On Mon, 2018-07-16 at 09:27 -0400, Cole Robinson wrote: > On 07/15/2018 11:47 AM, Richard W.M. Jones wrote: > > On Fri, Jul 13, 2018 at 04:05:42PM +0200, Mikolaj Izdebski wrote: > > > On 07/12/2018 10:17 PM, Richard W.M. Jones wrote: > > > > Does each build start with its own fresh VM? Do you care about the > > > > data in that build VM if either qemu or the host crashes? If the > > > > answers are 'Yes' and 'No' respectively to these questions then IMHO > > > > this is the ideal situation for cache=unsafe. > > > > > > The answers are 'No' and 'Not much'. > > > > > > 1. VMs are installed once and are running for week/months until they are > > > reinstalled. In the meantime guests and hosts are rebooted during > > > routine maintenance, to apply updates. > > > > In this case my preferred advice would be: DO NOT use cache=unsafe. > > > > We've only tested scenarios for very short-lived build or temporary > > VMs (for example when I was building RISC-V packages before we had > > Koji, I used a script which created a VM per build and there it made > > sense to use cache=unsafe). > > > > I do not think it's a good idea to be using this for VMs which are in > > any way long-lived as there could be unforeseen side effects which I'm > > not aware of and certainly have never tested. > > > > One other datapoint is that I _think_ openqa uses cache=unsafe, which is > used for Fedora automated install testing. I'm basing this largely on > cache=unsafe in the openqa sources.
That's mostly true, I think, except when doing multipath testing (where it uses cache=none instead). However, openQA very much meets the definition of 'short-lived / temporary' VMs - each openQA 'job' uses a new VM, so the longest any one ever lasts is 2 hours (the hard limit on an openQA job's lifetime). It also uses fresh disk images each time (even when using a pre-created base disk image, it doesn't use it directly but creates new scratch images based on the base image). I don't know whether this is true of the Koji builder VMs. -- Adam Williamson Fedora QA Community Monkey IRC: adamw | Twitter: AdamW_Fedora | XMPP: adamw AT happyassassin . net http://www.happyassassin.net _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/AMCPPS23B4F6Y5AON662I7GSGUL3MOSM/
