topic Re: Usable Storage math question??? in StoreVirtual Storage

Usable Storage math question???

ACK — Thu, 07 Apr 2016 19:47:17 GMT

One quick question on storage.

If I have 4-4TB VSA’s and I add a 1-8TB VSA and I use all Netowrk Raid10 Vols, how much usable storage will I have?

4tb

8tb

Next if I have 5-4TB VSA’s and use all Network Raid10 Vols, how much usable storage will I have?

4tb

Thanks

Re: Usable Storage math question???

oikjn — Thu, 07 Apr 2016 20:19:52 GMT

the same amount. the 8tb one will only contribute 4tb to the cluster.

think of the nodes like HDDs in a traditional raid. the usable space from any HDD (or node) is only equal to the size of the smallest HDD (or node in this case).

just like HDDs, don't mix sizes and don't mix performance. The system will only be as large as the smallest node and only as fast as the slowest one.

Re: Usable Storage math question???

oikjn — Thu, 07 Apr 2016 20:24:03 GMT

side note.. don't get destracted by NR5 or NR0. NR10 is the ONLY real option for live data. NR5 is ok for static archive date and NR0 is good for pretty much nothing as it will go offline at least every time you do a maintenance update.

Given that and assuming you add nodes which are all matching sizes, then each VSA node you add will effectively increase your usable LUN size capacity by 1/2 its actual size.

Re: Usable Storage math question???

Torsten. — Thu, 07 Apr 2016 21:05:01 GMT

raid10 - think about a mirror, a big and a small capacity - the smallest and the slowest is setting the limit, as always for a raid.

Re: Usable Storage math question???

ACK — Thu, 07 Apr 2016 21:08:38 GMT

That was my suspicion. Thanks for the clarification.