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[ovs-dev,RFC,0/7] Fast OVSDB resync after restart or failover.

Message ID 1548371481-109219-1-git-send-email-hzhou8@ebay.com
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Series Fast OVSDB resync after restart or failover. | expand

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Han Zhou Jan. 24, 2019, 11:11 p.m. UTC 
In scalability test with ovn-scale-test, ovsdb-server SB load is not a
problem at least with 1k HVs. However, if we restart the ovsdb-server,
depending on the number of HVs and scale of logical objects, e.g. the
number of logical ports, ovsdb-server of SB become an obvious bottleneck.

In our test with 1k HVs and 20k logical ports (200 lport * 100 lswitches
connected by one single logical router). Restarting ovsdb-server of SB
resulted in 100% CPU of ovsdb-server for more than 1 hour. All HVs (and
northd) are reconnecting and resyncing the big amount of data at the same
time.

Similar problem would happen in failover scenario. With active-active
cluster, the problem can be aleviated slightly, because only 1/3 (assuming
it is 3-node cluster) of the HVs will need to resync data from new servers,
but it is still a serious problem.

For detailed discussions for the problem and solutions, see:
https://mail.openvswitch.org/pipermail/ovs-discuss/2018-October/047591.html

The patches implements the proposal in that discussion. It introduces
a new method monitor_cond_since to enable client to request changes that
happened after a specific point so that the data has been cached already
in client are not re-transfered.

The current patches supports all 3 modes of ovsdb-server, but only clustered
mode can benefit from it, since it is the only one that supports transaction
id out of the box.

Han Zhou (7):
  ovsdb-client.c: fix typo
  ovsdb_monitor: Fix style of prototypes.
  ovsdb-monitor: Refactor ovsdb monitor implementation.
  ovsdb-server: Transaction history tracking.
  ovsdb-monitor: Support monitor_cond_since.
  ovsdb-idl.c: Support monitor_cond_since method in C IDL.
  ovsdb-idl.c: Fast resync from server when connection reset.

 Documentation/ref/ovsdb-server.7.rst |  78 +++++-
 lib/ovsdb-idl.c                      | 229 ++++++++++++++----
 ovsdb/jsonrpc-server.c               | 101 ++++++--
 ovsdb/monitor.c                      | 458 ++++++++++++++++++++++-------------
 ovsdb/monitor.h                      |  78 +++---
 ovsdb/ovsdb-client.c                 | 106 +++++++-
 ovsdb/ovsdb-server.c                 |   8 +
 ovsdb/ovsdb.h                        |  10 +
 ovsdb/transaction.c                  | 103 +++++++-
 ovsdb/transaction.h                  |   3 +
 tests/ovsdb-monitor.at               | 294 ++++++++++++++++++++++
 11 files changed, 1181 insertions(+), 287 deletions(-)