Getting a lot of "Did not write session for ID..."

[fredrikjahr]

Example:
Did not write session for ID 0m8vk5mqaq33dqok3sqdbfk5h1: another process took the lock.

How can I avoid this?

This is my settings:

    <redis_session>                       <!-- All options seen here are the defaults -->
        <host>127.0.0.1</host>            <!-- Specify an absolute path if using a unix socket -->
        <port>6379</port>
        <password></password>             <!-- Specify if your Redis server requires authentication -->
        <timeout>2.5</timeout>            <!-- This is the Redis connection timeout, not the locking timeout -->
        <persistent></persistent>         <!-- Specify unique string to enable persistent connections. E.g.: sess-db0; bugs with phpredis and php-fpm are known: https://github.com/nicolasff/phpredis/issues/70 -->
        <db>0</db>                        <!-- Redis database number; protection from accidental loss is improved by using a unique DB number for sessions -->
        <compression_threshold>2048</compression_threshold>  <!-- Set to 0 to disable compression (recommended when suhosin.session.encrypt=on); known bug with strings over 64k: https://github.com/colinmollenhour/Cm_Cache_Backend_Redis/issues/18 -->
        <compression_lib>gzip</compression_lib>              <!-- gzip, lzf, lz4 or snappy -->
        <log_level>7</log_level>               <!-- 0 (emergency: system is unusable), 4 (warning; additional information, recommended), 5 (notice: normal but significant condition), 6 (info: informational messages), 7 (debug: the most information for development/testing) -->
        <max_concurrency>6</max_concurrency>                 <!-- maximum number of processes that can wait for a lock on one session; for large production clusters, set this to at least 10% of the number of PHP processes -->
        <break_after_frontend>5</break_after_frontend>       <!-- seconds to wait for a session lock in the frontend; not as critical as admin -->
        <break_after_adminhtml>30</break_after_adminhtml>
        <first_lifetime>600</first_lifetime>                 <!-- Lifetime of session for non-bots on the first write. 0 to disable -->
        <bot_first_lifetime>60</bot_first_lifetime>          <!-- Lifetime of session for bots on the first write. 0 to disable -->
        <bot_lifetime>7200</bot_lifetime>                    <!-- Lifetime of session for bots on subsequent writes. 0 to disable -->
        <disable_locking>0</disable_locking>                 <!-- Disable session locking entirely. -->
        <min_lifetime>60</min_lifetime>                      <!-- Set the minimum session lifetime -->
        <max_lifetime>2592000</max_lifetime>                 <!-- Set the maximum session lifetime -->
    </redis_session>    

[colinmollenhour]

Increase break_after_* or disable locking or ignore the errors if they seem to be for legitimate reasons.