Pool Rebalacing and new luns

Thanks! So the right way is to wait for et rebalancing to finish, before provisioned new luns so i don't get non-optimally lun layout ?

Any one else have a comment on this ?

honestly i don't know how it's going to layout your 1g/256mb slices if rebalancing is in progress. I sure hope it would not put new slices just on the new drives (like it did in block oe 31).

In Flare 32, when you create a new LUN it will spread the data over all the disks in the Pool (depending on the size of the new LUN - a very small LUN would probably use only one internal raid group initially) - that includes the new disks if you just added them. Part of Auto-tiering in R32 is the re-balancing within a tier. And the default is HIGH : Auto - which means all new data will first go to highest tier, then re-balance down overtime.

If the initial re-balancing is running after you expanded the Pool, the new LUNs should still use all the disks present in the Pool.

I'd recommend letting the initial re-balancing finish - it takes time and why add more overhead if you don't need to.

glen

There is a lot of things that will impact this...

First thing is which tiers did you expand, all tiers or just some of them ?

Second is how you create the new luns, and the amount of free space you have in each tier..

If you choose the default start high then auto tier, the new luns will end up on the fastest possible disks starting from SSD to SAS and down to NL-SAS..and then autotier from there

But if you choose the old standard your data will be placed according to free space in the diffetent tiers, and that will probably mean most of the data goes to Nl-SAS, and then auto tier from here on..

One thing that is important here is if the array has FAST VP Enabled or not...

If FAST VP is enabled the newly created luns will be distributed over all the spindels at the next run of the autotiering schedule...In that case I cannot see the big difference...

If you dont have the FAST VP enabled the array will just do a rebalance once, and in that case I'd reccommend getting the luns in place before expanding the pool if at all possible...and if that is not possible let the array finish rebalancing before adding more luns and Data...

Great thanks you all for you comments

/Kenneth

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glen