Indunil Jayasooriya wrote: > Hi All, > > I am learning iostat command to understand disk I/O statistics. > > We have 2 Centos 4 servers running where oracle is installed.We > installed them 2 weeks ago. @ that time, These Servers performed well. > But, Now We have come to know that these 2 Machines are quite slow > when comparing to the first week. > > So, Some say, run iostat to see statictics. I am not familiar with comamnd well. > > I found below url > > http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/admin-guide/s1-resource-rhlspec.html > > as the page says, `man iostat` for more information i typically run something like # iostat -x 5 and ignore the first sample.. every 5 seconds this will output information on disk IO by drive volume. I find the await a particularly important, as its the amount of time disk IO operations are staying queued waiting for the drive, if this gets up tnio the 1000mS range you have a serious bottleneck you said Oracle. to manage and maintain a production Oracle database server, you need an experienced Oracle Data Base Administrator ("DBA") who can optimize and tune and maintain the database. such a person will be very familiar with tracking query and tablespace IO statistics, identifying bottlenecks and restructuring things to achieve optimal performance