On 05/18/2016 03:40 PM, Ondrej Moris wrote: > > Testing with KVM > ---------------- > KVM is now used to emulate network under test. This approach is slow > because of various reasons (not only related to KVM): slow boot of > guests, sanity checks (eg. checking that something is not reachable > means waiting for timeout), transmogrification slow-down, reboots of > guests between subsequent tests need to clean-up network stacks. KVM > approach does not scale well, it works fine for 1-3 network nodes but > fails badly for 100. Parallel test execution does not fit into KVM by > the same principle. The only non-network shared directory for KVM is > represented by 9P filesystem which is rather slow, seemingly not > maintained anymore and missing completely in RHEL. Avoiding 9P means > using network between host and guests (eg. NFS) which might be fragile > and potential source of problems. Last but no least, KVM seems to losing > drive. >
I dug into 9P replacement a bit more during the last days trying to find a way how to avoid network-related solution. I got an idea to use some smarter filesystem with separate journals and simultaneous mounts and tried gfs2. It is widely supported in linux distributions. I played with it for a while and it is possible to create gfs2 filesystem in a file on host, mount it via loopback device and add it to guests as a shared raw storage. Guests then mount it as gfs2, whoever mounts it has its own journal, no network is involved, but... apparently a cluster is needed to make gfs2 work and deploying a cluster is overcomplicated, number of nodes is very limited (<=16) and it needs network in the first place. There are no other non-network options. We can try to replace 9P by NFS now. I will be traveling until June 7, but one of my colleagues will be working on that. Then we can focus on KVM performance fine-tuning of issues Antony described earlier in this thread. And I will get back to Docker afterwards. -- Ondrej _______________________________________________ Swan-dev mailing list [email protected] https://lists.libreswan.org/mailman/listinfo/swan-dev
