From: "Darrick J. Wong" <djwong@us.ibm.com>
To: device-mapper development <dm-devel@redhat.com>
Cc: Heinz Mauelshagen <mauelshagen@redhat.com>
Subject: Maximum chunk size in dm-raid4-5.c
Date: Thu, 01 Jun 2006 17:45:42 -0700 [thread overview]
Message-ID: <447F8A36.30908@us.ibm.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1234 bytes --]
Hi,
Is there a particular reason why CHUNK_SIZE_MAX is set to 512 sectors in
the dm raid4/5 module? I have a fakeraid controller that can create
rather huge (1MB!) RAID5 stripes that this module rejects. I set it to
2048 and as far as I can tell there haven't been any adverse stability
effects, though I suspect that gigantic stripes do wonders for disk
throughput. :P
Attached is a patch to increase it to 2048 sectors. Please apply if
it's ok.
--D
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
--- a/drivers/md/dm-raid4-5.c 2006-06-01 17:42:27.000000000 -0700
+++ b/drivers/md/dm-raid4-5.c 2006-06-01 17:42:32.000000000 -0700
@@ -70,7 +70,7 @@
#define CHUNK_SIZE 64
/* Maximum setable chunk size in sectors */
-#define CHUNK_SIZE_MAX 512
+#define CHUNK_SIZE_MAX 2048
/* Recover chunk size in sectors */
#define RECOVER_CHUNK_SIZE CHUNK_SIZE_MAX
@@ -3114,7 +3114,7 @@ static int raid_ctr(struct dm_target *ti
chunk_size > CHUNK_SIZE_MAX ||
chunk_size & (chunk_size - 1))
TI_ERR("Invalid chunk size; must "
- "be 2^^n and less equal 512");
+ "be 2^^n and less equal 2048");
/*
* In case we've got 2 or more variable raid parameters,
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: dmraid45big.patch --]
[-- Type: text/x-patch; name="dmraid45big.patch", Size: 713 bytes --]
--- a/drivers/md/dm-raid4-5.c 2006-06-01 17:42:27.000000000 -0700
+++ b/drivers/md/dm-raid4-5.c 2006-06-01 17:42:32.000000000 -0700
@@ -70,7 +70,7 @@
#define CHUNK_SIZE 64
/* Maximum setable chunk size in sectors */
-#define CHUNK_SIZE_MAX 512
+#define CHUNK_SIZE_MAX 2048
/* Recover chunk size in sectors */
#define RECOVER_CHUNK_SIZE CHUNK_SIZE_MAX
@@ -3114,7 +3114,7 @@ static int raid_ctr(struct dm_target *ti
chunk_size > CHUNK_SIZE_MAX ||
chunk_size & (chunk_size - 1))
TI_ERR("Invalid chunk size; must "
- "be 2^^n and less equal 512");
+ "be 2^^n and less equal 2048");
/*
* In case we've got 2 or more variable raid parameters,
[-- Attachment #3: Type: text/plain, Size: 0 bytes --]
next reply other threads:[~2006-06-02 0:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-02 0:45 Darrick J. Wong [this message]
2006-06-02 6:07 ` Maximum chunk size in dm-raid4-5.c Heinz Mauelshagen
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