VSAN

[ChevUribe]

I would like to ask a few questions regarding VSAN:

1. If a VM is subjected to VSAN storage policy for example FTT=1, what is the secondary copy VM? Is it thick or thin provisioned?

2. Lets say I have 3 SSD and 6 SAS disk per host?

- Can I configure it as 3 SSD as 1 RAID 0 group and 5 SAS as 1 RAID 0 group?

- Configure this with each SSD and each SAS with RAID 0 separately?

[elerium]

1. The policy you specify would also specify thick or thin (default is thin). The secondary copy will use the same thick/thin as the 1st copy.

2. You can't specify SSD or magnetic storage for VMDKs, capacity layer will always be magnetic. The SSDs in VSAN hybrid model are used as a cache, you can specify how much cache to allocate but this is recommended to be left at 0 (automatic cache level for VSAN).

[ChevUribe]

2. You can't specify SSD or magnetic storage for VMDKs, capacity layer will always be magnetic. The SSDs in VSAN hybrid model are used as a cache, you can specify how much cache to allocate but this is recommended to be left at 0 (automatic cache level for VSAN).

- I mean before the disks per host will be presented for VSAN configuration, do I have to configure each disk as RAID0 or I can pool the SSDs as 1 RAID0 group and the magnetic disks in 1 RAID0 group?

[elerium]

I would try to avoid controllers that are only supported in RAID0 in VSAN and use a raid controller that can support passthrough. But if you must use them, each disk should be configured as an individual RAID0. Do not pool multiple disks into a RAID0 group since a single failure in this scenario will down all the data in the raid group.

This KB may also be helpful with specific raid0 settings https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=21112...