I do not work for Joyent, but I've run a lot of SmartOS and I have opinions that I think are relevant (inline):
· Does joyent set “sync=disabled” on windows zvol’s? > I highly doubt it. Joyent hardware specs that I have seen are either all-SSD, or have SSD SLOG devices in the pool to ensure snappy ZFS synchronous writes. Changing that setting makes things "go faster" at the very real cost of opening up the potential for the guest VM to experience data corruption of the NTFS filesystem in the case of power-failure of the SmartOS host system. That is a tradeoff that you can make if you know for sure that you have other protections in place (For example if they are all thin-provisioned from a generic image, and user data are all either unimportant, backed up, or preserved with regular snapshotting, etc.). Joyent can't know that about the workloads in the JPC, so they depend on fast SLOGs, not playing fast and loose with customer data. > · Does joyent use “dedup=on” on cloud nodes? > I highly doubt this one as well. dedup has some serious drawbacks outside of some very specific use cases. They leverage thin provisioning more so than dedup. I do not recommend use of dedup without lots of research into the consequences and serious testing. > · Is there a list of “best practices” options to set on windows > VM’s to get the most performance? Taking into account that the ZVOL will > have ntfs on top of it? > I'm not sure. Certainly getting the virtio drivers working correctly for the disk helps. > · Is there a performance hit using thin-provisioned ZVOL’s? > I'm pretty sure it's the opposite and that the ARC is able to detect that everyone is using the same block and only needs to cache one. > · Is LZ4 compression okay on a ZVOL dataset? Is there a > performance impact to the VM’s or the GZ? > My experience has generally been that LZ4 is an all-around win. Your CPUs can do the LZ4 compression so fast and the reduction of how much needs to actually land on disk, combined with the improved disk utilization make it something I generally enable by default. > · Are there any performance options that ive missed here such as > record size that could impact performance positively (or negatively)? > By default the zvol's get the 8k block size. At this time I don't think that SmartOS advertises an 8k block size to the guest. It's possible that there could be some interesting performance analysis that one could to tweaking both the zvol block size and the block size advertised by QEMU to the guest, but I have not done so. I hope that someone from Joyent will weigh in on anything that I've either gotten wrong, or where their recommendations are different from mine. -Nahum ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
