Does anybody have an idea why we have these hourly spikes in CPU usage on our Amazon RDS database?
We don't have any crons running every hour so it seems to be some internal RDS stuff because it's exactly every hour.
Does RDS do some index updates or something every hour?
What's the best way to find out what is causing this?
We have a number of RDS instances running, from micros up to larges, and I don't see this pattern anywhere - so I suspect that it is something in your code.
Probably the best option to figure out what is going on is to be logged into the database at the top of the hour, and monitor what is connecting and what they're doing. For mysql, you can probably start with SHOW FULL PROCESSLIST. There are monitoring tools that will monitor this for you.
You can enable slow and general log on MySQL server and analyze them using pt-query-digest
also there are some commercial tools like MEM and MONyog which can be handy in monitoring SQL queries.
Related
I am using mysql workbench for taking a backup/dump of my database hosted on Amazon RDS service. My database is very huge (about 8gib) and taking a 9-10 hours to download it from read-replica, mean while I am not able to see If download process is stuck or running.
Is there any GUI tool available to take a backup fast and can also give details of which process is running like which table is downloading with its row details or percentage of total download. Mysql workbench is a good tool, but It hasn't show all the options given in 'mysqldump' command utility, and It is also very slow. and I also doubt about my data integrity. can someone explain me how it's work specially with data integrity?
Thanks
First of all, your 8GB database is by no means 'huge'. Second, I'm not clear on what you're trying to do? Amazon provides multiple ways for you to have backups.
From: http://aws.amazon.com/rds/faqs/
Q: Do I need to enable backups for my DB Instance or is it done automatically?
By default and at no additional charge, Amazon RDS enables automated backups of your DB Instance with a 1 day retention period.
How to find which process/query consume CPU in amazon mysql RDS instance? I have medium instance on amazon RDS of mysql, and It is working smoothly previously, but since yesterday Its throwing error 'connection timeout' while accessing RDS instance. When I checked cloud watch, It shows me high CPU utilization during that period. Now I want to check what is the problem? So, can some one tell me how to check it?
thanks
use 'show processlist' in mysql. with this you can see which queries are in what state, doing what, since when
also check slow query log:
http://dev.mysql.com/doc/refman/5.0/en/slow-query-log.html
Using show process list, you can see only current running thread info, but as per context of your query, you want to see the historical status. You can achieve it via enabling the slow query log and setting long query time to 1 second. You can pass slow query logs to cloud watch and can set alerts according to your db system loads and types of queries.
I would like to do a daily mysqldump to my own local disk out side of the amazon eco-system. I have few reasons I want to do this daily.
I want to be in more control of my database when RDS\EBS goes down again.
RDS only allows you to restore within the same availability zone. This really gets me because a natural disaster or network fault at the availability zone pretty much renders backups useless because you can only restore to the same zone. :/
Would like a sandbox/test database where I don't have to pay for space and bandwith.
My big question is if I do a daily mysql dump of a 50gb database will my bandwidth\IO costs skyrocket? I'm assuming they will! Has anyone done something like this before?
UPDATE:
I am running a Multi-AZ production environment be recent outages still proved that there is no such thing as complete failover.
Our company has two services, a front facing web site and internal processing. It's most important that our internal operations don't stop. Our web site could go dark for several hours if need be. Having a recent mysql dump at my figure tips seem priceless to me.
So you have a few points of concern that you note.
With regard to being in control of your database, I am not really sure what you are getting to here. If your production DB goes down, you don't have control over it. Even if you have a local backup of it, that isn't going to do you much good if you don't have a place to host that data.
Is your current production RDS instance a multi-AZ instance to help shield against AZ outtage? If it is, the fail over would happen automatically for you.
RDS snapshots are available to restore in different availability zones. See the documentation for rds-restore-db-instance command line at this link http://docs.amazonwebservices.com/AmazonRDS/latest/CommandLineReference/CLIReference-cmd-RestoreDBInstanceFromDBSnapshot.html
Note that you can specify which AZ you want to restore to.
Based on a daily backup of 50GB, you would be talking about spending $180 in data transfers for backups alone. It would be MUCH cheaper to simply have a small test RDS in the same region as your production RDS instance for testing (I think it is like $5/month for a micro). All your data transfer between these boxes (i.e. moving snapshots onto it) would be free.
You can do the math on pricing yourself here: http://aws.amazon.com/rds/#pricing
This is not to mention that doing your daily backups against production would interrupt your production DB access for the time it locks the DB to perform the dump. This is of course unless you pay to have an RDS read replica that you can take the dumps from.
Finally, there are subtle differences between RDS and a standalone MySQL server in regards to how they are configured, I would much rather have my testing environment be as similar to my production environment as possible.
Just try it. I pull from Amazon to my local mysql-server which is Ubuntu.
mysqldump signs -h signs.c3x4aregvxxx.us-east-1.rds.amazonaws.com -P 3306 -u cartersxxx -pxxxxxx | mysql -u root -pxxxxxx signs
I have been unable to predetermine billing at Amazon and I am actively trying to get away from them. FYI I pay $72/month for 10GB mysql with low bandwidth. IMHO table size dictates cost.
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I realize a couple of basic differences between the two, i.e.
EC2 is going to be cheaper
RDS I wouldn't have to do maintenance
Other than those two, are there any advantages to running my database from RDS as opposed to a separate EC2 server acting as a MySQL server. Assuming similar instance sizes, are both going to run into the same limitations in terms of being able to handle a load?
