Comments on: dm-multipath and the ds4700 http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/ Admin Spotting for Fun and Profit Fri, 11 Dec 2009 12:37:23 +0000 http://wordpress.org/?v=2.9 hourly 1 By: Thiago http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/comment-page-1/#comment-263 Thiago Wed, 30 Sep 2009 12:43:41 +0000 http://www.bofh-hunter.com/?p=161#comment-263 Got here when browsing for multipath.conf information on DS4xxx; just wanted to leave my .2c regarding one comment posted above, about removing devices.. I do not have any problems removing LUNs from recent Linux/kernel, there's no need for reboot. Are you making use of the "delete" attribute available under the disk/device on /proc ? Sample: echo 1 > /sys/bus/scsi/drivers/sd/0\:0\:6\:0/delete Of course you have to be sure that nobody is using the device. Got here when browsing for multipath.conf information on DS4xxx; just wanted to leave my .2c regarding one comment posted above, about removing devices.. I do not have any problems removing LUNs from recent Linux/kernel, there’s no need for reboot. Are you making use of the “delete” attribute available under the disk/device on /proc ?

Sample:
echo 1 > /sys/bus/scsi/drivers/sd/0\:0\:6\:0/delete

Of course you have to be sure that nobody is using the device.

]]> By: Jim Perrin http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/comment-page-1/#comment-242 Jim Perrin Thu, 03 Sep 2009 13:01:24 +0000 http://www.bofh-hunter.com/?p=161#comment-242 Also, thanks for the bugzilla links. Those should prove helpful also Also, thanks for the bugzilla links. Those should prove helpful also

]]> By: Jim Perrin http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/comment-page-1/#comment-241 Jim Perrin Thu, 03 Sep 2009 13:00:03 +0000 http://www.bofh-hunter.com/?p=161#comment-241 Yes, I've heard similar deprecation talk but I have yet to see any multipath configuration advice from LSI or IBM regarding the DS4XXX series. I worked with some @redhat.com folks to get things moving with the config above, but there are a couple issues where it could improve. Yes, I’ve heard similar deprecation talk but I have yet to see any multipath configuration advice from LSI or IBM regarding the DS4XXX series. I worked with some @redhat.com folks to get things moving with the config above, but there are a couple issues where it could improve.

]]> By: Jonathan Buzzard http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/comment-page-1/#comment-240 Jonathan Buzzard Thu, 03 Sep 2009 09:01:04 +0000 http://www.bofh-hunter.com/?p=161#comment-240 We where advised by LSI/IBM is that the RDAC drive is being depreciated in favour of dm-multipath. This was in response to asking why you cannot remove a device from a machine without rebooting, when I can do that just fine with a USB stick. There is also the issue of building a new RDAC initrd for a SAN booting machine following LSI's published procedure. Though that can be fixed with a simple patch to the RDAC makefile. However due to what I can only describe as bone headiness on the part of RedHat you still cannot SAN boot from a DS4000 series device using dm-multipath on RedHat/CentOS because the multipath error handler is not included in the initrd. The following bugs contain the bitch fest, it might be fixed in 5.5! https://bugzilla.redhat.com/show_bug.cgi?id=460899 https://bugzilla.redhat.com/show_bug.cgi?id=492052 We where advised by LSI/IBM is that the RDAC drive is being depreciated in favour of dm-multipath. This was in response to asking why you cannot remove a device from a machine without rebooting, when I can do that just fine with a USB stick.

There is also the issue of building a new RDAC initrd for a SAN booting machine following LSI’s published procedure. Though that can be fixed with a simple patch to the RDAC makefile.

However due to what I can only describe as bone headiness on the part of RedHat you still cannot SAN boot from a DS4000 series device using dm-multipath on RedHat/CentOS because the multipath error handler is not included in the initrd.

The following bugs contain the bitch fest, it might be fixed in 5.5!

https://bugzilla.redhat.com/show_bug.cgi?id=460899
https://bugzilla.redhat.com/show_bug.cgi?id=492052

]]> By: Jim Perrin http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/comment-page-1/#comment-239 Jim Perrin Thu, 03 Sep 2009 01:31:28 +0000 http://www.bofh-hunter.com/?p=161#comment-239 Currently the guidance I've seen from IBM is 'Use the rdac mpp driver from the lsi page'. I haven't seen any multipath.conf configs from them, which indeed is a bit odd. I don't claim to be the final resource, so if anyone's aware of an IBM blessed multipath.conf config, please let me know. Currently the guidance I’ve seen from IBM is ‘Use the rdac mpp driver from the lsi page’. I haven’t seen any multipath.conf configs from them, which indeed is a bit odd. I don’t claim to be the final resource, so if anyone’s aware of an IBM blessed multipath.conf config, please let me know.

]]> By: John McNulty http://www.bofh-hunter.com/2009/09/02/dm-multipath-and-the-ds4700/comment-page-1/#comment-238 John McNulty Wed, 02 Sep 2009 22:33:51 +0000 http://www.bofh-hunter.com/?p=161#comment-238 Don't IBM provide the correct details for you? I'm really surprised. HP provide an FC enablement kit for dm-multipath on RHEL 5.2 (and above) that populates multipath.conf with correct entries for all their supported FC SAN storage products. Works just great. Don’t IBM provide the correct details for you? I’m really surprised. HP provide an FC enablement kit for dm-multipath on RHEL 5.2 (and above) that populates multipath.conf with correct entries for all their supported FC SAN storage products. Works just great.

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