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Questions tagged [replication]

Replication is the process of sharing any level of information so as to ensure consistency between redundant hardware/software resources to improve reliability, fault-tolerance, and accessibility

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95
votes
3answers
128k views

Is it safe to delete mysql-bin files?

I have MM Replication in mysql, and I want to squeeze some free space in the box be deleting unnecessary files, I came across these mysql-bin files inside /var/db/mysql/ There are hundreds of those ...
64
votes
7answers
128k views

How do I completely disable MySQL replication

I am running dual master MySQL replication and now want to move to a single database with no replication. How do I completely disable replication on both databases?
37
votes
3answers
11k views

MySQL 5.1.66 SSL connection error ERROR 2026 (HY000)

UPDATE2 Using WireShark I found out the problem string (I hope I did): 28 | 9.582638 | 192.168.18.128 | 192.168.18.129 | MySQL Response Error 1043 And the error is (according to docs): Error: 1043 ...
25
votes
4answers
48k views

MySQL relay log corrupted, how do I fix it? Tried but failed

A MySQL v5.1.61 relay got corrupted when the machine suddenly shut down. I tried to fix it but it didn't work. — How do I fix it? Did I do something wrong? As far as I've read, corrupted MySQL relay ...
25
votes
2answers
41k views

What is the safest way to switch the binlog format at runtime?

Because of the following warning in mysqld.log: [Warning] Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. The statement is unsafe because it ...
23
votes
5answers
42k views

Add article to transactional publication without generating new snapshot

Using SQL 2008 R2 transactional replication with pull subscribers, when we add an article, I'd like to avoid having to create an entire snapshot (the db is ~80 GB, so this takes hours). From this ...
22
votes
3answers
43k views

Should a MySQL replication slave be set to read only?

I've got replication running on Percona Server 5.5 by following this guide and wondered if I should add read-only=1 to my slave's my.cnf to make it read only? The guide sets up replication for the ...
21
votes
3answers
12k views

Running pg_dump on a hot standby server?

Disclaimer: I admittedly haven't tried this yet, but I'm not sure I would know if it wasn't working correctly, so I wanted to ask. I would like to run a nightly backup job (via pg_dumpall) from a hot ...
21
votes
3answers
9k views

SQL Server database synchronization

Problem definition Our users need the ability to query a database that is mostly up to date. The data can be stale up to 24 hours and that is acceptable. What would be the lowest cost approach to ...
19
votes
3answers
29k views

Postgresql doesn't accept replication connection

Plain old streaming replication. PostgreSQL: 9.2.7 Windows 8.1 64 bit My primary and secondary clusters are on same windows machine. I have already done pg_start_backup() and everything, so both ...
19
votes
3answers
8k views

PostgreSQL: Can I do pg_start_backup() on a live, running db under load?

Our established replication has broken ("requested WAL segment has already been removed" during downtime) We cannot easily stop the master again. Can we do pg_start_backup(), rsync ${PGDATA}/ ...
18
votes
2answers
2k views

What can we do in MySQL 5.0 Replication to address bandwidth concerns?

I am developing an application to run on the client PC (Win) which is configured with a MySQL server 5.1 instance that will act as read-only slave to the remote master. The remote master has dozens of ...
17
votes
3answers
28k views

How to determine master in mysql master-slave

I am setting up MySQL Master-slave replication and I am trying to figure out how to handle the failover situation where I promote the slave to master (in the event that the master goes down). My ...
17
votes
1answer
17k views

In a MySQL Master/Slave replication, what would happen if I write to the Slave?

Several Questions Would the Slave entry remain until there is an insert/update/delete to the table on the Master that could affect the Slave? If not, how do I ensure that the Slave is in-sync with ...
17
votes
5answers
4k views

Infrastructure for Highly Concurrent, High Write DB

My requirements are: 3000 Connections 70-85% Write vs Read Currently, we are maxing out a High-CPU, Extra Large Instance at 700 connections. All 8 cores are maxed. We think it's the number of ...
16
votes
1answer
4k views

Is PostgreSQL replication production ready?

How does PostgreSQL native replication compare to MySQL? I know asynchronous replication has been supported for longer than sync, which is recent. Is synchronous reliable to be used in real projects?
16
votes
1answer
29k views

How soon after updating expire_logs_days param and restarting sql will old binlogs get deleted?

