As a consultant I
receives many queries regarding the data security on cloud and also the
durability of data on cloud. So I am writing this post assuming your basic knowledge
of cloud demon.
Everyone knows that cloud object storage is highly durable
99.99999999%,But what about the block
storage (AWS EBS, Softlayer virtualDrive, etc.)?
The failure
rate of block storage on cloud is 0.1% to 0.4% every year. It is very important
to have a backup of cloud block storage or entire cloud instance (VM) to either on cloud
storage or on-premise.
There are many
ways we can take backup of cloud instance, and each type of cloud backup
has its own pros and cons.
1)
Application Level Backup
2) VM
level backup of cloud instance
3) OS
Level Backup of cloud instance
3) File
level backup of cloud instance
The backup
solution type selection depends on the application, data and user requirement
in terms of RTO(Recovery time objective).
Lets
discuss each in detail,
1) Application Level Backup
Application level backup is always seems to be as Da Vinci's
demon. Each type of application backup are different. Let's consider AWS as
common cloud terminology for simplicity
If we consider Database as Application then we can use
native tools for backup and we can store it to S3 object storage. 3rd party tools (eg. Cloudberry) also can be very helpful for database backup to cloud storage.
There are also tools available to take backup of database
to on-premise local storage but as i mentioned these demons will not allow you
to achieve low RTO of database or application.
2) Cloud Instance backup (VM Level):
These kind of backup can provide acceptable RTO for
production environment. every cloud service provider provides snapshot level
backup. these snapshot will be stored in cloud object storage (Extra cost per
GB per month). In order to take the backup of cloud instance as FULL backup
optionally you can use Import/Export feature of cloud service provider.
3)OS Level Backup of cloud instance:
OS level backup requires 3rd party agent to be installed
in cloud instance (eg. Cloudberry). you can redirect cloud instance data to you
local storage or cloud storage using these tools. The RTO of this kind of
backup's restore will be higher than VM level backup type.
4) File Level Backup of Cloud instance:
File level backup always requires require 3rd party
backup software to automate backup task as well as perform encryption and
compression to files. The RTO of file level backup depends on types of file.
(eg. if you are restoring only document files then RTO will be very less but if
you are restoring Database files then RTO will increase because these database
files later need to be restored to database engine also)
After considering the
type of backup next step is to decide weather to take backup in same cloud
storage or other cloud storage or take backup locally
The
quest of backup storage options depends on where do you want to restore your
production machine in case of failure.
->
If you want to restore the data to same cloud instance i would prefer to
select same cloud backup storage.
-> If
you want to restore the data to other cloud service provider infrastructure
then select specific cloud service provider object storage(It can also work as
cloud migration strategy)
-> If
you want to restore entire server to on premise as virtual machine or physical
host then select on-premise storage.
Above discussion was more generic without any specific tools and
solution. after selecting the proper type of backup solution we can select
available tools for the same.