[HPDD-discuss] Why my lustre 2.4 is faster on Reading and slow on write?

Hello, I am little bit puzzled my Reading is faster than Writing, should not be other way around? Writing on single OST is about 400MiB/s using Lustre. If I write directly to raid it brings 1200MiB/s and random 800MiB/s Could you please advise where to dig or tuneup? Thanks in advance Arman. tuned-admin My recent IOR test shows: mpirun -np 4 src/ior -a POSIX -r -w -b 32g -t 1m -o /lustre/arm2arm/IORFile -O lustreStripeCount=-1 -v -i 3 Summary of all tests: Operation Max(MiB) Min(MiB) Mean(MiB) StdDev Mean(s) Test# #Tasks tPN reps fPP reord reordoff reordrand seed segcnt blksiz xsize aggsize API RefNum write 343.27 177.23 287.06 77.67 502.04247 0 4 4 3 0 0 1 0 0 1 34359738368 1048576 137438953472 POSIX 0 read 788.68 768.17 776.53 8.79 168.81345 0 4 4 3 0 0 1 0 0 1 34359738368 1048576 137438953472 POSIX 0 the mds-survey shows good performance: thrhi=16 dir_count=16 file_count=200000 mds-survey Thu Aug 1 12:05:12 CEST 2013 /usr/bin/mds-survey from araid062 mdt 1 file 200000 dir 16 thr 16 create 33506.27 [25998.91,36998.41] lookup 790273.32 [790273.32,790273.32] md_getattr 474972.51 [474972.51,474972.51] setxattr 11483.39 [ 0.00,21999.03] destroy 73063.39 [63998.59,63998.59] done! My hardware is following: Raid box has a 24 SATA Disks(7200rpm with adaptec 6805controller raid6) ,DDR IB, 32GB Ram, 8core CPU. RaidBox1: mds/mdt+oss2 drbd | RaidBox2: mds/mdt(slave)+oss1 Each box has a sigle port DDR IBs. oss1, oss2- 34T - used 75% mdt: 92G - used 3% Software SL6.4, Lustre 2.4 kernel 2.6.32-358.6.2 tuned-adm active Current active profile: latency-performance Service tuned: enabled, running Service ktune: enabled, running