RemoteSHADOW® General Product Description:
As a result of major business interruptions caused by man and nature, business managers
have come to understand and measure the consequences that disruptions in access
to data can cause to the business. As a result more businesses are developing and
implementing initiatives to find affordable alternatives to keep their data accessible
24 hours 7 day each week.
RemoteSHADOW by Advanced Systems Concepts, provides business with an easy to implement,
application transparent software solution to ensure your business is continuously
protected, updated and available at a remote contingency site in the event of a
local production site failure. RemoteSHADOW is an affordable host based solution
that protects your data without regard to distance and with no artificial bandwidth
requirements. RemoteSHADOW is available for immediate deployment on Compaq's Tru64
UNIX and OpenVMS.
How does RemoteSHADOW transport information to my site:
RemoteSHADOW provides two highly reliable methods of transmission to a remote site
or system. With Synchronous communication your data is first written at the production
system and then sent to the remote site to be applied to a remote device for later
use. Once it has been written to the remote system your application can continue
and you can be assured of the highest level of availability and integrity. However
to ensure that production continues with minimal performance impact there needs
to be sufficient bandwidth to continuously write I/O's at the remote site and to
receive a positive acknowledgement back at the primary system. When the number of
write I/O's exceed the networks ability to receive a timely acknowledgement from
the remote system the production application is forced to slow down and wait. These
situations, which can be caused by a large number of write I/O's and/or insufficient
bandwidth is unacceptable as the production systems performance levels will be negatively
affected and therefore must be avoided.
When your application experiences an unusually high activity level, RemoteSHADOW's
unique Asynchronous Mode of operation provides continuous availability, locally
and remotely, with no production system slowdowns and without increasing bandwidth
or costs.
When should we use RemoteSHADOW's Asynchronous Mode:
Many systems have peak I/O periods of short duration during the course of a typical
day. Unfortunately many replication solutions require that you purchase bandwidth
for these limited peak periods and have it idle for most of the day. If you would
like to minimize the operational cost of bandwidth to deal with peak periods or
potential latency delays caused by transfers over great distances then RemoteSHADOW's
Asynchronous communication is the answer!
RemoteSHADOW's Asynchronous feature always works to stay fully synchronized with
the production systems. However during peak periods, either expected or unexpected,
RemoteSHADOW manages the "peaks" by ensuring that the write I/O's are applied at
the local side and then sent in time ordered sequence to the remote side. These
I/O's are written within a latency period, measured in seconds, that you decide
your business can "tolerate." This dynamic tolerance can be modified, on an as needed
basis, even during the production day to match bandwidth with peak periods. RemoteSHADOW
will queue these I/O's and apply them, as bandwidth becomes available within your
specified time period.
With RemoteSHADOW's Asynchronous Communication method you can limit bandwidth expense,
while ensuring the integrity of the information and still be prepared to continue
your computing operations in the event of a primary site failure.
How do you know how much bandwidth you will need:
RemoteSHADOW comes with an advanced Data Collection Program that can be installed
on your system(s) to measure the write I/O traffic generated for each disk device
during a typical day(s). It will then provide a bandwidth model that suggests the
appropriate bandwidth that would allow for the optimal choice of synchronization
and bandwidth expense that your business and budget allow.
What happens if the Network fails during production:
RemoteSHADOW's Network Restart facility was designed to protect against the all
too familiar "transient network failure." Too often when networks are interrupted
it causes other replication products to fail out the remote site or cause a split
or partitioned environment. Very often these network failures are for short or relatively
short periods of time. Nonetheless they can cause replicated systems to initiate
unnecessary and lengthy network copies. During these times your business is unnecessarily
exposed if a primary site failure were to occur during a copy operation. RemoteSHADOW
avoids this problem and our customers will back us up! RemoteSHADOW Network Restart
feature can "tolerate" these interruptions by queuing I/O's, in time ordered sequence,
at the local site and then after restarting your network it will apply them and
any current I/O's in the order that they were generated.
RemoteSHADOW's Network Restart feature makes the implementation of disaster recovery
more reliable!
In what operating environments is RemoteSHADOW supported:
RemoteSHADOW is available to protect Compaq's Tru64 Unix and OpenVMS. If your computing
platform is not listed please call for availability.
