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08/17/2009

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This was a great topic to cover and you described it well in laymans terms. Don't know what you have plans to cover in the future, but here are a couple of topics that I would love to hear you expound on as you did with the above explanation of SLS:

- The advantages of subsystem and job control (i.e. WRKACTJOB and all of it's options)

- The advantages of library lists and call stacks.

- The advantages of having the DB embedded into the OS.

Thanks for taking the time to help us prove that IBM i is the best darn OS in existence.

SSDs are a hot topic for sure. If you would like to learn more there is a webcast on October 6 through System i Network where we will discuss the value of SSDs and take your questions.

To register for the webcast see: https://event.on24.com/eventRegistration/EventLobbyServlet?target=registration.jsp&eventid=159213&sessionid=1&key=EE2FA729056EEFB2A2F0A6BBD4844C84&partnerref=wbcsthmpg&sourcepage=register

I've been working on IBM i systems for two years and I've been asking myself if the SLS architecture was something good or bad since the first time I've heard about it (I don't like very much the idea of not being able to exactly understand where my data are, but it's just a personal opinion).. there are always PROs and CONs, but I liked very much your post Steve..

Just one question about the SSDs... we are using external DS8100 storage systems for our IBM i v5.4 partitions: will we be able to introduce some SSDs on our DS8100s, along with the already installed HDDs, or DS8100 won't support mixed SSDs and standard HDDs in the same machine? If it is possible to install, for example, only and array of SSDs in a DS8100, will the IBM i be able to recognize which logical LUNs of the DS8100 are spread on SSDs or will it simply see DS8100 LUNs without being able to understand on which disks they effectively are?

Hi Gianni.... yes SSDs are supported with the DS8100. Best practice would be to have a LUN full of SSDs. Regarding IBM i support, the explotation of SSDs that Steve discussed works with internal SSDs today. We plan to extend this support to SANs and VIOS attached SSDs later on in 2009. This extension will be with an update to IBM i 6.1. So bottom line, yes we will be able to support the environment you described with IBM i 6.1.

Gianni - Craig answered your question, so that's taken care of.

Aaron - thanks for the ideas for future topics. Have you been reading my mind? (Or placing thoughts there?) That's the sort of thing I was imagining - a series of articles that helps answer the "Why i?" question.

Mark (sent me an e-mail, but I thought the reply would help others too) -
The tools mentioned above are Start ASP Trace (strasptrc) and Start ASP Balance (straspbal). They have been available for many releases, but the use of them to work with SSDs just started when the support for SSDs came out.

The documentation for using these commands is in the Information Center at http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/index.jsp?topic=/rzarm/rzarmtrace-ballance.htm

One thing you need to be aware of to make use of them with SSDs is that we've had to overload the existing "*HSM" value to work on SSDs. This will be changed when the next major release comes out.

Hi Steve,

Very Good Post!

Can you give some light on "the operating system manages the placement of data on storage"
I don't I am correct but all the OS does the same. Then how can say this is an unique feature of IBM i?

Warm Regards,
Maran

Another possible topic to expound on is whether the IBM i operating system uses memory more effectively/efficiently than other operating systems and thus doesn't need as much as a Windows/Linux machine to facilitate the same number of users/processes.

Maran asked this:

"Can you give some light on 'the operating system manages the placement of data on storage' I don't I am correct but all the OS does the same. Then how can say this is an unique feature of IBM i?"

The key to IBM i, and its predecessors, is that it transparently manages all data across all the storage it owns, without requiring customers to know (or typically care) about which data is stored on which physical drive.

True, each OS puts data on the storage device. However, in most other OSes, the customer or application must choose which storage device gets which data. Customers have to get involved in balancing data across their multiple drives (or volumes.)

If you search the web for "data balance across disk" and you put the name of an operating system in front of that, you'll find that there are many complex documents and tools that teach the users of other OSes how to manage data across storage devices.

For IBM i (i5/OS) you find articles that tell you that IBM i does it for you. The trace/rebalance step is very simple, and does not require the customer to know the placement of the data on the devices.

I hope this helps.

Thanks a lot Steve!

Now I have gotten how IBM i differs from other OSes in terms of Storage Management

Thanks Again!

Maran

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