Help! I have four servers with 3x drive bays and have them populated with either 2x Samsung SM863 or 2x Intel S3610. The drives are set up as a ZFS mirrored vdev with both ROOT and data being on the pair. One bay is open on each server. Normally I/O load on each server is low - iowait is negligible. However, when doing a storage migration to those servers, iowait spikes and things go south - the VMs on the boxes go to 99% IOWAIT, the server itself isn't updating properly to the cluster (pvestatd fighting for I/O writes?), and it's a mess until the migration finishes and things catch up. My question is how to best address this given my limited options for adding drives? Would it be better to add a ZIL cache drive, or to redo the systems so ROOT and data are on separate SSDs? Permanent network storage isn't currently an option. Thanks!