Consider the following scenario:
You initiate a full/incremental crawl of the content source(s) in your SharePoint 2010 environment. Once the crawl begins, you find that the Crawl Store database (e.g. something such as 'SSA_CrawlStoreDB') for the Search Service Application (SSA) begins to grow causing the SQL Server to run out of disk space for either the database or transaction log directory. In this situation, the crawl will appear stuck in a 'Crawling' state. If an attempt is made to stop the crawl, the status will appear stuck in a 'Stopping' state. Additionally, in this disk starved state, the SQL Server may experience degraded performance (particularly if the disk space for TempDB is also impacted).
You initiate a full/incremental crawl of the content source(s) in your SharePoint 2010 environment. Once the crawl begins, you find that the Crawl Store database (e.g. something such as 'SSA_CrawlStoreDB') for the Search Service Application (SSA) begins to grow causing the SQL Server to run out of disk space for either the database or transaction log directory. In this situation, the crawl will appear stuck in a 'Crawling' state. If an attempt is made to stop the crawl, the status will appear stuck in a 'Stopping' state. Additionally, in this disk starved state, the SQL Server may experience degraded performance (particularly if the disk space for TempDB is also impacted).