doc: expand on indexBatchSize regarding fragmentation

[public-inbox.git] / Documentation / public-inbox-tuning.pod

diff --git a/Documentation/public-inbox-tuning.pod b/Documentation/public-inbox-tuning.pod
index e3f2899b76e58d90a22934f1d772beb3e8516816..f5a25676b7aab830b91c5679fd13e70041b10b28 100644 (file)
--- a/Documentation/public-inbox-tuning.pod
+++ b/Documentation/public-inbox-tuning.pod
@@ -74,7 +74,7 @@ sharding imposes a performance penalty for read-only queries.
 
 Users with large amounts of RAM are advised to set a large value
 for C<publicinbox.indexBatchSize> as documented in
 
 Users with large amounts of RAM are advised to set a large value
 for C<publicinbox.indexBatchSize> as documented in

-L<public-inbox-config(5)>.
+L<public-inbox-index(1)>.

 
 C<dm-crypt> users on Linux 4.0+ are advised to try the
 C<--perf-same_cpu_crypt> C<--perf-submit_from_crypt_cpus>
 
 C<dm-crypt> users on Linux 4.0+ are advised to try the
 C<--perf-same_cpu_crypt> C<--perf-submit_from_crypt_cpus>


@@ -95,7 +95,9 @@ Disabling copy-on-write also disables checksumming, thus C<raid1>
 Fortunately, these SQLite and Xapian indices are designed to
 recoverable from git if missing.
 
 Fortunately, these SQLite and Xapian indices are designed to
 recoverable from git if missing.
 

-Disabling CoW does not prevent all fragmentation.
+Disabling CoW does not prevent all fragmentation.  Large values
+of C<publicInbox.indexBatchSize> also limit fragmentation during
+the initial index.

 
 Avoid snapshotting subvolumes containing Xapian and/or SQLite indices.
 Snapshots use CoW despite our efforts to disable it, resulting
 
 Avoid snapshotting subvolumes containing Xapian and/or SQLite indices.
 Snapshots use CoW despite our efforts to disable it, resulting


@@ -131,7 +133,7 @@ for parallelism.
 
 The open file descriptor limit (C<RLIMIT_NOFILE>, C<ulimit -n> in L<sh(1)>,
 C<LimitNOFILE=> in L<systemd.exec(5)>) may need to be raised to
 
 The open file descriptor limit (C<RLIMIT_NOFILE>, C<ulimit -n> in L<sh(1)>,
 C<LimitNOFILE=> in L<systemd.exec(5)>) may need to be raised to

-accomodate many concurrent clients.
+accommodate many concurrent clients.

 
 Transport Layer Security (IMAPS, NNTPS, or via STARTTLS) significantly
 increases memory use of client sockets, sure to account for that in
 
 Transport Layer Security (IMAPS, NNTPS, or via STARTTLS) significantly
 increases memory use of client sockets, sure to account for that in