emcmagic
2 Iron

What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

both are based RVA technology, and can dynamically move data between protected array's. FAST is automatic process based on defined policy, is Virtual lun a manual process?

I could not straight these out...

Thanks!

Labels (1)
1 Solution

Accepted Solutions

Re: What are differences btw Virtual LUN and FAST?

Jump to solution

Yes,

Virtual LUN is a manual migration process intended for moving a LUN within a single array.

FAST is an automated process for moving an entire LUN between multiple tiers of storage (SSD, FC, SATA) based on actual workload characteristics, and in comparison to other LUNs on the system.

FASTVP is a more advanced automated process that moves portions of a LUN (as small as 768KB) between multiple tiers of storage (SSD, FC, SATA) based on the workload. This requires pools, but is far more efficient and effective when compared to FAST(nonVP).

0 Kudos
21 Replies

Re: What are differences btw Virtual LUN and FAST?

Jump to solution

Yes,

Virtual LUN is a manual migration process intended for moving a LUN within a single array.

FAST is an automated process for moving an entire LUN between multiple tiers of storage (SSD, FC, SATA) based on actual workload characteristics, and in comparison to other LUNs on the system.

FASTVP is a more advanced automated process that moves portions of a LUN (as small as 768KB) between multiple tiers of storage (SSD, FC, SATA) based on the workload. This requires pools, but is far more efficient and effective when compared to FAST(nonVP).

0 Kudos
emcmagic
2 Iron

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

Then why or in what situations do I need to use Virtual LUN?

0 Kudos
dynamox
6 Thallium

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

if you want to manually move device between different pools or tiers

0 Kudos
Shanmugas
1 Nickel

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

Virtual LUN is Thin LUN created on Thin Pool. The pool can have SSD/FC/SATA tiers with varying RAID Groups. FAST VP Moves hot bits of LUN to various drive types. You cant compare these technologies, they work together.

0 Kudos
Highlighted

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

Shanmugas,

Technically this is true.. a TDEV is basically a Virtual LUN on top of a pool.  FASTVP can manage the tiering of a Virtual LUN (aka TDEV).

Most of the time however, when someone refers to VirtualLUN on VMAX, they are actually referring to VLUN Migration and it's just being shortened.  When referring to the LUN itself, most people say Host LUN, LUN, TDEV or Thin Device.  So the earlier replies on this original question assumed that emcmagic was referring to VLUN migration rather than just the VLUN.  This may have been an error on our part.

For Clarification..

STD or Device is a host LUN created from DATA devices (or hypers) of specific disks, not associated with a thin pool.  This is as close to a traditional LUN on RAID Group as you can get on Symmetrix.

TDAT or Thin Data devices are essentially hypers of specific disks that are aggregated to create a Thin Pool

VLUN and TDEV are synonymous, essentially a host LUN created from a Thin Pool

VLUN Migration is a manual operation used to move a Host LUN between pools or tiers

FAST is an automated service that tiers entire host LUNs between tiers based on workload

FASTVP is an automated service that tiers sub-LUN segments between tiers based on workload.


emcmagic
2 Iron

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

Hi Rich,

You understood my question correctly. Thanks for all your clarifications.

Now since you brought up, are there STD devices  in VMAX world as well? As far as I know, the closest one in VMAX is TDAT device, and we use it only for Thin pool, not to create LUN on it. We only use Thin device to bound thin pool, and then provision it to hosts. Am I correct here?

0 Kudos
Shanmugas
1 Nickel

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

"someone refers to VirtualLUN on VMAX, they are actually referring to VLUN Migration and it's just being shortened." - I think that is pretty weird to call VirtualLUN for LUN migration. If someone refers like that in my company, I am going smack them. j/k


STD refers to standard device, created using hyper(s), basically a thick device. It is going to be one of the rare species in the future.

0 Kudos

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

Yes, STD devices are supported on VMAX, but you'd essentially be doing that outside of, or instead of pools and TDAT/TDEVs.  You can have some disks configured outside a pool and create STD devices on them, and other disks in a pool.

VMAX10K systems support pools only, but 20K and 40K can support pools and STD devices.

emcmagic
2 Iron

Re: What are differences btw Virtual LUN, FAST and FAST VP?

Jump to solution

I did not know we could use STD, in addition to use POOL, although I don't know if there are any reasons to do so.

What commands to determine if we are using STD device on 20K?

0 Kudos