Best practice for SSD versus HDD for VM's

[louyo]

I am moving Domain Controller/File Server and another VM to new hardware running ESXi 7. I have 2 HDD RAID 1 VD's and 1 SSD RAID 1 VD. I need to put the database for an application on the SSD but am  wondering about putting the DC/FS on the same SSD with the bulk of the remaining data on one of the HDD's. In all, there are 5 drives on the DC (WS 2016 Essentials). The second VM (W10 acting as a "server" for an AS400) will be on one of the HDD datastores. 

Is there a best practice about putting VM OSes on a SSD?

Thanks.

[a_p_ · Accepted solution]

Hard to say what to place on which tier, without knowing performance requirements/details.

Anyway, some thoughts:

• with WS Essentials, the environment is likely not very large
• assuming that you use a RAID controller with BBU option, performance with HDDs isn't too bad anyway (likely sufficient for e.g. file services)
• what I'd probably place on SSDs - depending on available space - is the DC's C: drive (which likely contains the AD), Exchange, DBs, and other high I/O demanding applications

André

[louyo]

Thank you Andre, that is what I wanted to do. In fact, I moved the C drive from the HDD datastore to the SSD datastore a couple of days ago. The server is not yet in production. I was a little concerned about wear leveling and such. The SSD's are 600 GB so lots of spare room. The C drive is only 120 GB (thick) with 80 GB used, so was easy to move.

For the time being, I will leave the 2 files (vmdk and flat vmdk) on the HDD and keep the old vmx file in case I decide to move it back. Will create a script to keep it current if I decide to use it as a backup.

Thanks again, your input is always appreciated.

Lou (Andre is my middle name)