Any experience with SLA's in a Storage Environment?

[Sudhir Gadepalli]

Just reaching out to members to see if anyone has defined and/or implemented SAN related SLA's - examples may include things like how storage allocation is performed, what the performance criteria are, what the service level requirements dictate, how compliance is measured and what type of reports your customers/end users/consumers of storage typically demand...please share your experiences.

TIA.
_Sudhir

[Gerard Bonin]

Sudhir,

We implemented a SLA for SAN performance for our Exchange database servers. This is a very small amount of our overall SAN storage. It was done to provide us with a way to make the Exchange admins feel comfortable with the Exchange databases coexisting on a shared SAN. Previously, they had been on a dedicated SAN, so they were concerned about performance and wanted to stay on dedicated hardare. They provided us with their list of metrics for monitoring and their thresholds. We implemented the data collection and reporting. It has been working well for several years and the shared SAN is rarely considered as a cause of Exchange slowness any more.

The important part was getting them to provide the metrics and thresholds. They used Microsoft's guidelines, so they felt comfortable and the daily/weekly/monthly reports let them know that things are still fine. These same reports are also reviewed by the storage admins.

It took a fair amount of time to implement this and takes more time occasionally to accomodate changes to the Exchange environment (new servers, new file systems) but it was well worth it.

Gerry

[Cathy Nolan]

Some organizations focus more on capacity than they do on performance so SLAs aren't always easy to establish and/or track, especially in a SAN environment. Additionally, depending on the complexity/size of the SAN environment, organizations can use a pretty broad rule of thumb when deploying storage - for example monolithic storage is deployed for those applications that need high performance and high availability, and modular/NAS storage is deployed for all other applications. SLAs can be key for database environments, but I haven't seen them broadly implemented for every application/level in a SAN storage environment.