Wednesday, July 23, 2014 2:30 pm
-
2:30 pm
EDT (GMT -04:00)
| Speaker: | Jaemyung Kim |
| Abstract: |
Hot
standby
techniques
are
widely
used
to
implement
highly
available
database
systems.
These
techniques
make
use
of
two
copies
of
the
database,
an
active
copy
and
a
backup
that
is
managed
by
the
standby.
Synchronization
of
these
two
database
copies
is
the
responsibility
of
the
database
systems
than
manage
them.
However,
database
systems
are
often
deployed
in
settings
in
which
a
reliable,
persistent,
network-accessible
storage
service
(such
as
cloud
block
storage
services,
cluster
file
systems,
or
NAS)
is
available.
In
this
paper
we
address
the
following
question:
how
can
we
improve
hot
standby
techniques
in
settings
in
which
the
active
and
standby
database
systems
have
access
to
a
common,
reliable
persistent
storage
service? We present SHADOW systems, a novel approach to hot standby high availability. In a SHADOW system, the active and standby database systems share access to a single logical copy of the database, which resides in the persistent shared storage. SHADOW introduces write offloading, which frees the active system from the need to update the persistent database, placing that responsibilty on the standby system instead. SHADOW systems push the task of managing database replication out of the DBMS and into the underlying storage service. We have implemented SHADOW prototypes using PostgreSQL, and we present the results of a performance evaluation that shows that SHADOW systems outperform traditional synchronous hot standby replication. Because of write offloading, SHADOW systems can potentially outperform even a standalone DBMS, while providing fast failover and durability of committed updates. |