Thanks. Some good run-throughs looking around. I'd probally not go the FeeBSD route as I'm wandering too far from linux - but, it should not be that different. Some good articles out there.

Thanks. Perhaps a clean -current install will work well, as the install on _this_ machine is more than a little complex.

Thanks all. It looks like there are some good options.
NetBSD/Alipne/OpenSUSE + Xen for one way.
VirtualBox as the other - if I try this on Slackware I'll do it on a clean(ish) install.

I'll likely give both a go.

From looking on the web at xcp-ng and Proxmox these look interesting but are more aimed at servers. Intesting for later but I'll not go that route right now.

Thanks,

Pete

I'm somewhat behind the times - for me, server-side is Slackware 14.1 running Xen 4.5.1 (from SlackBuilds). This is at work but at a very small company. I installed it in 2015 and since then I only switched the host machine once (but kept the same software configuration). It runs 5 domU instances (4 Slackware 14.1 and 1 Windows 7). On occasion I start a NetBSD or another Windows instance for different needs/experiments.

All regular domU instances are using partitions on a RAID1 array - I think it gives better performance than regular files; I don't have guest (storage) snapshots, but I have good enough backups.

My main reason was that it's free and feels "light" on resources. It also feels simpler/better documented than other options. I like its configuration files and it fits quite well with Slackware.

I should move to newer versions (both Xen and Slackware) but all the virtualized machines are in my administration so I don't worry too much about security issues regarding guest-host interactions (and of course, time is always lacking). The main reason for virtualization was energy savings (power/cooling). It's easier to cool one big..-ish computer than it was to power and cool 5. Not to mention less hardware issues. The only server still on bare metal is the company fileserver (also Slackware 14.1/Samba). The performance for those under Xen feels ok, but there aren't heavy loads involved.

Side-note: The Windows 7 installation functions as license server for an accounting package. This required qemu which takes around 15% of CPU on dom0 by itself, despite the guest not doing much.

Another thing I like about XEN was that it helps with maintenance - in fact I did a somewhat unorthodox move of all guests from one host to another using drbd (shared storage) at one point; this still resulted in 1-2 minutes of downtime because in testing I couldn't get it to move running guests reliably between hosts. Shutting down the guests on one host and starting them up on the other worked fine, though.

my system (laptop):
i7-4810MQ
RAM 32GB
2xSSD (Samsung)
video hybrid with host intel video in use
host OS Slackware-current with latest kernels (just for fun, does not matter for VM)
VM VirtualBox 5.x (from Oracle site - just works better)
tested VirtualBox 6.x but disk access performance below 5.x
current guests:
Slackware-current (for safe testing upgrades)
OpenIndiana
MX Linux (some software accesibility)
Funtoo (getting rid of this - too much problems with updates)
FreeBSD (my first personal OS since mid 90')
Windows 8.1 (photo editing software)

all work well: sound is available and works with youtube/music (no stuttering), youtube/movies visible sound delay
video no issues

hope this will help