To give you a little bit more info about my use, I've got a database, nothing too big or anything (biggest table 1 million rows), just high SELECT volume.
This is a simple question with a very complicated answer!
In short: EC2 will provide maximum performance if you go with a RAID0 EBS. Doing RAID0 EBS requires a pretty significant amount of maintenance overhead, for example:
http://alestic.com/2009/06/ec2-ebs-raid
http://alestic.com/2009/09/ec2-consistent-snapshot
EC2 without RAID0 EBS will provide crappy I/O performance, thus it's not even really an option.
RDS will provide very good (though not maximum) performance out of the box. The management console is fantastic and it's easy to upgrade instances. High availability and read only slaves are a click away. It's REALLY awesome.
Short answer: Go with RDS. Still on the fence? Go with RDS!!! if you enjoy headaches and tuning every last little bit for maximum performance, then you can consider EC2 + EBS RAID 0. Vanilla EC2 is a terrible option for MySQL hosting.
In this post there is an excellent benchmark between:
Running MySql on a Small EC2 + EBS
Running MySql on a Small EC2 + EBS + adjusted MySql parameters
A Small RDS
The benchmark is very good since it is not focused only in ideal conditions (only one thread) but also in more realistic scenarios, with 50 threads hitting the database.
RDS is not really a high availability system. Read the fine print in the RDS faq. During a failover event it can take up to 3 minutes to failover. Additional amazon will decide it needs to "upgrade" your rds instance and do a failover at that point which will take your database down for "up to 3 minutes" (our experience is that it can take a longer than that).
RDS high availability is very different than master - master or master - slave replication and is much slower. They don't use mysql replication but uses some kind of ebs replication. So in a failover situation it will mount the ebs on the backup machine, start mysql, wait for mysql to do failure recover (hopefully nothing got corrupted too bad), then do a dns switch.
I hope this helps you with you evaluation.
We chose to use EC2 MySQL instances because we have a high read volume and need master-slave replication. Of course, you can spin up multiple RDS instances and setup MySQL replication between them yourself, but we use Scalr.net, which manages that for you using EC2 instances.
Basically, we just tell Scalr how many MySQL instances we want at it keeps them up, automates the setup of replication, handles automatic failover of slave promotion to master if the master gets terminated etc. It does both SQL dump backups and EBS volume snapshots of the master. So, when it needs to create a new slave, it automatically temporarily mounts an EBS volume of the last master snapshot to initialize the slave DB, then starts replication from the appropriate point. All point and click :)
(and no, I don't work for Scalr or anything. Scalr is available as Open Source if you don't want to use their service)
Regarding the maintenance window question. If you use Multi-AZ then RDS will create a standby replica in another availability zone so that there's no down time for maintenance and you protect yourself against a zone failure.
That's what I'm planning to do in the next week or so. Of course it's going to cost you more but I haven't worked that bit out yet.
MySQL on EC2 vs RDS MySQL
Advantages of MySQL on EC2
Amazon EC2 Inter Region Replication
Copy Snapshots across Amazon EC2 regions
RAID 0 with EBS Striping in MySQL EC2
More than 3TB of Disk space ( You will not need this for your size) can be attached on MySQL on EC2.
Disadvantages of MySQL on EC2
Configuration, Monitoring and Maintenance compared to RDS
Point in time backups available in RDS
IOPS lesser than RDS MySQL ( even after RAID 0) currently, 10800 with 6 disks for MySQL on EC2 whereas 12500 IOPS 16KB on RDS MySQL
I have been trying out RDS for a few months and here are some issues I have:
Using SQL profiler is tricky. Since you cannot connect profiler directly to the server, you have to run some stored procedures to create a log file that you can analyze. While they offer some suggestions about how that is done, it is far from user friendly. I would only recommend that you have a certified SQL professional do this kind of work.
while Amazon backs up your instance, you cannot restore an individual database. I have a web app with several separate customer-specific databases and my solution was to launch an EC2 instance with SQL running on it to attach to the production RDB database and import the data and then back it up on the EC2 instance. The other solution was to use a 3rd party tool that creates a massive SQL script (on the app server) that will recreate the schema and populate the data back to a restore point.
I had the same question this weekend. There is a 4 hour downtime window per week for RDS where they do maintenance. RDS seemed more expensive if you can get away with a micro instance of EC2. (This is true of test instances which has minimum traffic) I also wasn't able to change the timezone of the RDS instance because I dont have permission.
I am now actually looking at http://xeround.com/ which is mysql on EC2 by another company. They do not use InnoDB, instead they have their own engine called IDG. I am just starting to investigate that but they are in BETA and will give 500MB of space.
Does anyone knows any free alternative MySQL Enterprise Monitor?
I need some tool, that allows me to monitor my 3 servers with replication without having to open ssh console, and use command line.
Regards,
Pedro
See the answer to a similar question by themattreid here: How to monitor MySQL query errors, timeouts and logon attempts?
He recommended looking at kontrollbase: http://kontrollsoft.com/software-kontrollbase lots of functionality and is open source.
I wrote an open source tool called MySQLMonk that can monitor replication.
This Could be the tool you are looking for its called MONyog. It does quit a neat job as far as MySQL admin operations are concerned and has a great maintenance cycle.
MONyog - MySQL Monitor and Advisor has separate Replication tab which shows Replication topology of all MySQL servers in your environment.
MONyog has so many other features which can be helpful for DBA activities like Find problem SQL, Trend analysis, Alerts on critical conditions and 200+ Advisors which makes it a complete MySQL monitoring solution.