P4500 useable storage

[mvoss18]

First time with the P4500s, and just looking for a little guidance on the RAID settings. We have a 3-node cluster setup, each with 12x 600GB SAS drives, so 21.6TB total. We're running SanIQ 9.

The nodes come with hardware RAID 5 by default, and I was looking at the network RAID options and most of them eat up a ton of your usable space when you run those on top of the hardware RAID 5.

I spoke with a rep, and he was suggesting doing Network Raid 5 for our environment, but to not couple that with HW RAID 5. Maybe I'm misunderstanding--so should the HW RAID setting be RAID 0 and the Network RAID set to RAID 5? Or visa versa? We would like to be able to survive with the loss of a single node in our 3-node cluster.

Bottom line, what's the "typical" configuration that balances usable storage with data protection? Doesn't make sense to buy 21TB of RAW storage and only get 8TB usable!

Thanks!

[Sudhakar Subramaniam]

HI,
Yes you are right, the p4000 goes with hardware raid 5 by default..HP recommendation is to have hardware raid 5 and network raid 2, so that they have two non adjacent node level redundancy...they can go for network raid 5 but it is generally not recommended in a performance intensive environment because when we have n/w raid 5 or 6, it takes out some performance in parity writing...but n/w raid 5 gives 1 node failure redundancy and n/w raid 6 gives 2 node failure redundancy. in n/w raid 2,3,4 it doesnt calculate parity and hence a bit faster

[Sudhakar Subramaniam]

in N/w raid 5 you get 60% of storage space utilization and n/w raid 6 gives you 55%

[mvoss18]

I believe the terminology has changed with San/IQ 9. Here are the options we see with a 3 node cluster. I believe NW Raid 6 is available for 4-node clusters.

Network RAID-0 (None)
Network RAID-10 (2â Way Mirror)
Network RAID-10+1 (3â Way Mirror)
Network RAID-10+2 (4â Way Mirror)
Network RAID-5 (Single Parity)

Is Network RAID 2 the same as Network RAID 10 in SAN/IQ 9? With that you would get 8TB usable out of 21.6TB RAW in my environment. Ouch!

I'm under the impression that with San/IQ 9, you can run Network RAID-5 across a 3 node cluster and this will tolerate one of the three nodes going down.

[Mark...]

Hi
Network RAID-0 (None) = N0, same as before
Network RAID-10 = N2
Network RAID-10+1 = N3
Network RAID-10+2 = N4
Network RAID-5 (Single Parity) new with SAN/iQ V8.5
Network RAID-6 (double Parity) new with SAN/iQ V8.5
Mark...