Azure SQL Database DTU percentage metric

Question

With the new Azure SQL Database tier structure  it seems important to monitor your database  DTU  usage to know whether to upgrade or downgrade to another tier   When reading Azure SQL Database Service Tiers and Performance Levels  it only talks about monitoring with CPU  Data and Log percentage usage   But  when I add new metrics  I also have an DTU percentage option     I can t find any about this online   Is this essentially a summary of the other DTU-related metrics

User · Answer

From this document  this DTU percent is determined by this query   SELECT end time        SELECT Max v         FROM  VALUES  avg cpu percent    avg data io percent     avg log write percent   AS        value v   AS  avg DTU percent     FROM sys dm db resource stats      looks like the max of avg cpu percent  avg data io percent and avg log write percent  Reference   https   docs microsoft com en-us sql relational-databases system-dynamic-management-views sys-dm-db-resource-stats-azure-sql-database

User · Answer

A DTU is a unit of measure for the performance of a service tier and is a summary of several database characteristics  Each service tier has a certain number of DTUs assigned to it as an easy way to compare the performance level of one tier versus another      Database Throughput Unit  DTU   DTUs provide a way to   describe the relative capacity of a performance level of Basic    Standard  and Premium databases  DTUs are based on a blended measure   of CPU  memory  reads  and writes  As DTUs increase  the power offered   by the performance level increases  For example  a performance level   with 5 DTUs has five times more power than a performance level with 1   DTU  A maximum DTU quota applies to each server    The DTU Quota applies to the server  not the individual databases and each server has a maximum of 1600 DTUs  The DTU  is the percentage of units your particular database is using and it seems that this number can go over 100  of the DTU rating of the service tier  I assume to the limit of the server   This percentage number is designed to help you choose the appropriate service tier   From down toward the bottom of this announcement      For example  if your DTU consumption shows a value of 80   it   indicates it is consuming DTU at the rate of 80  of the limit an S2   database would have  If you see values greater than 100  in this view   it means that you need a performance tier larger than S2       As an example  let   s say you see a percentage value of 300    This   tells you that you are using three times more resources than would be   available in an S2   To determine a reasonable starting size  compare   the DTUs available in an S2  50 DTUs  with the next higher sizes  P1     100 DTUs  or 200  of S2  P2   200 DTUs or 400  of S2    Because you   are at 300  of S2 you would want to start with a P2 and re-test

User · Answer

To check the accurate usage for your services be it is free  as per always free  or 12 months free  or Pay-As-You-Go  it is important to monitor the usage so that you know upfront on the cost incurred or when to upgrade your service tier   To check your free service usage and its limits  Go to search in Portal  search with  Subscription  and click on it  you will see the details of each service that you have used   In case of free azure from Microsoft  you get to see the cost incurred for each one   Visit Check usage of free services included with your Azure free account    Hope this helps someone

User · Answer

DTU is nothing but a blend of CPU  memory and IO  Why do we need a blend when these 3 are pretty clear  Because we want a unit for power  But it is still confusing in many ways  eg  If I simply increase memory will it increase power DTU   If yes  how can DTU be a blend  It is a yes  In this memory-increase case  as per the query in the answer given by jyong  DTU will be equivalent to memory since we increased it   MS has even a pricing model based on this DTU and it raised many questions  Because of these confusions and questions  MS wanted to bring in another option  We already had some specs in on-premise  why can t we use them  As a result   vCore pricing model  was born  In this model we have visibility to RAM and CPU  But not in DTU model  The counter argument from DTU would be that DTU measures are calibrated using a benchmark that simulates real-world database workload  And that we are not in on-premise anymore     Yes it is designed with cloud computing in mind but is also used in OLTP workloads   But that is not all  Now that we are entering the pricing model the equation changes  The question now is about money and the bundle what all features are  included   Here DTU has some advantages the way I see it  but enterprises with many existing licenses would disagree   DTU has one pricing Compute   Storage   Backup   Simpler and can start with lower pricing  vCore has different pricing  Compute  Storage   Software assurance is available here  Enterprises will have on-premise licenses  this can be easily ported here so they get big machines for less price than DTU model   Plus they commit for multiple years and get additional discounts   We can switch between both when needed so if not sure start with DTU Basic Standard Premium   How can we know which pricing tier to use  Go to configure menu as given below   on the right left you can switch between both    Even though Vcore is bigger  machine  and for bigger things  the cost can sometimes be cheaper for enterprise organizations  Here is a proof  DTU costs  147   But Vcore costs  111  That is because you can commit for 3 years but still pay monthly  and also because of the license re-use option enterprises will have on-premise licenses     It is a bit too much than answering direct question but I am gonna go ahead and make this complete by answering  how to choose between different options in DTU let alone choosing between DTU and vCore   This is answered in this beautiful blog and this flowchart explains it all

User · Answer

Still not cool enough to comment  but regarding  vladislav s comment the original article was fairly old  Here is an update document regarding DTU s  which would help answer the OP s question   https   docs microsoft com en-us azure sql-database sql-database-what-is-a-dtu

[azure] Azure SQL Database "DTU percentage" metric

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