will there be any performance hit when i use Flash and SSD's in a single pool.
It's certainly possible, and others have done exactly that. As long as the performance of the Virtualized SSD array is very good, and the HUSVM doesn’t over run it this works. You may find that the HUSVM internal SAS tier outperforms the external SSD array for some types of workload (sequential read, sustained write). So depending on the predominant workload in the pool, you may need to adjust tiering policies.
It's not what you’d chose to do if you were starting with a blank slate and $$$, but if you already have the arrays, it's a valid combination.
I assume you mean FMD and SSD? I'd question on why you would want to do it......
FMD have better performance than SSD, so in theory you could end up with some performance difference.
keeping in mind that i will be doing HDT.
how about having Flash and SAS in one pool vs externalized SSD's and SAS in one pool.
i know there will be some perf hit...
will that be negligible or noticeable.
External storage will be slower. You would ideally have the flash media (FMD and SSD) in the VSP, and use the external storage for cold data and low performance data.
It will be noticeable. There will be performance impact when you compare your virtualized pool with that of internal pool.
And moreover there should not be any disturbance in the connectivity. If you are really concerned about the performance bottleneck keep it internal to the storage.
yes i understand that..
we have a storage array ( only SSD's in it), but doesn't have replication on that array.
so planing to virtualize that array and replicate through HUSMV's..
in that case can i say that :
HUSVM's Flash as Tier 0
Virtualized Storage Array with SSD's as Tier 1
HUSVM's SAS as Tier 2.
if i keep all these 3 Tiers in single pool.
will my external SSDs perform almost equal to internal SAS drives, will there be any benefit or not ?
or external SSD's and internal SAS give me same/almost equal perf ?
I don't think there will be much benefit. When the data gets migrated from one Tier to another there will be heavy load applied based on the amount of data that gets migrated between the upper and lower tiers.
And moreover the internal architecture of HUSVM works in a different fashion and your virtualized storage will work different.
From my experience I can say there are a lot of facts you need to consider before going for such implementation.
Get in touch with your local account manager, so that you requirements will be well understood and they will work towards your requirements.
Agreed, but I'm wondering what a valid use case will be in having them both in an internal pool. I'm thinking about it in the context of addressing a random read workload and I'm not sure mixing these two storage classes will yield tangible benefits. In theory both should provide sub-ms response time, add cache and I can't think of many workload that would get any real benefit.
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