On Thu, Jan 19, 2012 at 9:06 PM, Matt Connor <b...@xerq.net> wrote:

> On 2012-01-19 15:19, Xin Li wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> 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<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


Any of these recommended for those of us who aren't rushing to leave 8.2
yet?
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