From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=ALL_TRUSTED,BAYES_00 shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id E0F871F66E for ; Mon, 31 Aug 2020 04:33:37 +0000 (UTC) From: Eric Wong To: meta@public-inbox.org Subject: [PATCH] doc: expand on indexBatchSize regarding fragementation Date: Mon, 31 Aug 2020 04:33:37 +0000 Message-Id: <20200831043337.16695-1-e@80x24.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: And change the documentation reference in -tuning to point to the -index manpage while we're at it. --- Documentation/public-inbox-index.pod | 5 +++-- Documentation/public-inbox-tuning.pod | 6 ++++-- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/Documentation/public-inbox-index.pod b/Documentation/public-inbox-index.pod index 207b2ed8..936516f8 100644 --- a/Documentation/public-inbox-index.pod +++ b/Documentation/public-inbox-index.pod @@ -129,8 +129,9 @@ below. When using rotational storage but abundant RAM, using a large value (e.g. C<500m>) with C<--sequential-shard> can -significantly speed up the initial index and full C<--reindex> -invocations (but not incremental updates). +significantly speed up and reduce fragmentation during the +initial index and full C<--reindex> invocations (but not +incremental updates). Available in public-inbox 1.6.0 (PENDING). diff --git a/Documentation/public-inbox-tuning.pod b/Documentation/public-inbox-tuning.pod index b4e7698b..f5a25676 100644 --- 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 as documented in -L. +L. C 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 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 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