disk actvity on san

Last Post 14 Feb 2007 05:05 AM by TRACEYSQL. 2 Replies.
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TRACEYSQL
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08 Feb 2007 01:50 PM
i was reading about fn_virtualstats and it is since the server sql has been rebooted..
is there a way to figure out how many bytes of data is being sent over the network to the SAN and how long it is taking......i see disk length is high but i want to do measurements on this

Any advice is greatly appreciated.

I not sure if our san are powerful enough and want to measure this.
drivkind
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10 Feb 2007 11:37 AM
There are so many things to consider in a SAN environment. Are you using a fiber or iSCSI connection? If it’s fiber, what topology was implemented in the fiber switch? What’s the RAID configuration, how many other systems are accessing the same controllers/disks, how many controllers vs how many disks, what types of disks?

A SAN typically has other systems besides SQL Server which contribute to I/O activity or bandwidth limitations over the fiber/iSCSI channel. If you want to measure the bandwidth of your fiber or iSCSI channel, there are is which can do this. Block Storage Tester (BST), such as Spirent SmartBits, will measure all sorts of things, but you’ll pay roughly $4000 for the software. There's also a good chance the management software included with the SAN has a tool to do this.

If you're having performance issues, there's a range of possibilities. So much of it comes down to the initial setup in hardware and configuration.

First, I would look in Windows performance monitor to check the basics, like disk I/O read/write and waits/queue length, memory, and SQL Buffer Manager to see if you can get an idea of where the bottleneck is.

If you have some other questions, it will be easier if you can provide more information on your SAN configuration, your environment, and any specifics on the performance issues.


- Dana Rivkind




TRACEYSQL
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14 Feb 2007 05:05 AM
Thanks very much i am going to start with the Permon and see what i get.

From pervious test the disk queue length is always high

I do some test and let you know...
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