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Solid State Disk
(SSD)
What
is a solid state disk?
What
can SSD do for a system that regular disks cannot?
Why
not just add more server memory?
What makes SSD safe for critical files?
What are the benefits
of installing MegaRam?
What are some examples of time critical
applications?
Are
there any specific examples available showing actual
performance gains seen by users?
How do you install a
MegaRam?
How do I know what files
to move onto solid state disk, SSD?
Are there any tools or
utilities to help the customer identify hot files?
Are there applications
other than relational databases, etc., that benefit from SSD?
Are there
companies
using this technology now?
Can I mix and match interfaces on the MegaRam?
How do I know the MegaRam will work in my SAN?
What kind of management tools are available?
Can the MegaRam-35 be built into a server?
Why do I need a SSD when I have a cached array (RAID)?
Is your Fibre Channel native or a bridged implementation?
What software companies have you
partnered with?
What
is Solid State Disk?
A solid state disk (SSD) is a storage accelerator that attaches
to a server just like a standard magnetic
rotating disk. However, SSD stores data in DRAM, the same type
of semiconductor devices used to make main memory for the CPU,
not on a rotating platter with a magnetic coating. This memory
is approximately 200 faster than a disk drive.<TOP
OF PAGE>
What
can SSD do for a system that regular disks cannot?
SSD delivers thousands of I/Os per second compared to a
standard 15,000 rpm disk's I/O rate of about 125 per second. This
dramatic performance increase is possible because SSD technology has no
mechanical latency. Unlike a hard disk, there are no heads to
be positioned and no magnetic disk platters to rotate.
Why
not just add more server memory?
Adding main memory in
the server may not be a better alternative due to:
1.)
Potential Data Loss: If for any reason power to the server fails, the
data in memory cannot be recovered. This is one
reason relational databases such as Oracle
and
Sybase have the ability to do their own I/O, so the operating
system can not cache this data in memory.
Some critical files
such as logs, are non-recoverable. These files have slightly different names depending on the particular
database being used, such as redo logs, transactional logs,
physical logs, logical logs, etc.
2.) Caching files in server
memory consumes memory space that may be needed for general system
operation. In multi-user systems setting up caching space to
service an application can cause other users to see significantly poorer system
performance.<TOP O
3.) Server lives tend to be
very limited as CPU performance changes frequently. Many
times this server memory cannot be migrated to the new
server platform.
What
makes SSD safe for critical files?
Imperial's solid state disks have a built-in Uninterrupted
Power Supply (UPS) that provides continuous power to the
unit if primary system power fails. The SSD even does periodic
self-testing to make sure its UPS is ready and able to
handle a power outage. Some systems also feature a redundant
UPS option for even higher redundancy.
This UPS system includes a rotating disk to automatically
receive a copy of all the data when power fails. Whether the
power failure lasts only a few minutes, or is one that occurs
during a long holiday weekend when the system is unattended,
all the data is safe. When power is restored the data is
automatically restored to the primary DRAM storage.
MegaRam solid state disks
feature powerful
proprietary multi-byte error detection and correction (EDAC)
capability that can
detect and correct up to 6 full bytes of data rather
than a Hamming code that performs single-bit error correction
as in server memory.
What are
the benefits of installing a MegaRam SSD?
If your environment is I/O bound, you will notice a number of
immediate benefits:
- Better
response to queries
- Faster
running batch jobs
- Applications running faster
- More
users without performance degradation
- Faster
terminal response for all users
What are some examples of time critical
applications?
There are many, including wireless messaging, online reservation
systems, and process
control.
Stock
and commodity trading requires quick response to rapidly
changing conditions. Automatic buy/sell programs kick-in when
computers analyze data and specific thresholds are reached.
Extra time spent on a slow I/O system before initiating a
trade can have serious financial implications. For more
examples, click
here.F P
Are
there any specific examples available showing actual
performance gains seen by users?
A national hotel reservation system running Informix got 4:1 performance improvement when the trace logs were
put on a MegaRam solid state disk.
An
airline travel reservation company received an 8:1
performance improvement on their Informix application after
placing the hot tablespace and indices on a MegaRam solid state disk.
An
Oracle user running a resource management system got a 6:1
improvement in data reloads and index rebuilds and a 20:1
improvement in query response time.
Click
here to see more users and installed
applications.OP OF
PAGE>
How is a
MegaRam SDD installed?
Quickly and easily, just like adding any another disk to the
server. For direct attached, simply plug into the SCSI or FC ports. No
drivers or special software is needed.
Since
this device is for "hot," very active files it is a
good idea to install it on its own SCSI bus or fibre channel using the fastest
available host bus adapter. By giving this device its own
channel to the computer the system can take full advantage of
its speed. The device can also be installed on a Storage Area
Network (SAN) and supports full
fabric login capabilities.TOP OF PAGE>
How
do I know what files to move onto solid state disk, SSD?
Although there is a good likelihood that the
site DBA will know
which files are the most active, listed below are the names of
files usually moved to solid state disk.
-
DB2:
Log files, Indices, Temp table
-
Informix:
RootDBS table, PHYSDBS, LOGDBS, and TMPDBS1
-
Oracle:
Redo logs, Rollback Segments, and Temporary tables
-
Progress:
AI, BI, and Temporary tables
-
-
Sybase:
Transaction Logs, Tempdb, heavily hit tables
-
SQL:
Heavily hit tables, Transaction logs, and Temporary
tables
-
Are
there any tools or utilities to help the customer identify hot
files?
Yes. There are several tools and utilities
available in or for your operating system.
Unix
has IOSTAT and SAR utilities that indicate which disks are
getting the most activity.
Hewlett
Packard provides a utility called GLANCE in its HPUX operating
system.
Windows
NT has a utility called PERFMON, which supplies similar
information.
Oracle
has a diagnostic utility called Oracle Monitor, which is part
of all Oracle systems. This shows the number of I/Os to the
various files.
Sybase
also offers a monitoring utility but it is an option and,
therefore, not every customer will have it.<TOP
OF PAGE>
Are
there applications other than relational databases that
benefit from SSD?
Yes. MRP, CRM, CAD, finite element analysis, wireless
messaging, process control,
email, and server authentication to name a few. All these
applications benefit from this easy-to-install technology. In
fact, any application that performs a lot of disk accesses
will benefit.<TOP OF
PAGE>
Are
there companies using this technology now?
Solid state disk
technology has a proven record of
improving system performance on super-computers and
mainframes. Companies long familiar with this technology
include Alcatel, AT&T, Boeing, Citibank, Dow Jones,
EarthLink, eBay, Federal Express, Instinet, MBNA, Pacific
Bell, Reuters News Service, Rockwell, and the US Government
just to name a few. <TOP
OF PAGE>
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