Thanks MammaGut for replying -appreciated.
As per the first line in the 'Space available in the tiers' section of the 'HPE 3PAR StoreServ Technical White Paper' it states that AO's first job on run is to 'consider available space on tiers'.
Space available in the tiersQuote:
When AO runs, it will first consider available space in the tiers. If a tier has a CPG warning limit or a tier maximum value configured and the tier
space exceeds the lower of these limits, AO will move regions to reduce space consumption below the limit. (Note: If the warning limit for any
CPG is exceeded, the array will generate a warning alert). If space is available in a faster tier, it chooses the busiest regions to move to that tier.
Similarly, if space is available in a slower tier, it chooses the idlest regions to move to that tier. The average tier service times and average tier
access rates are ignored when data is being moved because the size limits of a tier take precedent.
And similar in the '
Adaptive Optimization for HPE 3PAR StorServ Storage' (page 19)
Quote:
StartAO has now been initialized, and the needed data collected or calculated. The next phase will schedule region moves. The first region moves
considered by AO are based on available space. AO will check the CPG’s in the AO configuration for free space. If one or two of the CPGs do not
have sufficient free space, AO will attempt to move regions between tiers to create free space. If sufficient free space is unavailable on all tiers, AO
will stop. This is the phase where AO will consider any tier minimum or maximum values as described earlier in the section titled “Minimum and
Maximum Space within a Tier”. AO will schedule region moves, if necessary, to satisfy any minimum or maximum settings.
As the Best Practice also states that AO Configurations should be run together as they will calculate what needs to be moved at the same time but moves will occur serially - it would kind of sound like a space check would occur before moving each so there would be no simultaneous operation that could fill the tier.
However, all that said, my question was relating to if there are NO Warning limits set will it just go to 100% (or as close to it as it can) usage of the NL Tier until it would essentially resort to swapping around chunks as opposed to move more down?
What I am essentially trying to get to is if I dont add any further NL Disk and it goes to 100% can I just let AO manage this without issue - albeit of course accepting that it wouldnt be entirely balanced and I would have data sat on FC (of which I have a lot free) that probably shouldnt? Like I mentioned before this array has purely AO CPG's and nothing dedicated to the NL tier.
As you mentioned all my User CPG's for the Policies are sat on FC tier, however I noticed 2 rogue VV's that someone has placed on the NL. Is it fine just to tune those 2 on to the FC CPG of that AO policy?
Your advice and time is much appreciated.