I tried ext4 vs. xfs doing 4 parallel 2G IO writes in 1M units to 4 different subdirectories of the root of the filesystem: http://people.redhat.com/esandeen/seekwatcher/ext4_4_threads.png http://people.redhat.com/esandeen/seekwatcher/xfs_4_threads.png http://people.redhat.com/esandeen/seekwatcher/ext4_xfs_4_threads.png and then read them back sequentially: http://people.redhat.com/esandeen/seekwatcher/ext4_4_threads_read.png http://people.redhat.com/esandeen/seekwatcher/xfs_4_threads_read.png http://people.redhat.com/esandeen/seekwatcher/ext4_xfs_4_read_threads.png At the end of the write, ext4 had on the order of 400 extents/file, xfs had on the order of 30 extents/file. It's clear especially from the read graph that ext4 is interleaving the 4 files, in about 5M chunks on average. Throughput seems comparable between ext4 & xfs nonetheless. Again this was on a decent HW raid so seek penalties are probably not too bad. -Eric - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
