A Response to Barry Burke, The Storage Anarchist
by Claus Mikkelsen on May 29, 2009
I’ve been bouncing around various blogs in the past few days answering questions on the HDS announcement from last Wednesday: The Hitachi High Availability Manager (HHAM, HAM, AM, call it whatever you want and make any jokes you wish). Like any announce, we try to keep things fairly high level, since in a 20-minute webcast, we’re not going to be discussing how we deal with world wide names, port assignments, and the like. We roll out the details later and as the questions come in. This is standard procedure for any technical announcement from any company.
In the past 3 days (today included), we’ve fielded questions, had many dozens of conference calls, spoken to the media, financial analysts, and industry analysts. It’s been a fun few days, and the interest is very high, but I would like to emphasize that in fielding these questions and interest, customers top the list as does any analyst representing customers. Somewhere further down on that list are the questions that come from our competition: EMC and IBM. It’s not that there’s no love here, it’s just a basic priority thing (‘scuse me Mr. ReallyBigBank customer, I’ll get back to you tomorrow after I answer EMC’s questions, first).
Barry’s post the other day took exception to our less than prompt answers to his good questions. They are good, and I will answer them here, although I suspect the motivation is pot stirring and information gathering to fuel the expected FUD machines. I’ll ignore his dripping sarcasm and vitriol and get to the basics of his questions. Really, you should all read his post!
But if Barry would allow, and to compensate for the above, I have to have a little fun first. Barry’s post on this started out by saying: “…I hate to be a pest, …” which got me thinking that since this whole HDS announcement started with an anagram, I could anagram “STORAGE ANARCHIST” into “’TIS A STRANGE ROACH”. (Sorry, Barry, but I couldn’t resist!!)
But onto the questions:
• Q: Why didn’t you include the GA date in the announcement? Are you hiding something? A: Yes, we are trying to conceal the GA date and you have no idea how much trouble I’ve gotten into by saying over and over that it’s 4Q this year. Why wasn’t it in the formal announce? I dunno, I don’t write those, but the information is all over the place.
• Q: Are there really NO host requirements? A: I may have misled here. What I’m saying is that there are no additional host requirements since I’ll assume path failover software is pretty standard these days. Initially we’ll support HDLM and perhaps others by GA.
• Q: How does a host know to start sending I/O’s to a different target? A: Path failover that supports HHAM will have owner-paths and non-owner paths after all owner-paths fail then path failover accesses the non-owner paths which are on the secondary controller. I would think you could have guessed that!
• Q: And exactly how does consistency and compliance work when TSM can’t relocate a volume that is being replicated? A: Consistency is maintained by TrueCopy Sync. HAM takes another pre-caution by checking the Quorum disk before a failover to insure that the pair(s) in question haven’t been suspended.
• Q: Oh, and please – you are the undeniable expert in all things IBM mainframe. Are you suggesting that Hyperswap is the solution to tech refresh migrations for CKD devices? A: Nope, I’m not. I’m just suggesting that the functions are similar in the sense that it can swap devices, and as you know, the similarity stops there. Hyperswap is an OS function, to begin with.