SQL Server Performance Forum – Threads Archive

read write ratio

I need to find out the current read write ratio of my database. How do I do that?

Consult BOL Administering SQL Server/Monitoring Server Activity/Monitoring with System Monitor. There you will find a wealth of information regarding what you are trying to do.

Now that is a lazy dba… What specifically are you looking for? I did put in "read write ratio" in books online, and that did work pretty good. It sounds though like your looking for something like cache manager… Brett :cool:

We are going to purchase a SAN system. I’m a very new DBA (got the junior in my title <img src=’/community/emoticons/emotion-1.gif’ alt=’

‘ /> ), and I’m being asked to come up with the best configuration for our databases (why me? I’m still a JR DBA!!). I don’t know where to begin!! I’ve been reading up on RAID levels and think RAID10 seems to be a good choice for our data files and RAID1 for my log files, of course no testing has been done yet to confirm this. We have a production server that is of course OLTP (18 GB), and data is replicated to our Reporting server on a 10 minute frequency (this one is 120 GB). Can someone please help me, just point me to the right direction. I feel like a tiny fish in the big ocean right now..don’t where which direction to swim to.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by x002548 Now that is a lazy dba… :cool:

<hr height="1" noshade id="quote"></blockquote id="quote"> Ok open up System Monitor>right click on the graph>click add counters>Select Object (My guess SQL Server<img src=’/community/emoticons/emotion-2.gif’ alt=’

‘ />atabase/Memory Manager/Buffer Manager/Physical disk etc.)>Select the counter you want to monitor>Close the dialog box. I don’t think that is giving someone direction, it’s more like spoon feeding. However we were all there at one point in our careers actually I am still in a learning phase with SQL Server coming from a sybase background. Tsusanto, you shouldn’t get yourself pressured and stressed out, being a DBA is a big responsiblity, just take things by steps. The reason I pointed you to BOL is because there you will find lots of information on what you are trying to do. You were not very clear with your question so maybe reading BOL would give you some direction on what exactly you were trying to monitor. Anyways good luck and read, read, read.

Thanks for your advice Lazy_DBA. I have been reading BOL a lot and also reading the articles on this forum.
I ran performance monitor and chose
Disk Read Bytes/sec
Disk Reads/sec
Disk Write Bytes/sec
Disk Writes/sec
Buffer cache hit ratio
Transactions/sec Ran it for 2 hrs at 15 seconds interval and came back with an average of 153 reads/sec and 33 writes/sec. That means the read:write ratio is abt 5:1.
Would this qualify as a OLTP? I would expect higher write ratio it it was really an OLTP. Also, what would be considered normal for disk read bytes/sec. If my system reads an average of 8 MB/sec, is that too heavy on I/O?

What you want is high buffer cache hit ratio readings close to 99% and lower Disk Reads. How much Physical RAM do you have on your server?

My buffer cache hit ratio is good. It’s about 97% for that 2 hour window, which is our peak traffic time.
We have a active/passive cluster using Legato Co-Standby Server 2000 and we had a problem a while ago and restarted the active machine so Legato failed over to the passive machine.
After that, our Disk Read Bytes/sec went up to 8MB/sec. Before, when the other machine was the active server, it used to be around 3MB/sec. It’s an identical machine and we don’t know what’s wrong witht he high disk read bytes/sec we have now. We have 8GB of RAM.

Capture counters Physical Disk: % Disk Time & Avg. Disk Queue Length to further assessment.
Ensure all other related services are started and working without any issues by referring to the windows event log & SQL server error log.
HTH Satya SKJ
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