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7

They can help with replication but they need DB quiecing support, otherwise you'll inherently get data corruption. In my experience it's always far better to get the DB engine itself to do the work - they're designed to do just that.


5

Any time you have a file open you run the risk of having a corrupted copy when you just copy it to another location. As you alluded, Access isn't really meant as a multiuser database and I don't know of utilities that will safely dump the contents to another file the way you can with most SQL databases. You might have some luck using volume shadow copies. ...


4

According to your slave status, replication is up and running correctly. What is likely to be broken are your expectations. MySQL replication is a one-way replication from master to slave without the verification of consistency on the slave. Rows changed on the slave by a third party will not get replicated back to the master but will obviously affect ...


3

I think what you want is replication: see here.


3

The traditional setup would be to separate your web/application server and your DB server. Having them on the same box is going to be pretty restrictive. If your wep application consists of a mix of static and dynamic content then further seperation (a seperate web server, application server and content server) will improve performance. As far as MySQL ...


3

Option 3: BUY THE RIGHT TOOL! You are using Access for something it was never designed for -- High-uptime, high-concurrency, high-volume data storage. Access is a TOY - A pretender to the database throne which is suited for very small projects which aren't business-critical. The use case you describe is what SQL Server was made for. Spend the money and ...


2

Someone has to be turning it on. Sharepoint won't just enable replication by it self. Setup a profiler trace for the replication stored procedures (I can get you some procedures names if needed) to see who is running them. That or enable server auditing for the execution of these procedures.


2

Master-Master approach + You can send update queries to any database server. + If one Master failed, the other one will be ready to take over. - You may have data corruption and/or index conflicts if not setup properly. - You may get inconsistent/incomplete data when one node fails to get updates from the other one. Remember, you will be reading/writing ...


2

It looks like it is possible. SQL Server calls it Database Mirroring, and the key point is to use the "high-safety" mode, which is synchronous. That means that every transaction committed will be committed to both instances before returning as completed. Do note, this will definitely have an impact on performance. And likely a big impact. Every time you ...


2

1) How do you set up multiple web servers while maintaining the same content (would I have to upload the files to all the servers everytime they were updated or is there another way?) Situations get more complicated with scale. Starting out, you would simply deploy all content to all servers at the same time manually. You could write a script to do ...


2

Mirroring that is set up in high-safety mode with the presence of a witness can allow for a switch of the active database instance in a way that is seamless to the application. The catch is that it's a synchronous operation every time there's a transaction... meaning it must be committed on both nodes before the transaction is complete. Therefore, there is ...


2

Ah now that is the ultimate question! You will get 101 responses no doubt but if your question is actually asking which of these technologies is probably best suited to making a database available then I would go for Mirroring every single time. Replication is fantastic for scaling of data, and improving availability of subsets of data. If your question is ...


2

Option 1 definitely sounds the best. Microsoft don't recommend you install Exchange on a Domain Controller, and adding extra disks to an existing server isn't going to protect you if for example the motherboard fails in that machine. For your second server, the best thing you could do is buy the same server and configuration as your existing server. ...


2

Running on a DC can work, but it's kind of fragile. http://support.microsoft.com/kb/940845 <-- MS KB article defining some of the problems. For one, you'll need to tweak some things to make sure the Exchange service start after a reboot. Completely separate storage on the same server is also a valid replication config, though as you note not as robust ...


2

My questions: Is PostgreSQL 9.0.4 a viable DB to use as of now? Are there any known major bugs? Yes, it's a viable database and no, all known bugs are fixed. 9.0 allready had 4 patchrounds, that's why it's 9.0.4. New patches become every 3 to 6 months available. Are there any noticeable performance differences? Yes, but it depends on your ...


2

Before you try anything else, check if DB 2 is a replication slave of DB 1. Execute "SHOW SLAVE STATUS" on DB 2. If it gives you a result, it is likely, that an error occured, that stopped the replication. mysql> SHOW SLAVE STATUS\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event ...


2

The time difference between master and slave is computed when I/O thread starts and it assumed to never change while it runs. It you had a different timezone on one of the servers and it changed without restarting MySQL, then slave is adding the incorrect difference to the report. Restart servers.


2

This question is too big; you'll likely not get specific answers on it. In order to have "multi-master" replication, meaning both servers responding, you need to solve that problem for each protocol separately (SQL, SMB, HTTP, etc.). A much easier route is to only use one server at a time in a active-passive scenario but you're still talking a highly ...


2

On my website I connect to the slave server and I insert some rows, but they do not appear on the master... This will only happen with multi-master replication. In this kind of setup, both servers are masters. This is complicated and it's easy to make mistakes. You won't want to do multi-master for your first time. So, with a normal master -> slave ...


2

A few quick checks: Are you running on 2.0 or below? Replication got a major overhaul in 2.2 Do you have any capped collections? A missing index on _id in a capped collection can cause this kind of lag You mention that the hosts are not too busy - if you have gaps in your new ops, the math used to calculate lag can falsely report lag when no ops are ...


2

As Sandor said, this cannot be done with standard MySQL replication. It can be done if you use a third-party / external replication mechanism. A few products that I'm aware of: Continuent Tungsten Replicator SymmetricDS Both are open source and freely available. Another option would be to migrate to a MySQL cluster. Some options: MySQL Carrier ...


2

It is not possible to run multiple PostgreSQL servers from the same data directory, even if all but one are read-only. Absolutely 100% unsupported. Cannot be done. Give up now. Somebody might one day add such a feature but it'd involve major changes to PostgreSQL, as Pg relies heavily on shared memory and signals for inter-process synchronization. Also, the ...


2

I also just ran into this issue. The key here is actually the archive_cleanup_command in the "recovery.conf" on the standby. The standby will run the archive_cleanup_command command when it is done processing a WAL segment from the primary, so at that point you know you can backup that WAL segment and all prior segments. In my "recovery.conf" I have: ...


1

Seconds_Behind_Master is considered an unreliable measure of Slave lag. mk-heartbeat is the suggested solution. Check out this SF post (by yours truly).


1

If you are using SSMS and specifying anything but what @@servername returns on the server as your connection string, that's your problem. Maybe you've put in a port number, using a DNS alias for the server or anything else like that. RMO (replication management objects, the technology that SSMS is using for the new publication wizard) is silly about the ...


1

PostgreSQL tries very hard to not have any open bugs. There aren't any serious bugs at all, outside of things that are known to be slower than they could be that are impractical to backport, in 9.0 that haven't already been fixed. That said, newer code normally has more unknown bugs than older stuff does, and you can't ever know how many unknown bugs there ...


1

per your first question, replication of system databases isn't supported. Regarding your core issue: Have you traced events that would tell you definitively that this is not being enabled by end-users? If this happens periodically, you may want to audit/trace for related events to make sure that this is indeed the case. The most common reason behind this ...


1

Turning on binary logging (for replication) can severely affect performance. It calls fsync to ensure consistency, so everything is slower. A few articles to read: http://jcole.us/blog/archives/2006/05/25/on-disk-performance-and-mysql-replication/ http://www.mysqlperformanceblog.com/2006/05/27/jeremy-cole-on-mysql-replication/


1

How to build a redundant cluster of servers (From my blog): http://tomoconnor.eu/blogish/dedicated-dedicated/ It's really difficult to give specific models and manufacturers, because that kind of information is really specific and localised. You'll want 2 or more of everything, LOTS of memory, FAST disks. Anything by Dell or HP that fits that category will ...



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