Problems solved, introduced and left unsolved by cloud storage

Cloud whisps (sic) by turtlemom4bacon (cc) (from flickr)
Cloud whisps (sic) by turtlemom4bacon (cc) (from flickr)

When I first heard about cloud storage I wondered just what exactly it was trying to solve. There are many storage problems within the IT shop nowadays days, cloud storage can solve a few of them but introduces more and leaves a few unsolved.

Storage problems solved by cloud storage

  • Dynamic capacity – storage capacity is fixed once purchased/leased. Cloud storage provides an almost infinite amount of storage for your data. One pays for this storage, in GB or TB per month increments, with added storage services (multi-site replication, high availability, etc.) at extra charge. Such capacity can be reduced or expanded at a moments notice.
  • Offsite DR – disaster recovery for many small shops is often non-existent or rudimentary at best. Using cloud storage, data can be copied to the cloud and accessed anywhere via the internet. Such data copies can easily support rudimentary DR for a primary data center outage.
  • Access anywhere – storage is typically local to the IT shop and can normally only be accessed at that location. Cloud storage can be accessed from any internet access point. Applications that are designed to operate all over the world can easily take advantage of such storage.
  • Data replication – data should be replicated for high availability. Cloud storage providers can replicate your data to multiple sites so that if one site goes down other sites can still provide service.

Storage problems introduced by the cloud

  • Variable access times – local storage access times vary from 1 and 100 milleseconds. However, accessing cloud storage can take from 100’s of milleseconds to minutes depending on network connectivity. Many applications cannot endure such variable access times.
  • Different access protocols – local storage support fairly standard access protocols like FC, iSCSI, NFS, and/or CIFS/SMB. Barring the few (but lately increasing) cloud providers that provide NFS access protocol, most cloud storage requires rewriting applications to use new protocols such as REST to store and access cloud file data.
  • Governance over data – local storage is by definition all located inside one data center. Many countries do not allow personal and/or financial data to be stored outside the country of origin. Some cloud storage providers will not guarantee that data stored in the cloud couldn’t be stored outside the country and jurisdiction of a single country.

Storage problems not solved by the cloud:

  • Data backups – data protection via some form of backup is essential. Nothing says that cloud storage providers cannot provide backup of data in the cloud but few if any provide such service. See my Are backups needed in the cloud post.
  • Data security – data security remains an ongoing problem for the local data center moving the data to the cloud just makes security more difficult. Many cloud storage providers provide rudimentary security for data stored but none seem to have integrated strong authentication and encryption services that might provide true data security.
  • Energy consumption – today’s storage consumes power and cooling. Although, cloud storage can be more efficient than onsite storage, this does not eliminate the environmental cost of storage.
  • Data longevity – data stored in the cloud can just as easily go obsolete as data stored locally.

Probably some I have missed here but these are a good start.