SAN IQ Network RAID 5 = RAID 10+1 and Network RAID 6 = Network RAID 10+2?

[Mi77]

Hi There,

Can I conclude that Network RAID 5 is equal to Network RAID 10+1 (that can withstand one storage node failure), and Network RAID 6 is equivalent to Network RAID 10+2 (that can withstand 2 storage node failure)?

[Bryan McMullan]

Network RAID 5 <> RAID 10+1 and Network RAID 6 <> Network RAID 10+2, they are all mutually exclusive.

Network RAID-5 - Stripe and single parity protection
Network RAID-6 - Stripe and dual parity protection
Network RAID-10 - Stripe and mirrored protection
Network RAID-10+1 - Stripe and triple mirrored protection
Network RAID-10+2 - Stripe and quadruple mirrored protection

[Mi77]

Hi Bryan,

Sir, sorry but I still don't get it. Say I have 6 storage nodes applied with Network RAID 6, does it mean that this 6-node configuration can withstand 2 storage node failure?

If that is the case, then it looks to me like it's almost the same in operation versus a Network RAID 10+2.

Same goes with a 4 storage node configuration implemented with RAID 5 that can withstand 1 storage node failure. Sounds like almost the same when an NRAID 10+1 is applied.

Please help to clear up the confusion Sir.
Thanks.

[Bryan McMullan]

Hopefully this helps -

Network RAID 5 - Stores three data and one parity as a minimum configuration i.e 3+1 , meaning four nodes as a starting point.

Network RAID 6 - Stores four data and two parity as a minimum configuration i.e 4+2 , meaning six nodes are required initially.

Network RAID 10 - Stores two copies of each volumeâ s block, providing continuous data availability across any single node failure.

Network RAID 10+1 - Stores three copies of each block for mission-critical data that needs to be available despite any double node failure.

Network RAID 10+2 - used in situations where a cluster is divided between two locations, and the data must be continuously available in the event of both a site failure and a node failure at the alternate site (Campus SAN).

While the resiliency of the network raid flavors may be similar from one to another. How they are managed, used, and the workloads they are suited to is the real difference. Supposedly Network RAID 5 and 6 provide "space utilization benefits", but the use of snapshots is required to see the benefits (according to the HP/LHN docs). Even HP/LHN suggests RAID5/6 should be used on mostly read, sequential workloads on larger clusters, such as file shares and archiving. Whereas RAID 10+X is more appropriate for highly transactional workloads.

I'm personally sticking with NW RAID-10+x as I've yet to see any real examples of significant storage savings using NW RAID5/6.

Hope that clears things up more.

[Mi77]

Yup got it Sir. Thanks