Performance issues with 8.0 ZFS and sendfile/lighttpd

[Miroslav Lachman]

Michael Loftis 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.

iostat and zpool was posted in another message.
gstat or systat -vm is showing about 60% busy disk and even if there is 
high IO on the disks, lighttpd serving the same content from gmirrored 
UFS2 with gjournal and not in jail is serving three times more clients 
and bandwidth without this drop down behavior.
Both machines are Sun Fire X2100 M2 with SATA disks.

Miroslav Lachman