[PATCH] mtd-www: notes on when to use static and dynamic volumes

[PATCH] mtd-www: notes on when to use static and dynamic volumes

[Mark Deneen]

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This adds some documentation on when to use a static volume.  After
reading the documentation I had decided to make my squashfs root
static without knowing about a significant penalty to the boot time.
I have made some additions to the documentation to make this a little
bit more clear.

Best Regards,
Mark Deneen

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From a8cc7820fc599b9e7f366f89a194c676cc697b47 Mon Sep 17 00:00:00 2001
From: Mark Deneen <mdeneen@protonmail.com>
Date: Fri, 3 Apr 2020 16:27:07 -0400
Subject: [PATCH] additional notes on choosing between a static and a dynamic
 volume


 create mode 100644 0001-Fix-hyperlink-to-UBI-block-device.patch

diff --git a/0001-Fix-hyperlink-to-UBI-block-device.patch b/0001-Fix-hyperlink-to-UBI-block-device.patch
new file mode 100644
index 0000000..ad94a6c
--- /dev/null
+++ b/0001-Fix-hyperlink-to-UBI-block-device.patch
@@ -0,0 +1,22 @@
+From 4349c7156a7343279c8a1e66b0a651071da4df85 Mon Sep 17 00:00:00 2001
+From: Mark Deneen <mdeneen@protonmail.com>
+Date: Fri, 3 Apr 2020 15:54:04 -0400
+Subject: [PATCH] Fix hyperlink to UBI block device
+
+
+diff --git a/faq/ubi.xml b/faq/ubi.xml
+index f9a76b3..551959d 100644
+--- a/faq/ubi.xml
++++ b/faq/ubi.xml
+@@ -168,7 +168,7 @@ mount read-only file systems.</p>
+ 
+ <p>Yes. UBI allows to create a read-only block device on top of a UBI volume
+ which is suitable for read-only, block-oriented file systems, such as squashfs.
+-See the <a href="..doc/ubi.html#L_block">UBI block device</a> section for more details.</p>
++See the <a href="../doc/ubi.html#L_block">UBI block device</a> section for more details.</p>
+ 
+ <h2><a name="L_format_mtd">
+ 	Do I have to format my empty flash before running UBI on top of it?
+-- 
+2.20.1
+
diff --git a/doc/ubi.xml b/doc/ubi.xml
index 568a66e..1290735 100644
--- a/doc/ubi.xml
+++ b/doc/ubi.xml
@@ -109,6 +109,13 @@ volumes. Static volumes are read-only and their contents are protected by
 upper layers (e.g., a file-system) are responsible for ensuring data
 integrity.</p>
 
+<p>Static volumes are typically used for the kernel, initramfs, and dtb.
+Larger static volumes may incur a significant penalty when opening, as the
+<code>CRC-32</code> needs to be calculated at this time. If you are looking
+to use static volumes for anything besides the kernel, initramfs, or dtb you
+are likely doing something wrong and would be better off using a dynamic volume
+instead.</p>
+
 <p>UBI is aware of bad eraseblocks (i.e. portions of flash which wear
 out over time) and frees upper-level software from having to handle bad
 eraseblocks itself. UBI has a pool of reserved physical eraseblocks, and
-- 
2.20.1


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