[Exim] spool over NFS?

Apologies from starting a new thread - my last one kinda died :(

I've read differing opinions on this issue... Can I have a quick 'yes' or 'no'
answer - is it safe to have a dedicated mount point for a mail spool per server
over NFS (we use a NetApp FAS270's) using Exim 4.34? Will it be safe for NFS
locking etc.?

I am more than happy with NFS performance/reliability with our NetApp and I
trust the NetApp filer more than I trust local SCSI disks (mirrored or not!).
In 5 years we have never had a NetApp filer fail on us...