Discover Technology: EMC VNX2

1. Useful Link

2. Background

Fully Automated Storage Tiering for Virtual Provisioning (FAST VP). FAST VP can both lower Total Cost of Ownership and simultaneously increase performance by intelligently managing data placement at a sub-LUN level. When FAST VP is implemented, the storage system measures, analyzes, and implements a dynamic storage tiering policy much faster and more efficiently than a human analyst could ever achieve.

VNX FAST VP, or Fully Automated Storage Tiering for Virtual Pools tracks data in a Pool at a granularity of 256 MB – a slice – and ranks slices according to their level of activity and how recently that activity took place. Slices that are heavily and frequently accessed will be moved to the highest tier of storage, typically Flash drives, while the data that is accessed least will be moved to lower performing, but higher capacity storage – typically NL-SAS drives. This sub-LUN granularity makes the process more efficient, and enhances the benefit achieved from the addition of Flash drives.
The ranking process is automatic, and requires no user intervention. When FAST VP is implemented, the storage system measures, analyzes, and implements a dynamic storage-tiering policy in a faster and more efficient way than a human analyst. Relocation of slices occurs according to a schedule which is user-configurable, but which defaults to a daily relocation. Users can also start a manual relocation if desired. FAST VP depends for its operation on tiers of disks – up to 3 are allowed, and a minimum of 2 are needed for meaningful FAST VP operation. The tiers relate to the disk type in use. Note that no distinction is made between 10k rpm and 15k rpm SAS disks, and it is therefore recommended that disk speeds not be mixed in a tier.
NOTE: VNX systems running MCx code use 256 MB slices. Other VNX models, such as the VNX5700 and VNX7500, use 1 GB slices.

FAST VP enables the user to create storage pools with heterogeneous device classes and place the data on the class of devices or tier that is most appropriate for the block of data. Pools allocate and store data in 256 MB slices (earlier versions used 1 GB slices) which can be migrated or relocated, allowing FAST VP to reorganize LUNs onto different tiers of the Pool. This relocation is transparent to the hosts accessing the LUNs.
For example, when a LUN is first created it may have a very high read/write workload with I/Os queued to it continuously. The user wants that LUN to have the best response time possible in order to maximize productivity of the process that relies on this storage. Over time, that LUN may become less active or stop being used and another LUN may become the focus of the operation. VNX systems configured with EMC’s FAST VP software would automatically relocate inactive slices to a lower storage tier, freeing up the more expensive storage devices for the newly created and more active slices.
The administrator can use FAST VP with LUNs regardless of whether those LUNs are also in use by other VNX software features, such as Data Compression, SnapView, MirrorView, RecoverPoint, and so on.
The tiers from highest to lowest are Flash, SAS, and NL-SAS, described in FAST VP as Extreme Performance, Performance, and Capacity respectively. FAST VP differentiates each of the tiers by drives type, but it does not take rotational speed into consideration. EMC strongly encourages to avoid mixing rotational speeds per drive type in a given pool. FAST VP is not supported for RAID groups because all the disks in a RAID group, unlike those in a Pool, must be of the same type (all Flash, all SAS, or all NL-SAS). The lowest performing disks in a RAID group determine a RAID group’s overall performance.

FAST VP policies are available for storage systems with the FAST VP enabler installed. The FAST VP feature automatically migrates the data between storage tiers, and within storage tiers, to provide the lowest total cost of ownership. FAST VP Pools are configured with different types of disks (Flash, SAS, and NL-SAS) and the storage system software continually tracks the usage of the data stored on LUNs in the Pools. Using these LUN statistics, the FAST VP feature relocates data (At a granularity of 256 MB) to the storage tier that is best suited for the data, based on the policy. Relocation within a tier ensures that hot spots are reduced or eliminated.

Use the “Highest Available Tier” policy when quick response times are a priority.

A small portion of a large set of data may be responsible for most of the I/O activity in a system. FAST VP allows for moving a small percentage of the “hot” data to higher tiers while maintaining the rest of the data in the lower ties. The “Auto Tier” policy automatically relocates data to the most appropriate tier based on the activity level of each data slice.

The “Start High, then Auto Tier” is the recommended policy for each newly created pool, because it takes advantage of the “Highest Available Tier” and “Auto-Tier” policies.

Use the “Lowest Available Tier” policy when cost effectiveness is the highest priority. With this policy, data is initially placed on the lowest available tier with capacity.

User can set all LUN level policies except the “No Data Movement” policy both during and after LUN creation. The “No Data Movement” policy is only available after LUN creation. If a LUN is configured with this policy, no slices provisioned to the lUN are relocated across tiers.

Provided the FAST enabler is present, select the Tiering tab from the Storage Pool Properties window to display the status and configuration options.
Scheduled means FAST VP relocation is scheduled for the Pool. Data relocation for the pool will be performed based on the FAST schedule in the Manage Auto-Tiering dialog. If a tier fills to 90% capacity, data will be moved to another tier.
The Relocation Schedule button launches the Manage Auto-Tiering dialog when pressed.
Data Relocation Status has several states. Ready means no relocations in progress for this pool, Relocating means relocations are in progress for this pool and Paused means relocations are paused for this pool.
Data to Move Down is the total amount of data (in GB) to move down from one tier to another; Data to Move Up is the total amount of data (in GB) to move up from one tier to another; Data to Move Within is the amount of data (in GB) that will be relocated inside the tier based on I/O access.
Estimated time for data relocation is the estimated time (in hours) required to complete data relocation
Note: If the FAST enabler is not installed, certain information will not be displayed.
Tier Details shows information for each tier in the Pool. The example Pool has 2 tiers, SAS (Performance) and NL-SAS (Capacity).
Tier Name is the Name of the tier assigned by provider or lower level software.

3. Hand-on Lab

From the top menu:
1. Hover over Storage
2. Select Storage Pools

In the Pools section:

1. Locate and select the Marketing - Social Media pool
2. Click the Properties button in the bottom menu

In the Properties window:
1. Navigate to the Tiering tab. Notice that we have the ability to use three different tiers in a single pool (Extreme Performance, Performance, and Capacity). You can also see that each tier has its own RAID Configuration.
2. Click OK to exit the properties window

Create LUN
1. Right-click the Marketing - Social Media pool
2. Select Create LUN

In the Create LUN window:
1. Select the size of the LUN to be 10GB
2. Name the LUN Marketing - Social Media Pictures and Videos

Lowest Available Tier

1. Once the LUN has been named, select the Advanced tab at the top of the window
2. In the FAST Settings section, change the Tiering Policy to Lowest Available Tier
3. Click Apply