durability | 易学教程

What does it take to be durable on Linux?

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问题 I'm writing some software to deal with pretty critical data, and need to know what exactly I need to do to achieve durability. Everywhere I look is contradictory information, so I'd appreciate any insight. There are three ways I write to disk. Using O_DIRECT | O_DSYNC, and pread'ing and then pwrite'ing 512 byte - 16 MB blocks. Using O_DIRECT, pread'ing and then pwrite'ing 512 byte blocks, and calling fdatasync as regularly as necessary. Using a memory mapped file, which I call msync(..., MS

How to avoid data loss on server failure with MongoDB on a single machine?

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问题 I have read that mongoDB don't write data to disk right away, it does this periodically. Any thoughts on how to deal with this? 回答1: You can enable journaling with --journal . Check out http://www.adathedev.co.uk/2011/03/mongodb-journaling-performance-single.html and http://www.mongodb.org/display/DOCS/Durability+and+Repair 回答2: Besides --journal that is enabled by default since MongoDB 2.0 ( only on 64 bit machines), there is a flag that you can set when persisting data: safe => false : do

Are there databases that bases durability on redundancy and not on persistent storage?

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问题 Sorry that the title isn't exactly obvious, but I couldn't word it better. We are right now using a conventional DB (oracle) as our job queue, and these "jobs" are consumed by some number of nodes (machines). So the DB server gets hit by these nodes, and we have to pay a lot for the software and hardware for this database server. Now, it occurred to me the other day that, 1) There are already multiple nodes in the system 2) "Jobs" may not be lost because of node failures, but there is no

99.99% durability. What does it mean? [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 7 years ago . Amazon S3 offers two plans: Storage (Designed for 99.999999999% Durability) and Reduced Redundancy Storage (Designed for 99.99% Durability) Designed to provide 99.999999999% durability and 99.99% availability of objects over a given year. Heres the link So if I have 10 000 files I can expect to loose one in

How to avoid data loss on server failure with MongoDB on a single machine?

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I have read that mongoDB don't write data to disk right away, it does this periodically. Any thoughts on how to deal with this? You can enable journaling with --journal . Check out http://www.adathedev.co.uk/2011/03/mongodb-journaling-performance-single.html and http://www.mongodb.org/display/DOCS/Durability+and+Repair Besides --journal that is enabled by default since MongoDB 2.0 ( only on 64 bit machines), there is a flag that you can set when persisting data: safe => false : do not wait for a db response safe => true : wait for a db response safe => num : wait for that many servers to have