## KERNEL MEMORY
#
# Do not exceed your RAM size! Note available RAM is lowered by 500MB when
# using the USB or LiveCD distribution. You can increase kernel memory up to
# 1GB less than your physical RAM.
#
# if you exceed the limits of kernel memory, you may get a panic like this:
# panic: kmem_malloc(131072): kmem_map too small: <totalkmem> total allocated
#
vm.kmem_size="7g"
vm.kmem_size_max="8g"


## ZFS tunables

# ARC limits
# tune these in according with vm.kmem_size setting; you can increase it
# up to the value of vm.kmem_size minus 1GB.
#
# note: kernel memory size needs to be larger than maximum ARC size (arc_max)
# note: zfs uses more memory than just the ARC; don't make the ARC too big
#
vfs.zfs.arc_min="2g"
vfs.zfs.arc_max="3g"

# ARC metadata limits
# increase to cache more metadata (recommended if you have enough RAM)
#vfs.zfs.arc_meta_limit="128m"

# ZFS prefetch disable
# setting this value to 0 will force prefetching to be used even when
# ZFS considers it undesirable if you have <= 4GiB RAM or running 32-bit
#vfs.zfs.prefetch_disable="0"

# ZFS transaction groups (txg)
# ZFS is not unlike a transactional database in the sense that it processes
# your data in transaction groups. The bigger the txg is, the more data it
# can hold but also the longer flushing transaction groups will take.
# experiment with these values to improve temporary 'lags' or 'hangs'
# override maximum txg size in bytes
#vfs.zfs.txg.write_limit_override="0"
# target number of seconds a txg will be synced (tune this!)
#vfs.zfs.txg.synctime="5"
# maximum number of seconds a txg will be synced (tune this!)
#vfs.zfs.txg.timeout="30"

# vdev cache settings
# should be safe to tune; but be careful about your memory limits
#vfs.zfs.vdev.cache.bshift="16"
#vfs.zfs.vdev.cache.size="10m"
#vfs.zfs.vdev.cache.max="16384"

# vdev pending requests
# this manages the minimum/maximum of outstanding I/Os on the vdevs
# this should be safe to tune; best setting depends on your disks
# ssds may prefer higher settings
vfs.zfs.vdev.min_pending="1"
vfs.zfs.vdev.max_pending="2"

# other vdev settings
# I/O requests are aggregated up to this size
#vfs.zfs.vdev.aggregation_limit="131072"
# exponential I/O issue ramp-up rate
#vfs.zfs.vdev.ramp_rate="2"
# used for calculating I/O request deadline
#vfs.zfs.vdev.time_shift="6"

# disable BIO flushes
# disables metadata sync mode and uses async I/O without flushes
# ONLY USE FOR PERFORMANCE TESTING
#vfs.zfs.cache_flush_disable="1"

# disable ZIL (ZFS Intent Log)
# warning: disabling can sometimes improve performance, but you can lose data
# that was recently written if a crash or power interruption occurs.
# ONLY USE FOR PERFORMANCE TESTING
#vfs.zfs.zil_disable="1"

## other tuning
kern.maxfiles="950000"

## mandatory kernel modules (REQUIRED)
zfs_load="YES"
#geom_uzip_load="YES"
#tmpfs_load="YES"

## recommended kernel modules
ahci_load="YES"
siis_load="YES"

## optional kernel modules
#geom_md_load="YES"
#nullfs_load="YES"
#unionfs_load="YES"

# end #