Module 10: Data Protection (Data Replication) Flashcards
What is data replication?
process of creating an exact copy of data to ensure business continuity
What is a source/production LUN?
LUNs that compute system access on production storage system
What is a target LUN?
LUN on which the production data is replicated
What is the reason to do replication instead of a normal backup?
normal backup places additional burden on prod infrastructure since LUNs are involved in prod/backup operations
What is local replication?
replicating data within the same location
What is remote replication?
replicating data to remote locations
What are snapshots?
virtual copy of a set of files, VMs or LUNs as they appeared at a specific point in time (PIT)
What is the benefit of snapshots?
can establish recovery points in a small fraction of time and reduce RPO
What is a VM Snapshot?
preserves the state and data of a VM at a specific PIT
includes power state of a VM and includes all files
What are storage system based snapshots?
provide space optimal pointer based virtual replication
How does a storage based snapshot work?
at time of replication session the snapshot contains pointers to the location of the data on the source
snapshot doesn’t contain any data - known as virtual replica
What is cloning?
provides the ability to create fully populated PIT copies of LUNs within a storage system or create a copy of an existing VM
How does cloning of a storage volume work?
initial synchronization is performed between the source LUN and clone - during synchronization clone is not available to servers
What is the existing VM called in a VM clone?
Parent VM
What is a full clone in VM cloning?
an independent copy of a VM that shares nothing with the parent VM
What is a linked clone in VM cloning?
created from a snapshot of the parent VM
What is synchronous replication?
write is committed to both the source and remote replica before it is acknowledged to the compute system - zero RPO
How does synchronous replication work?
write IO received from compute into cache of source
write IO transmitted to the cache of target storage
receipt acknowledgement provided by target back to source
source sends acknowledgement back to compute
What is asynchronous replication?
write is committed to the source and immediately acknowledged by compute system
How does asynchronous replication work?
write IO received from compute system into cache of source
receipt acknowledgement by source to compute
write IO transmitted to target cache
target sends acknowledgement back to host
What is continuous data protection (CDP)?
provides the capability to restore data and VMs to any previous PIT
What are the key components of CDP?
Journal Volume
CDP Appliance
Write Splitter
How does CDP work?
data changes are continuously captured and stored at a separate location from the prod volume
What is a journal volume?
contains all data that has changed from the time the replication session has started
amount of space that is configured for the journal determines how far back recovery points can go
What is a CDP appliance?
intelligent hardware platform that runs the CDP software - manages both the local/remote replication
can also be a virtual appliance
What is a write splitter?
intercepts writes to the production volume and splits each writes into two copies
What is a replica?
an exact copy/image of your data within your storage environment
What is a backup?
exact copy but off the storage array environment entirely
What is local replication?
where we take a copy and put it in the same array as the source LUN
How does local replication work?
going to create another LUN as same size as source in the same array
going to take full copy and mirror - will create PIT
can now allocate second LUN to separate server for read/writes
What is virtual pointer based replication also called?
snapshots
What is a pool of thick devices called to create snapshots from?
Save Pool
What is the purpose of a save pool?
source of storage for pointer devices
