What is meta volume creation logic in ViPR?

Hi Tim,

ViPR supports below types of Meta:

1. VMAX Striped Thin
2. VMAX Striped Thick
3. VMAX Concatenated Thin
4. VMAX Concatenated Thick

VMAX Striped Thin

By design VMAX Striped Meta devices offer best read and write performance under different workloads. Based on the engineering best practice, ViPR always creates Striped meta volumes as multiplication factor of 8 (8-way, 16-way, 32-way, etc) with the total capacity being shared equally between all the meta members. Once the meta members size as reached 32 then the next set of members will always be an incremental fashion.

For instance, if an auto meta size is configured as 16GB then creating a 500GB volume would create a total of 32 devices. Meta member calculation is done as (total requested capacity)/(Configured auto meta size) which is 500GB/16GB = ~31.25 rounding it to 32 devices. Once we calculate total members we will then calculate the capacity for each member and it is calculated as (total requested capacity)/(total members) which is 500GB/32 members = ~15.6 GB rounding it to 16GB each. By this calculation, for a 500GB volume where auto meta was configured with 16GB then user will end up with 32 members each of 16GB.

Things to Remember:

1. Vmax Striped Thin Meta’s will always be multiple of 8 until 32 and then an incremental fashion
2. Total requested capacity will always be equally distributed within all members
3. As a process of above, step #1 will be calculating total members which is based on (total requested capacity)/(Configured auto meta size)
4. Once members are calculated then step #2 which calculating capacity for each member. This can be achieved as (total requested capacity)/(total members)

VMAX Striped Thick

VMAX Striped Thick will always be multiple of 4 (4, 8, 16, 32) Beyond 32 will be an incremental fashion. ViPR also has a pre-defined range until certain capacity, we either create meta based on the below range or Configured auto meta limit (whichever is less).

VMAX Concatenated Thin/Thick

ViPR always uses multiples of auto meta size for Vmax Concatenated Thin / Thick volumes.  For instance, if an auto meta size is configured to 16GB then creating a

1. Volume less than the configured auto meta will create a single volume
2. Volume of 100 GB then ViPR would calculate meta members as (Total capacity ) / (Configured Auto Meta size) which is 100GB / 16GB = ~ 7
   1. Once the members are calculated then capacity for each member would be calculated as (Total capacity) / ( (Number of Memebrs) which is 100GB / 7GB = ~15

Thanks,

Dee