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The maximum effective value is 919 * (available on-disk activity log ring buffer area / 4kB -1), which is up to 6433 (including 25 GiB or more data) in the default 32KB ring buffer. It's a good idea to keep the size of the activity log within an amount where the backend storage and replication links can be resynchronized in about 5 minutes.
Changing the size of al-extents requires a resource down.
al-updates {yes | no}
With this parameter, the activity log can be turned off entirely (see the al-extents parameter). This will speed up writes because fewer meta-data writes will be necessary, but the entire device needs to be resynchronized opon recovery of a failed primary node. The default value for al-updates is yes.
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