Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 58 insertions, 0 deletions

diff --git a/Documentation/device-mapper/striped.txt b/Documentation/device-mapper/striped.txt
new file mode 100644
index 00000000000..f34d3236b9d
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+++ b/Documentation/device-mapper/striped.txt
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+dm-stripe
+=========
+
+Device-Mapper's "striped" target is used to create a striped (i.e. RAID-0)
+device across one or more underlying devices. Data is written in "chunks",
+with consecutive chunks rotating among the underlying devices. This can
+potentially provide improved I/O throughput by utilizing several physical
+devices in parallel.
+
+Parameters: <num devs> <chunk size> [<dev path> <offset>]+
+    <num devs>: Number of underlying devices.
+    <chunk size>: Size of each chunk of data. Must be a power-of-2 and at
+                  least as large as the system's PAGE_SIZE.
+    <dev path>: Full pathname to the underlying block-device, or a
+                "major:minor" device-number.
+    <offset>: Starting sector within the device.
+
+One or more underlying devices can be specified. The striped device size must
+be a multiple of the chunk size and a multiple of the number of underlying
+devices.
+
+
+Example scripts
+===============
+
+[[
+#!/usr/bin/perl -w
+# Create a striped device across any number of underlying devices. The device
+# will be called "stripe_dev" and have a chunk-size of 128k.
+
+my $chunk_size = 128 * 2;
+my $dev_name = "stripe_dev";
+my $num_devs = @ARGV;
+my @devs = @ARGV;
+my ($min_dev_size, $stripe_dev_size, $i);
+
+if (!$num_devs) {
+        die("Specify at least one device\n");
+}
+
+$min_dev_size = `blockdev --getsize $devs[0]`;
+for ($i = 1; $i < $num_devs; $i++) {
+        my $this_size = `blockdev --getsize $devs[$i]`;
+        $min_dev_size = ($min_dev_size < $this_size) ?
+                        $min_dev_size : $this_size;
+}
+
+$stripe_dev_size = $min_dev_size * $num_devs;
+$stripe_dev_size -= $stripe_dev_size % ($chunk_size * $num_devs);
+
+$table = "0 $stripe_dev_size striped $num_devs $chunk_size";
+for ($i = 0; $i < $num_devs; $i++) {
+        $table .= " $devs[$i] 0";
+}
+
+`echo $table | dmsetup create $dev_name`;
+]]
+