Question about data resiliency inside one host

[vincenjw]

Hello,

I'm building a streched cluster with 2 hosts and i have a question about the resiliency.

With two hosts (with 3 DG in each of them) I would like to configure a FTT=1 betweend both site but can i use also the local resiliency inside one site with FTT=1 ?

In other word, Does vSAN will replicate my data locally between my 3 disks groups or not ? I would like to protect my streched cluster againt one host failure + one disk failure on the remaining host.

Thanks for your help !

Vincent

[parmarr]

Yes, this is possible. vSAN 6.5 and previous versions mirror data across sites for redundancy. If a disk, host, or an entire site

goes offline, the data is still available at the other site. When the offline disk, host, or site comes back

online, data is resynchronized to restore redundancy but

vSAN 6.6 includes local failure protection. RAID-1 mirroring or RAID-5/6 erasure coding can be

implmented within each strecthed cluster site to provide local resiliency to disk and host failures. In

addition to providing higher levels of redundancy, this minimizes production and resynchronization

traffic across the inter-site link.

[TheBobkin · Accepted solution]

Hello Vincent,

No, unfortunately this is not currently possible with a 1+1+1 cluster,  parmarr appears to have misunderstood your question.

The nearest available feature to what you are describing is Local Protection via PFTT/SFTT (in vsan 6.6 and higher) and this requires as many nodes per site as the Fault Tolerance Method of the Storage Policy requires e.g. 3 data-nodes per site to use FTT=1(RAID1) (3+3+1 stretched-cluster).

More info:

yellow-bricks.com/2017/05/30/sizing-vsan-stretched-cluster/

Bob

[vincenjw]

Hello Bob,

Thanks for your answer. It's what i thought... in the meantime I tested it with a single vSAN host.

Maybe later...