Dynamic Network Factory Inc. (DNF) announced Tuesday that it plans
to make 120 GB
SATA and SAS drives available with
high-speed RAM attached within its storage products, with the
goal of speeding performance and reducing power consumption.
DNF claims that its Hyper Solid-State hybrid SATA or SAS drives
each pack 20 times more performance than comparable 15,000 rpm
drives. Power consumption, also, is 12.5W, which DNF says is 16%
less power than 146 GB 15,000 rpm SAS disks, and 24% less than
15,000 rpm
Fibre Channel drives.
The drives combine a 2.5-inch form-factor disk with the memory
chip but the drives can fit into a 3.5-inch form-factor drive bay
for compatibility with existing product lines. The drives will be
made available early next week in all of DNF's storage products,
which include the following: FlexStor-NAS Windows Storage Server
NAS appliances; StorBank-XL and DataStor Linux-based NAS;
DAS arrays based on SATA; entry-level Fibre
Channel SAN storage arrays; IPBank IP SANs; and virtual tape
libraries (VTL).
The drives, which cost $2,500 each, could be a much lower cost
alternative to solid-state disks, which are comprised solely of
memory and offer far less capacity than the hybrid version, said
Jame Ervin, technical accounts manager at DNF.
"We had previously offered solid-state drives with our Flextor
SSD NAS products," Ervin said. The solid-state disks were only
available in 8 GB, 16 GB and 32 GB at a cost of $250 per gigabyte.
"It wasn't affordable for a lot of our customers." Ervin added that
the hybrid drives could be used to create tiers of storage within a
box, with traditional SATA drives making up the bulk of capacity
and the hybrid drives forming a Tier-1 layer for a transactional
database or other performance-intensive application.
One area in which DNF cautions that the hybrid drives are
probably not best suited is in IP SANs. "There's a tendency, if you
get a lot of high-performance drives in an IP network, especially
one that's not dedicated to storage, for the network overhead to
negate the benefits of the drives," Ervin said.
Traditionally, storage platforms use RAM cache all in one place,
usually at the controller. DNF says that its storage boxes will
still also use centralized cache, but use the memory on the disks
to further boost performance. DNF also claims that one of the chief
benefits of splitting memory up among drives is that each drive
will also have its own battery, making for better redundancy.
It's a claim disputed by at least one competitor. "It's great
for speeding up [Windows] Vista, but as a write-back cache it seems
a little questionable," said Tom Treadway, chief technology officer
(CTO) of the storage software group at Adaptec Inc. "Our OEMs have
always hated batteries -- you have to make sure they're charged
before using them. And you have to deal with lifecycle issue, like
batteries no longer holding a full charge, needing to be replaced
every few years and then disposing of those batteries. And then
there's the issue of unclean shutdowns where the write-back cache
doesn't match the drives present at the next boot."
In response, Ervin said that customers have been asking for
battery backups on the RAID cache.
"Most appliances don't pursue IO optimization or tuning at the
drive or media level," said Brad O'Neill, senior analyst with the
Taneja Group. "Any time you move away from the industry's de facto
standard, you have a hurdle with customers -- the advantages have
to significantly outweigh the customer's fear of moving off what's
accepted."
Still, O'Neill pointed out, Copan Systems Inc. has had success
with another unorthodox approach to SATA in
MAID." Absolutely, it can happen," O'Neill
said.
Several other companies are currently working on hybrid
technologies, including consortiums of drive makers headed up by
Seagate Technologies Inc. and Fujitsu Corp., as well as another
group fronted by IBM that is looking to replace drives and memory
altogether. So far, the other drive makers are focusing hybrid
efforts on the consumer space, particularly in laptop PCs.