UFS vs. ZFS inside bhyve hosted on ZFS

[Paul Vixie]

Russell L. Carter wrote:
> ...
> So I am wondering if UFS in the -current guest might be better
> overall. I can certainly do a multiple hour experiment, installing
> a new guest with UFS root, but since I am new to this, perhaps there is
> conventional wisdom about ZFS vs. UFS in the guest? Maybe UFS in the
> guest requires less cpu resources from the host? Or not?

i think you should do that experiment and share your results here.

my similar experiment did not involve bhyve. i make a zvol and put a ufs 
inside, and mounted that. for writing, it was so much faster than raw 
zfs, that i wondered if i should start migrating other things to it. as 
two examples, postgres servers and MH "Mail" directories go really 
really fast in ufs-on-zvol compared to zfs.

all my bhyve's are ufs, and their system disks are host zvols, not host 
zfs files made with "truncate". i admit that this was superstition on my 
part, but it's served me very well. one of my guests even expanded his 
bhyve file systems using geom and tunefs, after i made his zvol bigger. 
so, there's not much downside that i've seen.

-- 
P Vixie