by Zsolt
Kerekes, editor, StorageSearch.com
- May 21, 2012
A new family is planning to move into the
enterprise end of SSD
street - removable 2.5" SSDs which have a PCIe interface.
You
can expect all enterprise PCIe
SSD makers and most makers of
SAS SSDs to be in this
market with announcements, demonstrations or shipments by the close of 2013.
The
only complicating factors which are going to slow down the race to get products
into the 2.5" PCIe SSD market are detailed marketing decisions about
whether to ship vanilla SSDs or use the new form factor as a way to leverage new
features which users will specifically value or expect too see in this
particular module form factor - due to the cultural heritage and experience with
earlier types of 2.5" SSDs. They relate to:-
- SSD software:-
the specific type of virtuualization. The 2.5" paradigm supports hot swap
and upgrades. Ideally the software should support almost instant benefits if
users decide to plug in new 2.5" SSDs.
- standards: - what
language will the 2.5" PCIe SSDs speak? PCIe is a neutral physical
connection. The emerging SCSI Express standard is just one of many
possibilities. Others include standard storage networks such as
SAN,
iSCSI etc.
- fault
tolerance:- what type of architecture will underpin the 2.5" PCIe SSD
rack? Possibilities range from standard
RAID like systems upto
proprietary schemes which can provide much better resilience at greater
efficiency.
- pricing strategy:-
the new form factor will open up new application slots - some of which will be
positioned above those of existing 2.5" SAS SSDs. But less obviously by
negating the essential need for on-board controllers some of the new SSDs
could be positioned in the cost gap between high end enterprise SATA SSDs
and fast-enough SAS SSDs too (see more below).
How will the 2.5" PCIe SSD market affect the business of current
PCIe SSD companies?
I've spoken to a representative sample of
enterprise SSD companies about the new form factor. This includes companies
which currently make PCIe SSDs and also some who don't.
The general
view is that 2.5" PCIe SSDs represent additional new business - compared to
installing PCIe SSD cards and multi-card modules into server slots.
How
will 2.5" PCIe SSDs impact the business of SAS SSD makers?
In
the long term I think it will reduce the market size for SAS SSDs because the
new types of SSDs will provide faster throughput and lower latency - and the
possibility of offering fast-enough SSDs at lower cost too.
However SAS
SSDs work here and now - and it could take another year or so for 2.5" PCIe
SSDs to get firmly established in the market.
My guess is that
initially some vendors of 2.5" PCIe SSDs will position their products as
options which sit above the performance capabilities of their SAS SSD product
lines.
But other options are possible too. For example a 2.5" PCIe
SSD - which offloads its flash controller functions to the host server (like
Fusion-io's products)
could deliver lower power consumption and higher capacity than traditional SAS
SSDs - and at lower cost. In the non-offfloaded flash management design (which
other vendors may also introduce too) - the new 2.5" PCIe SSDs could be
designed at a lower cost than SAS SSDs (because they don't need the controller).
That's one of the reasons that SAS SSD makers are looking at this
market too.
Why do we need yet another type of SSD component in the
enterprise?
The simple answer is that some users prefer the unit of
upgrade or fault replacement to be a drive instead of a whole rack.
And
although it's possible to upgrade or replace PCIe SSDs at the card level - it's
more convenient to do so at the module level.
The new 2.5" PCIe
SSDs will affect the variety of options seen inside fast SSD racks. They have
been a long time coming and are already included in my earlier published models
about SSD market silos.
As I said above - there will soon be more than
20 companies in this market - and the new products will be the showcases for
new configuation possibilities.
Companies which have already publicly
announced such products and demonstrated prototypes include:-
OCZ,
Micron and
Fusion-io.
...Later updates:- September 2012
The subject of 2.5"
PCIe SSDs and related standards such as NVMe came up in several papers and blogs
centered on the Flash Memory Summit
(August 2012).
Here are some links and notes.
- "2 competing enterprise initiatives have emerged in the attempt to
align the industry around PCIe based SSDs - SCSI express (led by HP) and NVMe
(led by Intel and Dell). While a 3rd standard - SATA express - is aimed at
clients and hybrids. In the 2.5" drive size - a multi-function bay can
support both SAS and PCIe SSDs with the same SFF-8639 connector" -
HGST
paper - enterprise interface trends (pdf)
| |
..... |
| ..... |
|
|
|
|
| ..... |
|
|
|
| |
 |
There's something
subtly
different about
enterprise drives. | |
| .. |
 |
... |
product concept
inside the 2.5"
PCIe SSD
image supplied for this article by
OCZ | |
| . |
|
|
| . |
|
|
| . |
|
|
| . |
|
|
| . |
 |
| . |
| "I can see no
advantages or reasons to start using PCIe SSDs instead of SAS SSDs inside our
systems....." |
| Thomas Isakovich,
CEO and founder of Nimbus
replying to a question from the editor of StorageSearch.com about the
technology roadmap in their rackmount SSDs - (February 2012) | | |
| . |
 |
| . |
| don't all PCIe SSDs
look pretty much the same? |
When you look at the
photos and headline specs for high speed PCIe SSDs - it's easy to come away with
the impression that they all look the same and have about the same performance.
After
all - how different can they be?
But don't let the experience of the
2.5" SSD market -
in which clusters of consumer SSD vendors use the
same or similar
controllers and hover
close together inpopular
(consumer) performance rankings - give you the wrong idea about
PCIe SSDs.
In
this market the performance limits and capabilities of the SSD aren't set by an
old hard disk interface
and package limitations.
In the PCIe market the products you get are
limited only by the imagination of the designers - tempered by the guesses of
marketers who are trying to predict the optimum (most salable) features for an
ideal SSD. |
|
| | |
| . |
| How are
fault tolerant PCIe SSD designs supported in chips? |
| PCIe in
enterprise SSD designs - this video by PLX includes an
introductory tutorial into PCIe and its performance and architectural
capabilities for SSDs including automatic failover and multi-host capabilities. |
| PLX's switch chips also supports failover if
the fault occurs in the PCIe switch fabric chips themselves. |
... |
|
extract - "...And in case one of the hosts fails
and you want to connect the SSDs - or the devices connected to that host - to
another host - that can be done automatically as well - and the surviving host
can attach the devices that were attached to the failing host to itself and
control it so that the system doesn't go down and the data stored in these
devices doesn't get isolated from the main system." | | | |
| . |
| |
