From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH] doc: expand on indexBatchSize regarding fragementation
Date: Mon, 31 Aug 2020 04:33:37 +0000 [thread overview]
Message-ID: <20200831043337.16695-1-e@80x24.org> (raw)
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<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>
@@ -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.
-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
next reply other threads:[~2020-08-31 4:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 4:33 Eric Wong [this message]
2020-08-31 23:43 ` [PATCH] doc: expand on indexBatchSize regarding fragmentation Eric Wong
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