9.0-RELEASE success

Matt Connor bsd at xerq.net
Fri Jan 20 02:06:57 UTC 2012


On 2012-01-19 15:19, Xin Li wrote:
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> Hash: SHA1
>
> 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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