On 09/01/14 01:39 AM, Digimer wrote:
Hi all,
I've been trying to do some tuning with DRBD. The network interface
sustains 1.225 GB/sec tested with iperf (multiple tests, hf and fd). The
disks themselves sustain 1.2 GB/sec sequential writes (975 GB write via
'dd if=/dev/zero of=/dev/sda5 bs=4M), tested repeatedly and on both
nodes. The storage array is an 8-disk (146 GB 15krpm 2.5" SAS disks on
an LSI RAID controller with a 2208 ASIC).
<snip>
Answering some of my own questions; sharing what I've done/tested;
I saw (http://www.drbd.org/users-guide/ch-benchmark.html):
====
For freshly enabled DRBD devices, it is normal to see significantly
reduced performance on the first dd run. This is due to the Activity Log
being "cold"
====
So I am going to let the initial sync finish and try again.
I also noticed that I had enabled 'data-integrity-alg' and re-enabled
'disk-flushes no;' and 'md-flushes no;'. I've disabled these and it's
already dd'ing at ~650 MB/sec. This is still half of what the
storage/network can handle, but it's a mighty scene better than before. :)
I'll post more as I experiment/learn. In the meantime, I would very much
love to hear feedback, specially from folks with experience tuning for
LSI-based controllers and 10 gbps ethernet networks.
Thanks!
--
Digimer
Papers and Projects: https://alteeve.ca/w/
What if the cure for cancer is trapped in the mind of a person without
access to education?
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