Certain Extent

Modified from Jason Massie’s post, here are queries to tell you your read/write ratio per server and database.  Interesting results if you are maintaining multiple databases/application and are acting under the assumption that they behave similarly:

SELECT
    CAST(SUM(user_seeks+user_scans+user_lookups) AS decimal)
    /
    CAST(SUM(user_updates) + SUM(user_seeks+user_scans+user_lookups) AS decimal)
AS ReadPercent
    , CAST(SUM(user_updates) AS decimal) /
    CAST(SUM(user_updates)
    + SUM(user_seeks + user_scans + user_lookups) AS decimal)
AS WriteRatio
FROM sys.dm_db_index_usage_stats

SELECT db.name
, CAST(SUM(user_seeks+user_scans+user_lookups) AS decimal)
/ CAST(SUM(user_updates)+SUM(user_seeks+user_scans+user_lookups) AS decimal)
* 100 AS ReadPercent
, CAST(SUM(user_updates) AS decimal)
/
CAST(SUM(user_updates)
    + SUM(user_seeks + user_scans + user_lookups) AS decimal)
    * 100 AS WriteRatio
FROM sys.dm_db_index_usage_stats t
JOIN sys.databases db on db.database_id = t.database_id
WHERE (user_updates + user_seeks + user_scans + user_lookups) > 0
GROUP BY db.name
ORDER BY db.name

sqlserver