docs: Add tail-based sampling common problem (#11662) (#11681)

Document TBS high memory and high disk IO common problem.

(cherry picked from commit 1da1f38)

Co-authored-by: Carson Ip <carsonip@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

docs/common-problems.asciidoc

@@ -8,6 +8,7 @@ This section describes common problems you might encounter when using a Fleet-ma
 * <<common-ssl-problems>>
 * <<io-timeout>>
 * <<field-limit-exceeded-legacy>>
+* <<tail-based-sampling-memory-disk-io>>
 
 [float]
 [[no-data-indexed]]
@@ -187,3 +188,13 @@ In the agent logs, you won't see a sign of failures as the APM server asynchrono
 ----
 {\"type\":\"illegal_argument_exception\",\"reason\":\"Limit of total fields [1000] in [INDEX_NAME] has been exceeded\"}
 ----
+
+[[tail-based-sampling-memory-disk-io]]
+[float]
+=== Tail-based sampling causing high system memory usage and high disk IO
+
+Tail-based sampling requires minimal memory to run, and there should not be a noticeable increase in RSS memory usage.
+However, since tail-based sampling writes data to disk,
+it is possible to see a significant increase in OS page cache memory usage due to disk IO.
+If you see a drop in throughput and excessive disk activity after enabling tail-based sampling,
+please ensure that there is enough memory headroom in the system for OS page cache to perform disk IO efficiently.