search for: backpresure

ZFS works really stable on FreeBSD, but I''m biggest problem is how to control ZFS memory usage. I''ve no idea how to leash that beast. FreeBSD has a backpresure mechanism. I can register my function so it will be called when there are memory problems, which I do. I using it for ARC layer. Even with this in place under heavy load the kernel panics, because memory with KM_SLEEP cannot be allocated. Here are some statistics of memory usage when the panic occ...