MySQL 5.1.x | InnoDB | Windows My mysql data directory is starting to fill up with bin logs. I currently have the following settings configured in my windows mysql server: [mysqld] log-bin server-...
16
votes
3answers
9k views

Replicate RDS-MySQL to a non-amazon host?

I have a fairly large MySQL (5.1) database running in Amazon as an RDS instance. I'm working on migrating it out of Amazon. To do that smoothly I'd like to set up the new hardware as a read-only ...
16
votes
3answers
4k views

Does PostgreSQL 9.1 Streaming Replication catch up after a lag without WAL archiving?

Context: Let's say that, while using Streaming Replication/Hot Standby on a Postgres 9.1 cluster, a standby node goes down. It stays down for an day, during which time a lot of DML occurs on the ...
15
votes
3answers
5k views

Migrate heroku database to Amazon RDS with minimum downtime

I have a heroku postgres database and want to migrate it to Amazon RDS to save cost. What's a way to do so with minimum downtime? Usually this involves replicating database in real time and then ...
14
votes
2answers
25k views

What is the Best Way to create MySQL Master-Slave Replication Setup and Troubleshoot it?

I am very new to Database Administration. I face a lot of problems while setting up mysql master-slave replication. I also face regular mysql replication troubleshooting issues. Can anybody helps ...
14
votes
2answers
39k views

What max_allowed_packet is big enough, and why do I need to change it?

I have MySQL (5.5) in master-slave setup and created another slave server. I stopped the original slave, dumped the data, copied and reimported and it worked fine. I noted the master_log pos of the ...
14
votes
2answers
19k views

How to backup large MongoDB database

What is the recommended way to back up large data sets in MongoDB? Let's say we have a data size in the order of 10TB - how would you back that up? We're considering a hidden, possibly delayed, ...
14
votes
3answers
14k views

ALTER TABLE on a large table with an indexed column

I have a large table with a VARCHAR(20) column, and I need to modify that to become a VARCHAR(50) column. Typically, performing an ALTER TABLE (adding a TINYINT) on this particular table takes about ...
14
votes
1answer
7k views

SQL Server Many-to-One replication

I have 8 individual SQL Server 2008 R2 machines, each hosting 1 database. Each database has an identical table structure and schema, and entirely unique data. I would like to establish a reporting ...
14
votes
2answers
5k views

Streaming replication and failover on PostgreSQL

I am doing a proof of concept on PostgreSQL replication. After the discussion on forum we decided to go with streaming replication as the performance is good compared to other solutions. PostgreSQL is ...
14
votes
1answer
5k views

PostgreSQL failover and replication

I'm evaluating PostgreSQL 9.1 and have few questions related to failover and replication details. I have few test scenarios. First one with a Master server and few Slaves. In case Master crashes I ...
13
votes
5answers
4k views

Is it unwise to run replication on same physical server?

I'm contemplating setting up a Master-Slave replication for my database. The slave server will be used for redundancy and possibly a reports server. However, one of the biggest issues I'm running into ...
13
votes
1answer
10k views

Replicate tables to different database name

Our QA environment has all it's database names suffixed with "test". For example dbname1 in production would have a counterpart dbname1test in QA. (This is largely to help protect against prod/qa ...
13
votes
2answers
6k views

What are the drawbacks of using Galera Cluster instead of Master/Slave Replication?

What are the drawbacks of using Galera Cluster instead of regular Master/Slave Replication? Galera's 0 slave lag time, Synchronous replication and no Single point of failure seem very appealing then ...
13
votes
2answers
19k views

Mongo DB Replica set Stuck at RECOVERING state

We have created a replica set and now the problem is 2 members of replica set [3 members set] are in recovering mode from 48 hours. Initially the size of recovering nodes was increasing and now even ...
13
votes
1answer
21k views

Deleting bin logs in replication environment

I have a question about deleting binary logs in the replication environment: We have an environment with 1 master and 2 slaves (running mysql 5.5). Sometimes, we run into a space issues during heavy ...
13
votes
6answers
10k views

Transaction Log won't shrink, DB thinks it is replicating

I've got a SQL Server 2008 R2 Express database running Kaspersky Security Center, and I have no idea under what circumstances the install happened, but the database appears to think that it's being ...
13
votes
0answers
761 views

Splitting Snapshot files with MaxBCPThreads for Transactional Replication

I've just set up a publication, and I'm attempting to get the snapshot to apply faster. So far the Distribution Agent is respecting the MaxBCPThreads settings, but the Snapshot Agent is not. I'm ...
12
votes
2answers
14k views

Difference between row-based and statement-based replication in MySQL?

