obvious, but unfortunately, the $hash variable always comes out empty! I'm trying to figure out what the problem could be, and my only guess would be the second $hash assignment line in the encryptPassword(..) function. After a little testing, I've determined that the first assignment works smoothly, but the second does not. Any suggestions? Thanks SO!

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  • MySQL Cluster data nodes - slow SELECTs

    - by Boyan Georgiev
    Hi to all. First off, I'm new to MySQL Cluster. This is my pain: I've managed to setup a MySQL Cluster with two data nodes, two SQL nodes and one management server. Everything works pretty well, except the following: my data nodes are spread across an intranet link which incurs latency into communications between the data nodes. Apparently, due to MySQL Cluster's internal partitioning schemes, when my PHP application pulls data from the cluster via SELECT queries, parts of the data are pulled from both data nodes. This makes the page appear onscreen REALLY slowly. If I bring one data node offline, the data can only be pulled from that single remaining data node, and thus, the final result (HTML output) appears on the screen in a very timely fashion. So, my question is this: can the data nodes/cluster be told to pull data from partitions stored only on a particular data node?

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  • Reaping the Benefits of the Image Packaging System

    - by rickramsey
    source One of the promises made about Oracle Solaris 11 was easier installation. Remember? Do you also remember how involved installing Oracle Solaris Cluster used to be? It was so involved, in fact, that we (when we were Sun Microsystems) wouldn't even let you do it yourself. How times have changed. New - How to Automate The Installation of Oracle Solaris Cluster 4.0 Thanks to the new image packaging architecture in Oracle Solaris 11, you can now automate the installation of Oracle Solaris Cluster 4.0. Why is that such a big deal? As Lucia Lai explains it: "Without the AI, you would have to manually install the cluster components on the cluster nodes, and then run the scinstall tool to add the nodes to the cluster. If, instead, you use the AI, both the Oracle Solaris 11 and the Oracle Solaris Cluster 4.0 packages are installed onto the cluster nodes directly from Image Packaging System (IPS) repositories, and the nodes are booted into a new cluster with minimum user intervention." Lucia goes on to explain how to set up and configure the AI server, how to plan your cluster configuration for the automated installation, how to use the scinstall utility, how to set up the DHCP server, and more. A thorough, well-written article. - Rick Website Newsletter Facebook Twitter

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  • How to cluster two IIS servers for failover?

    - by Ram Gopal
    We have IIS servers running in 2 machines hosting few webservices which provided some integration services to an old document Mgmt system, word/excel related service, etc.... We need to cluster/load balance these 2 IIS in order to achieve a fail-over. i.e If one of the IIS server is down, the other on should be able to handle the request. The reverse proxy used in the DMZ is also IIS 7.5 Our overall business application is in fact a J2EE one and we have successfully deployed on a weblogic cluster installed on the same two machines and load balance from the same above mentioned IIS reverse proxy at DMZ. But we do not know how to achieve this in case of IIS.

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  • Hyper-V Cluster with failover - NETWORKING

    - by Adam
    Hi We are looking to setup a 3 node Hyper-V cluster with live migration and failover using: 3 x Dell R710's with dual quad core Xeon & 128 GB RAM & 6 NICs in each 1 x Dell MD 3220i SAN We will be running this setup from a data center and so co-locating our kit. Can anybody explain how we should setup the network connections to make the system redundant? We have looked into this great article but are not sure how to get a 3 server setup correctly and reliably: http://faultbucket.ca/2011/01/hyper-v-failover-cluster-setup/. I believe we need network connections for: live migration, heartbeat, management, hyper-v etc. I assume as we are running it from a DC all IPs will have to be public IPs? Are AD servers will be VMs. One on each Hyper-V server and setup not to be HA.

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  • How to remove an "extra" (unwanted) network from a windows 2008 failover cluster?

    - by Trondh
    Hi, We had a severe crash on one node of our 2-node Windows 2008 / Exchange 2007 CCR Cluster the other day, and i tried to rebuild the node from scratch. I'm using this as a rough outline: http://edmckinzie.spaces.live.com/Blog/cns!687C72A5909E4230!508.entry?sa=641979772 The problem: Our cluster was originally setup with only one NIC per host, as this is supposedly supported in Win2008 (no dedicated heartbeat NIC). When I add my freshly installed node to the cluster, it shows up with two cluster networks, "Cluster Network 1" & 2. The existing node's NIC has been placed in one cluster network and my fresh installed has ended up in the other. I can't find anywhere in the GUI to choose which cluster network each physical NIC should be part of, but i KNOW I have done this before. Time is of the essence on this one, so I was hoping someone in here had the answer on the top of their head... Thanks for any pointers. regards, Trond Hindenes

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