Scaling the SAS learning curve

20.10.2005
Von Mario Apicella

Aside from the SNW Fall and the Storage Decisions conferences I mentioned last week, another major October storage show opened its doors this month: the London-based Storage Expo. For U.S-based storage mavens, it"s a show worth visiting because many storage vendors rehearse demos of new products there before an official launch in the States.

I missed the show this year, but a few vendors kept me fed with news from across the pond, and it was certainly interesting. For example, all Penguin enthusiasts should know that Broadcom was showing off a new PCIe (PCI Express) RAID controller supporting both SATA and SAS (serial attached SCSI) drives, running on a Linux server.

Broadcom"s announcement joins a long spiel of news focused on SAS, the new reincarnation of SCSI, and came only days before Adaptec unleashed a small torrent of new SAS products, including HBAs, RAID controllers, and disk enclosures.

"We have been shipping SAS products to other vendors for a long time," says Tim Connolly, vice president of Adaptec Data Protection Solutions Group, mentioning IBM as an example of one of those "other vendors." However, the products in these particular SAS announcements target not only other vendors but also large-enterprise and small-business customers.

Take, for example, the US$360 eight-port 48300, a PCI-X HBA that mounts one external and one internal four-device connector. In plain English, with this HBA your high-end desktop can mount as many as four SAS or SATA drives inside and connect four more from an outside box.

Don"t feel bad if that "one external and one internal four-device connector" sounds like a riddle, because we all need to learn new tricks with SAS. Here"s some help from Adaptec in the form of a poster explaining common SAS connectivity that you can download as a PDF file -- or have a paper copy shipped to you (shipping is free, but requires registration).

Turning back to the 48300, you can implement software RAID 0, 1, and 10 or address each drive individually -- and it runs on most major OSes, except for Unix (at least for now).

Need more enterprise-class punch for your servers? The PCI-X 4800 or the PCIe 4805 offer fully featured, hardware-based RAID for eight internal (or four internal plus four external) SAS/SATA drives.

The price is higher, at $945 for the PCI-X and $995 for the PCIe, but the two cards offer some interesting features, including array capacity of as much as 512GB, the ability to change a LUN (logical unit number) capacity or RAID level online and to make full use of disks with different capacities, and the ability to create multiple LUNs on the same drives.

By purchasing the Advanced Data Protection Suite (price to be announced by the end of the year), you can add more jaw-dropping features to those two cards, such as RAID 6, which enables survival of two consecutive disk failures, online backup to disk or tape of volume snapshots, and access distribution across spare drives.

Last, but not least, in the Adaptec SAS pyrotechnics show are its new storage enclosures. The 335, ideal for the home or for a small business, is capable of hosting four SAS/SATA drives and attaches to any of the controllers I mentioned previously. (Remember that mysterious "external four-device connector?")

At $369, the 335 enclosure doesn"t require a big investment, but you"ll have to buy your own drives. If necessary, it can also mount a slim-IDE (integrated drive electronics) CD-ROM drive.

Sounds like something you would love to find under your Christmas tree this year, doesn"t it? Although when you add, for example, four large-capacity SATA drives and a 48300 HBA, it becomes a slightly more expensive present.

As for the enterprise landscape, if your server capacity is bursting at the seams, for about $6,000 you can buy Adaptec"s SANbloc 5000f, a 2U, 12-drive RAID enclosure that connects easily to your FC (Fibre Channel) SAN, and can chain together as many as eight units.

Haven"t seen this baby in action yet, but after you buy your own drives, expect to manage all enclosure from a single management console and to find all the RAID capabilities mentioned before, plus support for features such as MPI/O (multipath input/output); SMI-S, the SNIA-promoted management standard; and VDS (Virtual Disk Service), the Microsoft equalizer for heterogeneous devices.

If RAID and all these other goodies are overkill for your application, consider the SANbloc S50 JBOD instead. The S50 JBOD is a disk enclosure that can expand to the same 54TB capacity as its 5000f sibling for half the price.

If your head is spinning after taking in Adaptec"s SAS deluge, welcome to the club. Adaptec must have anticipated that customers (and reporters) would need to absorb a lot more than just the new cabling of this new fascinating replacement for old SCSI, and they have created a Weblog manned by Adaptec engineers to answer your questions about SAS. You"ll find the blog at http://storageadvisors.adaptec.com.

Creating this technical support blog seems a very smart way to start a new technology wave and should help fill customers" knowledge gaps quickly. Hopefully, other vendors will take note and do the same for other new storage technologies.

Join me on The Storage Network blog to discuss this and other topics.