Hi all, I found that when I create a file, the number of inodes on OST does not increase. Let's see the following experiment: [root@client lustre]# lfs df -i UUID Inodes IUsed IFree IUse% Mounted on data-MDT0000_UUID 524288 3428 520860 1% /lustre[MDT:0] data-OST0000_UUID 393216 2398 390818 1% /lustre[OST:0] data-OST0001_UUID 393216 2398 390818 1% /lustre[OST:1] filesystem summary: 524288 3428 520860 1% /lustre [root@client lustre]# dd if=/dev/zero of=/lustre/file12 bs=1M count=1000 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 46.4868 s, 22.6 MB/s [root@client lustre]# lfs df -i UUID Inodes IUsed IFree IUse% Mounted on data-MDT0000_UUID 524288 3429 520859 1% /lustre[MDT:0] data-OST0000_UUID 393216 2398 390818 1% /lustre[OST:0] data-OST0001_UUID 393216 2398 390818 1% /lustre[OST:1] filesystem summary: 524288 3429 520859 1% /lustre You can see the number of inodes on MDT is increased by 1. But the number of inodes on OST keep unchanged. According to Lustre Manual, the inodes on OST should increase. "Each time a file is created on a Lustre file system, it consumes one inode on the MDT and one inode for each OST object over which the file is striped. " Anyone knows why? Thanks very much. Regards, Patrick