Hi @Jian Hong Lek ,
SharePoint 2016 supports increasing the size of a content database up to 4 TB, provided that certain requirements are met, such as disk subsystem performance and high availability plans. However, it is strongly recommended to limit the size of content databases to 200 GB, except when specific usage scenarios and conditions support larger sizes. In this case, the customer's SharePoint site is already at 700 GB, which is well beyond the recommended limit.
To address this, it is recommended to split the content database into multiple databases, rather than increasing the size of the existing database. This can be done by moving site collections to different databases. It is suggested that for ease of backup and restore, individual site collections within a content database be limited to 100 GB.
It is also recommended to proactively manage the growth of data and log files by pre-growing all data and log files to their expected final size, enabling autogrowth, and setting the database autogrowth value to a fixed number of megabytes instead of a percentage.
For your references:
Hope this is helpful.
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