Actually, no. With btrfs, currently it assigns a per-fs backing device to each inode. So for that particular case, you have just a single bdi flusher thread running even for the 10 disks.
Posted Feb 10, 2011 8:25 UTC (Thu) by bergwolf (subscriber, #55931)
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Then why does per-bdi flusher improves that much performance for btrfs? If the key idea is *per-bdi*, there is little difference for btrfs. But where does the performance come from?