AFS Performance / ZFS

Hi,

iam testing a box with FreeNAS  (BSD) and ZFS. On this box i use
virtualized byhve guest as afs server.

The box includes SAS drives (12G/s) on HBA (12G/s). I created some vice
partitions for the afs server guest and connect them with ahci. If

For ZFS pool which contains the vice partitions:

- atime and  deduplication are off

- lz4 compression is on

The afs server parameters:

- udp size is set to 2MB and 8MB for test

- afs sync is set to "never", zfs sync is enabled

From afs client (desktop box, 1GE) to virtual afs server guest there is
1GE ethernet connection. If i test this connection with iperf i get
nearly 1GE test data speed.

If it test on client side with dd and create a file in the afs path i
get about 25 MB/s (200 MBit/s) with memcache and disk cache.

if i dd with oflag=direct to the unmounted  afs vicepa partition device
(/dev/sdX) in the afs server guest system then i get about 1 GBbyte/s
which nears to 12 Gbit/s of SAS drive/ HBA speed.


Any ideas why afs speed is only about 25 MByte/s ? Maybe i have to
adjust another afs server parameter ?


Andreas