Hi all, I have evaluated Fusion-io ioDrive duo (PCIe direct attached NAND flash memory storage) on the CentOS 5.4. The experimental result shows the write performance with multiple jobs (processes) on the ext3/ext4 filesystems is lower than that of XFS. The question I have is what is the cause of the ext3/ext4 performance limitation. I have measured the random write performance on several filesystems using fio benchmark (http://freshmeat.net/projects/fio/). My PC box has dual Intel Xeon W5590 3.33 GHz (8 cores), 48 GB memory, and Fusion-io ioDriveDuo (320 GB SLC). The XFS performance grows as the number of jobs increases. On the other hands, the ext3/ext4 do not. In the both cases, I mount filesystems with the "noatime" option only. The results are shown below: block size XFS XFS ext4 ext4 (1job) (8job) (1job) (8job) 1024 21 71 22 21 2048 40 144 42 40 4096 74 290 76 76 8192 131 635 133 131 16384 212 1029 219 215 32768 310 1169 326 316 65536 399 1236 374 374 131072 748 1332 718 676 262144 895 1336 902 804 524288 1000 1327 974 905 1048576 1100 1308 1136 995 2097152 1220 1276 1179 1082 4194304 1230 1233 1270 1149 8388608 1309 1233 1243 1188 (The unit is MB/s.) You can see the more detail information from here: http://code.google.com/p/pspacer/wiki/ioDriveDuo Any comments and suggestion will be welcome. If this list is not proper place to talk about this problem, can anyone tell me the proper one? Best regards, Ryousei