ZSL03189-USEN-01
What is Flash
Express?
With the IBM zEnterprise® EC12
(zEC12), IBM is
introducing a new feature,
Flash Express, designed to
help drive System
availability and performance to
even higher levels. Flash
Express is designed to help
reduce latency for
critical paging that might otherwise
impact the availability
and performance of your key
workloads. For paging
flexibility and efficiency, Flash
Express is a compelling
addition to traditional auxiliary
storage.
Now with the zEC12 flash memory
has been
integrated within the
memory hierarchy to provide
even higher levels of
system availability and
performance. Flash Express
is designed to offer
exceptional performance
for paging spikes by
reducing paging latency.
Transitional workload
processing shifts such as
during start of day
processing, changes in
loads, or collection of SVC or
standalone dumps are
examples where paging might
surge. This is where Flash
Express can help!
Flash Express is designed
to improve availability
through improved paging
performance where it
matters most to your
business- like early morning
trading sessions, or
during critical retail shopping
days.
Planning and
Configuring Flash Express
How is Flash Express
Packaged? Flash storage is
integrated on PCI Express
attached RAID10 cards
which fit in the PCIe I/O
expansion drawer. The Flash
Express feature is
packaged as a two card pair and
each card holds 1.4 TB of
memory per mirrored card
pair. Up to four card
pairs may be used concurrently,
delivering up to 5.6 TB of
memory.
Flash memory is assigned
by the LPAR and z/OS®
currently supports up to
16 TB of flash memory in a
single system image. A
Flash Memory allocation panel
on the SE specifies the
amount of flash memory
initially brought online
to a z/OS partition.
Incremental Flash memory
can be also
subsequently brought
online or offline as needed.
Sizing Flash
Express
Plan to assign the same
amount of memory on
Flash Express as defined
for paging datasets on
disk. Usually one pair of
Flash Express cards
provides enough paging
space for the entire z/OS
partition. There is no
need to perform detailed
capacity sizing to plan
for Flash Express. Adding
Flash Express cards to
your auxiliary storage can
improve paging performance
and availability.
Because Flash Express is
not persistent across
IPLs, it cannot be used
for Virtual I/O or PLPA data
used in warm starts. VIO
and PLPA datasets must
still be defined on disk.
Resiliency
Flash Express cards are
delivered as a RAID 10
mirrored pair for superior
resiliency and reliability.
In the unlikely event of a
problem, Flash Express
cards can also be
concurrently replaced. The
cards are designed for
superior wear leveling and
have a long expected
lifetime.
Security
Your Flash Express data
remains protected. Data
is encrypted on the Flash
Express adapter with
128 bit AES encryption.
Encryption keys are stored
on smart cards that are
plugged into the SE.
Removing the smart cards
renders the data on the
card inaccessible.
Benefits from
Flash Express
IBM Flash Express helps
organizations improve
availability and
performance especially during
periods of paging spikes.
Improving
Availability
Flash Express can improve
availability by reducing
significant paging delays
that might otherwise
affect your system
performance and impact your
mission critical
workloads.
Improving
Diagnostic Time
During diagnostic
collection, as in SVC or standalone
dumps, systems can become
sluggish effectively
rendering key systems
unavailable. When data is
transferred into main
memory as part of a dump, Flash
Express’ fast IO rates and
low latency provide
decreased first failure
data capture time, and faster
page-ins of the critical
pages needed to create the
dump. This allows the
system to return to normal
workload performance
faster, without incurring extra
delays.
Improving
Paging
z/OS uses both Flash
Express and page data sets for
auxiliary storage by
paging data to the preferred
storage medium first,
based on response times, data
set characteristics, and
other parameters. Wherever
possible the system will
page first to Flash Express
resulting in faster
performance. Especially for data
intensive applications the
use of Pageable Large
Pages with Flash Express
enables the transfer of large
amounts of data at faster
speeds, which can result in
improved performance for
DB2 analytic workloads.
Improving
Performance at Transition Times
Banks and financial
institutions need highly
responsive start of day
performance. When the
workload shifts from a
transactional workload, say,
from prime shift to batch
and back to prime shift,
response time delays can
occur. This is due to the
required page-ins of
critical work needed to resume
transactional processing.
These delays can be
dramatically reduced when
data for the next shift is
transferred from flash
into memory. The large number
of page-ins could
otherwise delay performance at
“start of day” or “market
open” activities, vital to
operations like trading
and banking.
Reduce CPU Cycles
Flash Express works to
reduce CPU cycles
associated with page
translations. Typically, page
translations from virtual
to real memory can impact the
performance of workloads
like DB2® or
Java™.
When
using small pages (4K
pages), paging is less efficient
than paging using fewer
larger 1 MB pages
Here
is how it works:
Cache buffers are used by
the operating system to
reduce virtual to real
address translations.
Performance of this
translation can be improved
through the use of having
a greater number of
page entries in cache;
this is made possible
through the use of larger
1MB pages. As a result
of improved cache hits,
exploiters of pageable
large pages and Flash
Express should experience
performance improvements
both in elapsed time
and CPU.
Flash Express
Benefits Many Industries
Flash Express is useful
for any industry needing
improved service levels:
Applications
requiring high availability at the
start of the day like
banks, insurance, trading
applications
Service
providers that compete on outstanding
service levels
Retail
applications with a web presence
Public
sector applications requiring high
availability, like
emergency preparedness
Development
and test teams that collect
diagnostics frequently
Any
organization that needs high SLAs
Bottom line
Flash
Express is designed to improve
availability and can
reduce paging latency at
critical times such as
during morning
transitions or other
periods experiencing
paging spikes.
Flash
Express can improve performance with
pageable large pages,
for instance with DB2
and Java workloads
Flash
Express can also reduce delays from
SVC or standalone dumps
Flash
is automatically secured for security and
compliance needs
Flash
is easily deployed and is easy to
configure
© Copyright IBM Corporation2012
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