Starwind VSAN & Storage Spaces 2016

[Sergey Pugachov]

Hi.

I read through your guides implementing 2 node cluster on top of Storage Spaces instead of hardware raid. Obviosly, most exciting feature in such design is tiering. I will try to validate such design in lab, but i need to ask a few questions first (before i start purchasing hardware).

By now, it's seems that 4 TB total storage capacity will be sufficient for our needs. I guess that there are much less than 1TB of hot data. So:

1TB SSD tier - 1 column, mirror resiliency - 2 x 1 TB SSD
6 TB HDD tier - 2 column, mirror resiliency - 4 x 3 TB HDD (i already have this disks)
2 port 10G Ethernet adapters on nodes (1 port Starwind sync, 1 port iSCSI)

First question! Hot/cold tier capacity ratio is significant less than reccomended by MS (30%). But if hot data less than 1TB, i think it is not real problem.

I plan to place two ha-device on single storage space disk.

Second question! 10G Ethernet for sync traffic between nodes will be enough in such desing? 1 SSD = ~500 MB/s read/write, 4xSSD = 2GB/s, and this is greater than 10G Ethernet throughput. I believe, such calculations are slightly naive. Will be a 10G network become a bottleneck?

Third and last question. What about flash memory wearing? Is there some addition load by starwind sync or Storage Spaces tiering? Can i just assume, that 1GB of data written to endpoint vhdx will be written on each 4 SSDs?

[Oleg(staff)]

Hi Sergey,

First question! Hot/cold tier capacity ratio is significant less than reccomended by MS (30%). But if hot data less than 1TB, i think it is not real problem.

Yes, you are right, that is not a problem.

Second question! 10G Ethernet for sync traffic between nodes will be enough in such desing? 1 SSD = ~500 MB/s read/write, 4xSSD = 2GB/s, and this is greater than 10G Ethernet throughput. I believe, such calculations are slightly naive. Will be a 10G network become a bottleneck?

Actually, you are right again. 10G Ethernet can be the bottleneck or read operations, but this bottleneck is not so critical in your case.

Third and last question. What about flash memory wearing? Is there some addition load by starwind sync or Storage Spaces tiering? Can i just assume, that 1GB of data written to endpoint vhdx will be written on each 4 SSDs?

In case of Mirror yes, StarWind HA replica on each server and mirrored on Storage Space level.

[Sergey Pugachov]

If i use storage spaces as data storage, should I disable all types of caching in starwind vsan?

[Oleg(staff)]

Yes, you will have SSD cache already configured on the level of underlying storage for StarWind.