By Timothy Prickett Morgan
IBM Corp’s San Jose-based storage subsidiary is just days away from unveiling the Shark follow-on to its Tarpon Versatile Storage Server. As far as anyone can tell, the Shark array, which will be sold as the Enterprise Storage Server, uses hardware that looks very much like that in the Tarpon array. The Tarpon consisted of two RS/6000 H50 motherboards coupled together to create a redundant array controller that controlled racks of RAID-5 disk arrays. These H50 motherboards use four of IBM’s 32- bit PowerPC 604e processors and can support up to 3Gb of main memory, which is used as disk cache memory in the Tarpon array. The Tarpon could wrap around existing RS/6000 7133 SSA RAID 5 arrays, which used 4.5Gb and 9Gb disks, or come equipped with whole new racks of similar disks. Tarpon supported most popular Unix variants (with SCO UnixWare notably absent from the list) as well as Windows NT and OS/400, the AS/400’s operating system. It could have up to 16 concurrent (and different) hosts, each with a different data partition on the array. Shark is the same basic hardware, only the disk drives have been upgraded to IBM’s more recent 18Gb and 36Gb units. According to rumors we’ve heard, the base Shark array will have 420Gb of storage using 9Gb disks, which will be called the 2110 model E10 array. A model E20 array will reportedly use 18Gb disks and have double the rack capacity. Customers who need even more data storage can shift to 36Gb disks or add more 7133 racks. The maximum total storage on the Shark will apparently be over 11Tb, which IBM will accomplish by moving to 72Gb disks sometime next year.
Shark will initially support both open UltraSCSI and proprietary ESCON mainframe attachment schemes. Some time in the future, perhaps in the first quarter of next year, IBM will add support for Fibre Channel attachments and its mainframe variant of that standard, which it calls FICON. Shark will also apparently have 384Mb of non-volatile cache memory to back up those dual 3Gb memory banks in the controller. The word we hear is that while Tarpon could support 16 host servers, Shark will be able to handle 32 hosts. No one knows if SCO support will be added with Shark, but given the fact that SCO is IBM’s remaining Monterey/64 development partner now that it has eaten Sequent Computer Systems, odds are IBM and SCO are working on drivers now if they haven’t got them finished already.
If the hardware in Shark is not all that different from Tarpon, the software certainly will be. Shark is the disk array that IBM should have announced five years ago if the description we’re hearing is correct. If customers were wondering why a rack of 7133s needed two quad RS/6000 boards to act as a controller, now they know why. Shark is going to be loaded down with lots of software functionality so it can compete against disks from market leader EMC Corp. The details are a bit sketchy on exactly what functionality will be in the Shark, and on what platforms it will initially be delivered on. But the word seems to be that IBM will bring a lot of the functions that are in StorageTek and EMC mainframe-class arrays to open systems, NT and OS/400 as well as – finally – to mainframe customers. EMC has been giving IBM a very hard time in the mainframe market because its open systems arrays, the Tarpons, were announced without support for S/390 mainframes last June. (EMC was giving IBM an even harder time before Tarpon was here. Its Symmetrix arrays have supported simultaneous attachment of mainframe, AS/400, Unix and NT servers for years.)
Here’s what the word is, and we have no confirmation from IBM that these software functions and their descriptions are correct. The Sharks will apparently have some functions that will only be available for OS/390 and MVS. One is called Extended Remote Copy, which will be an implementation of the Remote Copy function in its existing RAMAC mainframe arrays. Another is called Concurrent Copy, which may allow data sets to be copied to multiple mirrored arrays at the same time. The SnapShot feature of StorageTek’s RAMAC Virtual Arrays (formerly known as Icebergs before IBM started selling them under its own label) will not be put into Shark. But very similar functions will be in Shark, and they supposedly will be available to all types of servers attached to the Shark array, not just mainframes. One such feature is called Flash Copy, which creates a copy of a disk volume in the memory of the Shark controller or in the main memory of the server it is attached to (no one seems to know which one) to speed up data access for batch and online transaction processing jobs. Another feature called Peer-to-Peer Remote Copy will allow Sharks attached to any kind of server to mirror each other from as far away as 60 miles. The Parallel Access Volume feature lets the Shark array clone popular disk volumes and spread the data requests across those clones. It apparently does this automatically and transparently to the applications making use of the data. Yet another feature of Shark is Multiple Allegiance, which will let multiple servers with the same data formats and operating systems share one copy of the data in a Shark data partition.
Meantime, this week’s Wall Street gossip had it that IBM may buy its one-time partner Storage Technology Corp as it attempts to build a leading multi-platform enterprise storage business. Industry watchers discounted the rumors, suggesting there are now too many overlapping products. Four, or even two years ago when StorageTek was supplying IBM with its mainframe arrays such an acquisition would have made sense, they said.
