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

diff --git a/Documentation/public-inbox-tuning.pod b/Documentation/public-inbox-tuning.pod
index 58937f732dd157dd6be993ba01e7172337131041..53668eccb7cb85a7a7c0f6149c0c8c54189614e2 100644 (file)
--- a/Documentation/public-inbox-tuning.pod
+++ b/Documentation/public-inbox-tuning.pod
@@ -16,7 +16,7 @@ New inboxes: public-inbox-init -V2
 
 =item 2
 
 
 =item 2
 

-Process spawning
+Optional Inline::C use

 
 =item 3
 
 
 =item 3
 


@@ -34,6 +34,14 @@ Performance on solid state drives
 
 Read-only daemons
 
 
 Read-only daemons
 

+=item 7
+
+Other OS tuning knobs
+
+=item 8
+
+Scalability to many inboxes
+

 =back
 
 =head2 New inboxes: public-inbox-init -V2
 =back
 
 =head2 New inboxes: public-inbox-init -V2


@@ -42,7 +50,7 @@ If you're starting a new inbox (and not mirroring an existing one),
 the L<-V2|public-inbox-v2-format(5)> requires L<DBD::SQLite>, but is
 orders of magnitude more scalable than the original C<-V1> format.
 
 the L<-V2|public-inbox-v2-format(5)> requires L<DBD::SQLite>, but is
 orders of magnitude more scalable than the original C<-V1> format.
 

-=head2 Process spawning
+=head2 Optional Inline::C use

 
 Our optional use of L<Inline::C> speeds up subprocess spawning from
 large daemon processes.
 
 Our optional use of L<Inline::C> speeds up subprocess spawning from
 large daemon processes.


@@ -52,17 +60,16 @@ environment variable to point to a writable directory, or create
 C<~/.cache/public-inbox/inline-c> for any user(s) running
 public-inbox processes.
 
 C<~/.cache/public-inbox/inline-c> for any user(s) running
 public-inbox processes.
 

-More (optional) L<Inline::C> use will be introduced in the future
-to lower memory use and improve scalability.
-
-=head2 libgit2 usage via Inline::C
-

 If libgit2 development files are installed and L<Inline::C>
 is enabled (described above), per-inbox C<git cat-file --batch>
 processes are replaced with a single L<perl(1)> process running
 If libgit2 development files are installed and L<Inline::C>
 is enabled (described above), per-inbox C<git cat-file --batch>
 processes are replaced with a single L<perl(1)> process running

-C<PublicInbox::Gcf2::loop> in read-only daemons.
+C<PublicInbox::Gcf2::loop> in read-only daemons.  libgit2 use
+will be available in public-inbox 1.7.0+
+
+More (optional) L<Inline::C> use will be introduced in the future
+to lower memory use and improve scalability.

 
 

-Available as of public-inbox 1.7.0.
+Note: L<Inline::C> is required for L<lei(1)>, but not public-inbox-*

 
 =head2 Performance on rotational hard disk drives
 
 
 =head2 Performance on rotational hard disk drives
 


@@ -148,6 +155,26 @@ Transport Layer Security (IMAPS, NNTPS, or via STARTTLS) significantly
 increases memory use of client sockets, sure to account for that in
 capacity planning.
 
 increases memory use of client sockets, sure to account for that in
 capacity planning.
 

+=head2 Other OS tuning knobs
+
+Linux users: the C<sys.vm.max_map_count> sysctl may need to be increased if
+handling thousands of inboxes (with L<public-inbox-extindex(1)>) to avoid
+out-of-memory errors from git.
+
+Other OSes may have similar tuning knobs (patches appreciated).
+
+=head2 Scalability to many inboxes
+
+L<public-inbox-extindex(1)> allows any number of public-inboxes
+to share the same Xapian indices.
+
+git 2.33+ startup time is orders-of-magnitude faster and uses
+less memory when dealing with thousands of alternates required
+for thousands of inboxes with L<public-inbox-extindex(1)>.
+
+Frequent packing (via L<git-gc(1)>) both improves performance
+and reduces the need to increase C<sys.vm.max_map_count>.
+

 =head1 CONTACT
 
 Feedback encouraged via plain-text mail to L<mailto:meta@public-inbox.org>
 =head1 CONTACT
 
 Feedback encouraged via plain-text mail to L<mailto:meta@public-inbox.org>


@@ -160,6 +187,6 @@ L<http://4uok3hntl7oi7b4uf4rtfwefqeexfzil2w6kgk2jn5z2f764irre7byd.onion/meta/>,
 
 =head1 COPYRIGHT
 
 
 =head1 COPYRIGHT
 

-Copyright 2020-2021 all contributors L<mailto:meta@public-inbox.org>
+Copyright all contributors L<mailto:meta@public-inbox.org>

 
 License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>
 
 License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>