[Lustre-discuss] Slow warnings

[Scott Atchley]

Hi all,

I am testing with MXLND. My setup is very simple. I have one MGS/MDT,  
one OST, and one client. All are running RHEL5.3. The OST is using a  
loopback device on the internal disk which is capable of ~70 MB/s.

I am running 10 dd in parallel which send 1 GB each and MXLND should  
be able to send the data ~1,100 MB/s. The machine has 8 GB of memory.  
Before the dds complete, free memory drops to about 32 MB. Everything  
completes, but Lustre posts the following to dmesg:

Lustre: 4227:0:(filter_io_26.c:641:filter_commitrw_write()) lustre- 
OST0000: slow i_mutex 30s
Lustre: 4222:0:(lustre_fsfilt.h:320:fsfilt_commit_wait()) lustre- 
OST0000: slow journal start 30s
Lustre: 4222:0:(filter_io_26.c:724:filter_commitrw_write()) lustre- 
OST0000: slow commitrw commit 30s
Lustre: 4242:0:(filter_io_26.c:706:filter_commitrw_write()) lustre- 
OST0000: slow direct_io 30s
Lustre: 4242:0:(filter_io_26.c:706:filter_commitrw_write()) Skipped 4  
previous similar messages

Should I be concerned or is this normal?

Scott