Merge pull request #3485 from meilisearch/update-ram-storage-recommendations

Update RAM and disk recommendations in storage docs

Author: Kerollmops

learn/engine/storage.mdx

@@ -24,7 +24,9 @@ LMDB stores its data in a [memory-mapped file](https://en.wikipedia.org/wiki/Mem
 
 All documents stored on disk are automatically loaded in memory when Meilisearch asks for them. This ensures LMDB will always make the best use of the RAM available to retrieve the documents.
 
-For the best performance, it is recommended to provide the same amount of RAM as the size the database takes on disk, so all the data structures can fit in memory.
+For best performance, Meilisearch works optimally when the full dataset fits in RAM. In practice, however, we consistently observe that a **RAM‑to‑disk ratio around 1/3 does not materially impact performance**, and for many workloads even ~1/10 works well. The effective memory requirement is highly use‑case‑dependent and varies with search and indexing pressure. RAM can be increased later to unlock more performance, but Meilisearch will not crash simply because the dataset size on disk exceeds the available RAM.
+
+Disk latency is also important for performance: using a **low‑latency disk** (for example, an NVMe SSD) will give better results than a **high‑latency disk** (for example, HDD, NFS, or other network‑mounted storage).
 
 ### Understanding LMDB
 
@@ -38,7 +40,7 @@ When deleting documents from a Meilisearch index, you may notice disk space usag
 
 Since LMDB is memory mapped, it is the operating system that manages the real memory allocated (or not) to Meilisearch.
 
-Thus, if you run Meilisearch as a standalone program on a server, LMDB will use the maximum RAM it can use. In general, you should have the same amount of RAM as the space taken on disk by Meilisearch for optimal performance.
+Thus, if you run Meilisearch as a standalone program on a server, LMDB will use the maximum RAM it can use. More RAM means more of the dataset stays in cache and fewer reads hit disk, but a [RAM‑to‑disk ratio of around 1/3 does not materially impact performance](#memory-mapping) for most workloads.
 
 On the other hand, if you run Meilisearch along with other programs, the OS will manage memory based on everyone's needs. This makes Meilisearch's memory usage quite flexible when used in development.