Multiples backing disks with one big caching ssd

[tdsn0007]

I have one system with 18 HDD disks of 18TB. I need to caching for write this system. First I think about dm-writeboost. I ready doc and quick start and have few questions:

1- Is possible to use one large NVME SSD (7TB disk) to cache many backing disks (18 disks of 18TB)? Something like 18 partitions on ssd or something else like this.

2- How is the best option to use for small files random IO 1MB files (millions of files on XFS backing systems - S3 Minio.io)?

Thanks for this amazing project!