From 1746672e91ee03cdc4ca935acbda3fc26b0c49a4 Mon Sep 17 00:00:00 2001 From: Clay Gerrard Date: Thu, 28 Jan 2021 13:51:01 -0600 Subject: [PATCH] Update Memcached Considerations docs Change-Id: I561ca419104bfb4b64affc477aac53a2fb98137b --- doc/source/deployment_guide.rst | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/doc/source/deployment_guide.rst b/doc/source/deployment_guide.rst index f6fdfbd2a1..5188bb8952 100644 --- a/doc/source/deployment_guide.rst +++ b/doc/source/deployment_guide.rst @@ -498,8 +498,17 @@ primary entry point to many container requests, as it provides the list of shard To take load off the root container Swift by default caches the list of shards returned. As the number of shards for a root container grows to more than 3k the memcache default max -size of 1MB can be reached. Care is needed to keep an eye on the current value or resize it -to something like 5MB. +size of 1MB can be reached. + +If you over-run your max configured memcache size you'll see messages like:: + + Error setting value in memcached: 127.0.0.1:11211: SERVER_ERROR object too large for cache + +When you see these messages your root containers are getting hammered and +probably returning 503 reponses to clients. Override the default 1MB limit to +5MB with something like:: + + /usr/bin/memcached -I 5000000 ... Memcache has a ``stats sizes`` option that can point out the current size usage. As this reaches the current max an increase might be in order::