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vSphere 6.5 1 host local storage What do you think?

Hey all

Small environment, two hosts, replicating using Veeam from hosta to hostb.  Target was about 8TB usable with 900GB 15k drives.
I can do 11 spindles with a hotspare at 900GB  raid 6 which would bring us to 8.1 TB.

OR, I kind of like the idea even though RAID 6 of two volumes for the VMs
Two volumes with 7 900s RAID 6 with RAW storage of 4.5 TB per volume.  Does everyone feel that much safer with the two volumes, rather than the one 11 spindle volume?  Or is it a waste of $$$$$

There will be a second physical server we will be replicating too, but no shared storage

Thoughts?
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kevinhsieh
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I hope you already have the drives, because 15K drives are a waste of money these days. SSD is cheaper and faster.
Two RAID 6 volumes is probably a little safer than one large RAID 6 because rebuilds should be a little quicker, but your performance will be significantly reduced. The safest configuration is actually to put all drives into RAID 10. That yields almost the same useable capacity as the two RAID 6, but is safer and much much faster. RAID 6 with 15K drives is like buying a Mustang to tow a boat.
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LICOMPGUY

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Hey Kevin

Where are you seeing SSDs matching the capacity for less of a price than 15k drives?  Ok, I double-checked it appears they are about 200-250.00 more per SSD.  I do wonder about the MTBF on SSDs though.  I really wonder if they will last as long as a standard spindle drive. I can see the client attempting to keep the server in prod for as long as 7 years. (Based on history).

I would have to agree with splitting into two volumes so each vol comes off of a different channel of the RAID controller, that could yield better performance.
Why would you think performance would be SIGNIFICANTLY reduced, I would think it would be practically unnoticeable - no?
Are you suggesting that the bottleneck would be the controller and the writing of the parity info to 11 spindles?  If the 15ks are able to write faster and they are, (than 10k drives),  I wouldn't think it would be like towing a boat with a mustang.  Excellent analogy btw. ;-)

Thank you again so much I value your input!
Just go to Dell.com and price out a new server. Compare cost of storage per usable GB when using 15K drives in RAID 10 vs read intensive SSD in RAID 5. Last I checked, SSD wins. SSD even beat 10K SAS on usable per GB metric.

Perhaps a better analogy for 15K drives in RAID 6 is buying a dragster, and trying to do a 1/4 mile with the drag chute deployed. The performance penalty for RAID 6 is significant. Why pay such a price premium for 15K drives if you're going to cripple their performance by putting them into RAID 6?
Hey Kevin

I have been going with RAID 5 with a hotspare for the longest of times, only had two issues where once I lost two drives in one RAID volume in about 20 years, but someone who was kind enough to field my questions here, opened my eyes to some of the issues he has seen with RAID 5 and he encountered a bit of dataloss. So I was thinking RAID 6 with a hotspare would be a good place to be. RAID 10 essentially doubles our cost of storage, so I don't want to really go there.  Although the client doesn't have shared storage we were going to have two hosts and replicate the VMs for Bus Continuity to the second host, in the event of catastrophic failure on host a.  I will take a look again over the weekend on SSDs and RAID 10, but I do think the price goes up substantially and it always or at least to a degree comes down to $$$$$

How often do you actually implement RAID 10? I only had one site that was willing to spring for that for a mission critical database on an IBM box.
Thanks!!!
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kevinhsieh
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Kev/all

Thanks so much for bringing these issues to light. We are going with RAID 10, 10k drives for this solution, I get it now.
Thanks again!