Hi @Rumi ,
Based on your description, when users try to search items ,the performance is well. The issue only occurs when you try to start a crawl, so I would like to confirm some information about your farm.
- Have you observed that many new files are created right after you added the users. A huge increase of new documents may cause performance issues on crawling.
- Please have a check on the crawl log to see if there is any error.
- Would you like to provide more detailed information about error messages in your ULS log?
4.What is the spec of search servers, how large is the RAM?
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