Here are my answers, hope it will help solve this issue, thanks. Recap: dpkg kibana on ext4 over a nbd device takes 10 minutes with xfs it's only 30s. with ext4 no extends only 30s. kernels : 4.5.7 has this issue as older kernel like 4.4.34 The issue is also when nbd client & server run on same host How small are the files? here is the histogram of file sizes : http://pasteboard.co/6HC3nKyk2.png We can see 5000 files around 512 Bytes. dpkg using fallocate() ? Yes, there are 16044 calls by the same process what are these uninitialized extents ? Cheers, Renaud -- 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
