ILM Revisited: Intelligent Tiered Storage for File and Content Data
by Hu Yoshida on Sep 28, 2009
I am taking a break from the blogging wars over virtualization to plug a Webcast that I will be doing on The economic Benefits of Intelligent File Tiering. It will be on Wednesday, September 30 from 9:00 am to 10:00 am. You can go to this website to register.
If you remember about 5 years ago, ILM, Information Life Cycle management was all the rage. ILM was the ” policies, processes, practices, and tools used to align the business value of information with the most appropriate and cost effective IT infrastructure from the time information is conceived through its final disposition. ”
At that time SANs had been well adopted and lower cost storage like SATA was becoming available. Storage vendors were rushing to define their solutions for ILM. Some vendors were extolling the benefits of moving data up and down tiers of storage based on changing business requirements. While ILM was a good idea, the technology was not there to implement this idea without a lot of extra work.
The tiers of storage were static. While there was cost differentiation between types of storage and there was SAN connectivity, there was no dynamic capability to move data between tiers. Even if the tiers of storage resided in the same storage frames, you had to move the data between tiers with software, which meant disruption to the application. Non-disruptive movement of data between tiers of storage requires storage virtualization. Hitachi with the USP V and yes, IBM SVC , can do non disruptive movement of data, in volumes, between tiers of storage.
However, volume movement of data can mean a lot of heavy lifting. Volumes are getting larger and moving a TB volume across tiers of storage is not something you want to do on a frequent basis. As a result you may assign a volume to an intermediate tier and promote it only if it needs more performance or demote it if it doesn’t. The more likely use of dynamic tiered storage volumes is to create copies to lower cost tiers for offline processing like data mining, or development test.
Tiering with files is easier to do. Today it can be combined with block tiers and Content Archives and comes closer to the vision of ILM. One can define a file system across different tiers of storage and Hitachi’s HNAS can move a file in a file share across the tiers using policies based on POSIX information. For instance if the file is an MP3 file HNAS could move it to the lowest cost storage or delete it.
It can also be stubbed out of the file share and pushed to an HCAP content platform where it can be injested, indexed and stored for long term retention. HNAS could set a policy to move all PDFs older than 60 days and containing the word “budget” to HCAP and let HCAP manage the lifecycle of this file. If HNAS needs to retrieve it, it just pulls it up via the stub. When the file share is backed up, no resources are spent on the file that was stubbed to HCAP.
Dedupe is a great tool for reducing the backup load, but dedupe is really addressing the symptom and not the cause. The cause is stale data that we backup over and over again. If we stub the stale data out to HCAP, we address the cause, which is stale data. As long as we maintain two HCAP copies of data, there is no need to back up the data that resides in HCAP.
If you want to hear more, please tune into the webcast on Wednesday, September 30, from 9am to 10 am. The Economic Benefits of Intelligent File Tiering