On 2012-01-19 15:19, Xin Li wrote:
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On 01/19/12 13:22, Matt Connor wrote:
On 19.01.2012 13:15, Nick Sayer wrote:
I have a VPS at rootbsd.net, and have been running 8.2-RELEASE
with a XENHVM kernel with a patch to fix the 'do something smart'
panic in if_xn. I fetched the 9.0-RELEASE source tree and built a
kernel to try and it worked without any muss or fuss. I did the
rest of the upgrade and it's working just fine, so far as I can
tell.

And there was much
rejoicing._______________________________________________

Same here at ssdnodes.com - we pulled the new source tree, rebuilt
with our modified XENHVM and haven't had any issues so far.

We had many tweaks in /etc/sysctl.conf to improve throughput for
the 8.2-RELEASE, the 9.0-RELEASE systems still remained snappy
after the tweaks were removed.

What kinds of tweaks are needed? (i.e. should we make them the defaults?)


The tweaks were only "needed" because we were trying to achieve a specific network throughput in our particular workload (read: turning the knob all the way until it broke off). These values are no longer in production on version 9.0-RELEASE, I highly recommend these never become default.

For your amusement, I've included the values below:


-/boot/loader.conf
# ZFS tuning parameters
# We're running on top of a hardware battery-backed RAID controller, therefore disable cache flush
 vfs.zfs.cache_flush_disable=1
 vfs.zfs.prefetch_disable=1
# Recommends not setting a kmem limit and increasing arc
# http://www.listshow.net/201005/freebsd-fs/9744-very-bad-zfs-performance-on-fresh-freebsd-8-installation.html
 vfs.zfs.arc_min="512M"
 vfs.zfs.arc_max="3584M"
# Drive tweaks
 vfs.zfs.vdev.min_pending=2
 vfs.zfs.vdev.max_pending=30
 vfs.zfs.txg.timeout=5


-/etc/sysctl.conf
# not having this will cause the system to be very sluggish during file I/O as well as hanging during the nightly cron jobs
vfs.ufs.dirhash_maxmem=64777216

vfs.write_behind=0
vfs.lorunningspace=1048576
vfs.hirunningspace=8388608

# Kernel Tuning
kern.ipc.maxsockbuf=16777216
net.inet.tcp.rfc1323=1
kern.ipc.somaxconn=2048

# Experimental
kern.maxfilesperproc=64768
kern.maxvnodes=800000
net.local.stream.recvspace=65536
kern.maxfiles=65536
net.inet.udp.maxdgram=57344
net.inet.tcp.mssdflt=1460
net.inet.tcp.sendbuf_max=67108864
net.inet.tcp.recvbuf_max=67108864
net.inet.tcp.inflight.enable=0
net.inet.tcp.sendspace=262144
net.inet.tcp.recvspace=262144
net.inet.udp.recvspace=262144
net.inet.tcp.sack.enable=1
net.inet.tcp.path_mtu_discovery=1
net.inet.tcp.sendbuf_auto=1
net.inet.tcp.sendbuf_inc=16384
net.inet.tcp.recvbuf_auto=1
net.inet.tcp.recvbuf_inc=524288
net.inet.tcp.hostcache.expire=1
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