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Hello,
On Mon, 2 Apr 2018, Vincent Bernat wrote:
> Based on Google's Maglev algorithm [1][2], this scheduler builds a
> lookup table in a way disruption is minimized when a change
> occurs. This helps in case of active/active setup without
> synchronization. Like for classic source hashing, this lookup table is
> used to assign connections to a real server.
>
> Both source address and port are used to compute the hash (unlike sh
> where this is optional).
>
> Weights are correctly handled. Unlike sh, servers with a weight of 0
> are considered as absent. Also, unlike sh, when a server becomes
> unavailable due to a threshold, no fallback is possible: doing so
> would seriously impair the the usefulness of using a consistent hash.
>
> There is a small hack to detect when all real servers have a weight of
> 0. It relies on the fact it is not possible for the weight of a real
> server to change during the execution of the assignment. I believe
> this is the case as modifications through netlink are subject to a
> mutex, but the use of atomic_read() is unsettling.
>
> The value of 65537 for the hash table size is currently not modifiable
> at compile-time. This is the value suggested in the Maglev
> paper. Another possible value is 257 (for small tests) and 655373 (for
> very large setups).
>
> [1]: https://research.google.com/pubs/pub44824.html
> [2]:
> https://blog.acolyer.org/2016/03/21/maglev-a-fast-and-reliable-software-network-load-balancer/
Sorry to say it but may be you missed the discussion
on lvs-devel about the new MH scheduler implemented by Inju Song:
https://www.spinics.net/lists/lvs-devel/msg04928.html
http://archive.linuxvirtualserver.org/html/lvs-devel/2018-03/msg00023.html
In the last 6 months we fixed all issues and I acked
v4 just yesterday:
http://archive.linuxvirtualserver.org/html/lvs-devel/2018-04/msg00003.html
This scheduler supports:
- tables with different size (prime): IP_VS_MH_TAB_INDEX
- gcd of weights: ip_vs_mh_gcd_weight
- shifted weights: ip_vs_mh_shift_weight
- weight can be changed any time
> Signed-off-by: Vincent Bernat <vincent@xxxxxxxxx>
> ---
> include/net/ip_vs.h | 27 ++++
> net/netfilter/ipvs/Kconfig | 13 ++
> net/netfilter/ipvs/Makefile | 1 +
> net/netfilter/ipvs/ip_vs_csh.c | 339
> +++++++++++++++++++++++++++++++++++++++++
> net/netfilter/ipvs/ip_vs_sh.c | 32 +---
> 5 files changed, 381 insertions(+), 31 deletions(-)
> create mode 100644 net/netfilter/ipvs/ip_vs_csh.c
Regards
--
Julian Anastasov <ja@xxxxxx>
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