Disk Cache Settings Recommendations

[mygeeknc]

Good afternoon everyone. I'm wanting to get others opinions on what the best cache mode is for our particular setup.

Our setup is a cluster of 6 hosts with a single SSD for the proxmox install and then the VM's have a Synology RS3614xs+ for storage over NFS with a pair of SSDs for cache. Our hard disk format is qcow2.

According to the wiki, cache=none is the best option for this format and our setup. Is that still true?

Right now we have them set to writeback.

Thanks!

 

[manu]

Setting a cache mode is a tradeoff between speed and data safety.
In your case Yes, cache=none is the best !

Quoting this presentation:
http://events.linuxfoundation.org/sites/events/files/slides/CloudOpen2013_Khoa_Huynh_v3.pdf

cache = none is great for write- intensive workloads or workloads involving NFS remote storage (hosts page cache disable and disk write cache enabled)