[dm-devel] [PATCH] multipath-tools: add more info about max_sectors_kb in multipath.conf.5

[Xose Vazquez Perez]

Change of the default value in the kernel:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d2be537c3ba35

To query the device:
sg_inq -p 0xb0 /dev/sdX | grep "[ml] transfer length:"


Note: some arrays does not report any value.
      3PAR: 65534 blocks
      RDAC: not reported
      Hitachi VSP: query error

Cc: Martin Wilck <mwilck at suse.com>
Cc: Benjamin Marzinski <bmarzins at redhat.com>
Cc: Christophe Varoqui <christophe.varoqui at opensvc.com>
Cc: DM-DEVEL ML <dm-devel at redhat.com>
Signed-off-by: Xose Vazquez Perez <xose.vazquez at gmail.com>
---
 multipath/multipath.conf.5 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
index 8ef3a747..21963813 100644
--- a/multipath/multipath.conf.5
+++ b/multipath/multipath.conf.5
@@ -1240,9 +1240,11 @@ The default is: \fB0\fR
 .B max_sectors_kb
 Sets the max_sectors_kb device parameter on all path devices and the multipath
 device to the specified value.
+If the storage device(array, hard disk, ...) does not export the value to the
+system, the kernel sets it to 512(kernel < 4.3) or 1024(kernel >= 4.3).
 .RS
 .TP
-The default is: \fB<device dependent>\fR
+The default is: \fB<device dependent>\fR, or kernel provided if there is no value.
 .RE
 .
 .
-- 
2.30.1