Tiered Storage and Caching

Courtesy:  ServeTheHome.com

Answering the concern of adding power consumption (including heat), additional rack space and etc. for additional enclosures, as well as performance concerns is the larger enterprise storage chain. 3.5″ SATA or SAS drives are used for mass storage (including potentially disk based backup instead of tape), 2.5″ and/or 3.5″ SAS or SSDs are used as the next tier of storage. With these large systems, disks are often contained in multiple shelves requiring a Fibre Channel, SAS, or Fibre Channel over IP connection between the dedicated controller (or controllers) and the disks.

To answer the need for more performance, many vendors such as HP, NetApp (PAM II module pictured above), EMC, and etc are using local NAND cache, often using a PCIe add-in card. This gives the system very high performance solid state caching inside the controller enclosure instead of through external cabling.  Things like having 4TB of NetApp’s PAM II PCIe modules are probably out of reach for most small businesses and home server aficionados, however they do serve a great value in enterprise applications. As an aside, this is similar to what happens when one uses a RAID controller that can incorporate SSD caching on the hardware RAID card.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s