What is the actual difference between row-based and statement-based replication. I am actually looking in terms of replication's effect on the slave. If I am using row-based replication then what is ...
12
votes
3answers
15k views

Replication Monitor Information using T-SQL

The image below shows a transaction replication problem that I am currently investigating. The image comes from the Replication Monitor. How can I get this information using T-SQL?
12
votes
3answers
4k views

Snapshot Replication Retention

I've got Snapshot replication set up on my SQL Server 2008 production server, and I just noticed that there are snapshots ranging back to a year ago in the snapshot folder. How can I change the ...
12
votes
1answer
7k views

Upgrade SQL Server 2005 to SQL Server 2012

I have a test environment set up with the following: Virtual Machine (Hyper-V) Windows Server 2008 R2 SP1(x64-bit) Windows SQL Server 2005 Developer Edition SP4 (x64-bit)(default instance name) 1 ...
11
votes
3answers
28k views

MySQL replication - slave is continuously lagging behind master

I am using MySQL-5.1.50 with a Master-slave replication setup. Most of the time the slave is lagging behind the master. When I run show processlist;, there is no query that's taking a long time. ...
11
votes
2answers
25k views

Trying to understand SHOW SLAVE STATUS in MySQL

I have a Master-Slave replication setup and it looks like that it is running fine. Below is a result of SHOW SLAVE STATUS command: show slave STATUS\G; *************************** 1. row *************...
11
votes
1answer
14k views

How do I (safely) kill long running operations in MongoDB?

Occasionally operations get out of control in MongoDB and might end up running for hundreds of seconds, and impact performance until they are killed or completed. When that happens, I know I have ...
11
votes
3answers
18k views

How do you re-sync the Master MySQL DB with Slave DB changes if the Master goes offline?

MySQL Server 1 is running as Master. MySQL Server 2 is running as Slave. With both DBs online, they are in "perfect sync". If Slave goes offline, there's no problem if Master still online; they will ...
11
votes
3answers
5k views

Is MySQL Replication Affected by a High-Latency Interconnect?

We've got a vanilla master and slave MySQL setup that reside in different data centers, and another slave in the same datacenter as the master. The bandwidth between the datacenter is pretty high (in ...
11
votes
1answer
4k views

Does SQL Server Snapshot replication completely copy the data every time or does it issue deltas?

I am looking at snapshot replication between two servers. Here is what I have: 500GB database ~500MB nightly bcp loads ~50MB daily transactions I was asking other DBAs in the company about which ...
11
votes
2answers
8k views

Impact of changing the DB compatibility level for a Published replicated DB from 90 to 100

I have a SQL Server 2008 R2 server with a bunch of published databases that are currently operating under compatibility level 90 (2005). The subscription databases are also SQL Server 2008 R2, ...
11
votes
2answers
155 views

What objective factors indicate it's time to implement SQL Server replication?

I am trying to strike a balance between high performance of our database and ease of maintenance. We are considering using replication to improve performance, by replicating our SSRS reports to a ...
11
votes
1answer
610 views

How do data checksums interact with streaming replication?

Data checksums are a new feature introduced in 9.3, and: there is a new GUC parameter "ignore_checksum_failure" which will force PostgreSQL to continue processing a transaction even if corruption ...
10
votes
4answers
34k views

How to change a MySQL previous slave to be a master and remove slave status information?

I have a master -> slave configuration where the master failed. I've been able to reset the old-slave to be a master and the old-master to slave from it. Fine. What I can't seem to do is to remove ...
10
votes
4answers
25k views

Replicating a remote MySQL database to MS SQL Server 2008

I want to replicate the contents of a MySQL database to a MS SQL Server 2008 database. Is this possible? Can anyone outline the steps required in order to achieve this? Thanks.
10
votes
1answer
202 views

What is a “hashed transaction” in SQL Server Replication terminology?

sys.dm_repl_tranhash contains information about the hashing of transactions, but I have difficulties understanding the terminology. What is a "hashed transaction"?