[LU-3293] Could Lustre support direct I/O？

• Type: Task
• Resolution: Unresolved
• Priority: Minor
• Environment: 4 OSTs
• Assignee: WC Triage
• Reporter: caibin

Description

I tested the performance with obdfilter-survey, the max performance is 732MB/s;

Result as follow：
[root@50:B3:42:00:00:F4 node]# nobjhi=1 thrhi=2 size=40960 case=disk sh obdfilter-survey
Tue May 7 15:52:33 CST 2013 Obdfilter-survey for case=disk from 50:B3:42:00:00:F4
ost 4 sz 167772160K rsz 1024K obj 4 thr 4 write 722.96 [ 143.90, 342.60] rewrite 732.23 [ 155.69, 205.75] read 790.50 [ 125.87, 228.77]
ost 4 sz 167772160K rsz 1024K obj 4 thr 8 write 712.76 [ 145.78, 193.74] rewrite 714.39 [ 159.78, 196.75] read 940.83 [ 197.79, 258.72]

I tested the performance with dd （oflag=direct） on the same devices, the max performance is 1038MB/s;

So I want to know if Lustrefs support direct mode?