Performance issues with 8.0 ZFS and sendfile/lighttpd

[Michael Loftis]

--On Monday, November 02, 2009 12:06 PM +0100 Miroslav Lachman 
<000.fbsd at quip.cz> wrote:

> I have more strange issue with Lighttpd in jail on top of ZFS. Lighttpd
> is serving static content (mp3 downloads thru flash player). Is runs fine
> for relatively small number of parallel clients with bandwidth about 30
> Mbps, but after some number of clients is reached (about 50-60 parallel
> clients) the throughput drops down to 6 Mbps.
>
> I can server hundereds of clients on same HW using Lighttpd not in jail
> and UFS2 with gjournal instead of ZFS reaching 100 Mbps (maybe more).
>
> I don't know if it is ZFS or Jail issue.


Check iostat 5 or zpool iostat 5 -- I bet you're disk thrashing when you 
start to slow down.