From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Landman Subject: Re: SES Enclosure Management. Date: Tue, 14 Feb 2012 15:58:30 -0500 Message-ID: <4F3ACAF6.4030004@gmail.com> References: <20120215073130.792d4fae@notabene.brown> <4F3AC741.6050204@gmail.com> <4F3AC9CB.3070707@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F3AC9CB.3070707@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Robert Woodworth Cc: NeilBrown , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 02/14/2012 03:53 PM, Robert Woodworth wrote: > On 02/14/2012 01:42 PM, Joe Landman wrote: >> On 02/14/2012 03:31 PM, NeilBrown wrote: >>> On Tue, 14 Feb 2012 10:30:37 -0700 Robert Woodworth >>> wrote: >>> >>>> Has anyone ever thought of integrating SES managed enclosures into the >>>> kernel RAID system? I briefly looked through the archives and have >>>> not found anything on the topic. >>>> >>>> Some HW based RAID controllers do this flawlessly now, there is no >>>> reason why the kernel RAID cannot also. (LSI MegaRAID) >>>> >>>> 1) When a drive is part if a managed enclosure, the RAID system should >>>> address it by location instead of by enumerated device node. The SES >>>> device in the enclosure can map the physical slot to a physical drive. >>>> The RAID admin (mdamd) should be able to add/fail/identify devices >>>> based on slot. >>> >>> Does this just mean that the admin should using names in >>> /dev/disk/by-path/ >>> rather than /dev/sdXX to address devices? What can md or mdadm do to >>> help? >>> >> >> Not sure on the SES (or SGPIO side), but one of the things we've been >> doing has been to create a file with disk placement "coordinates", so >> as to map serial number and device to physical location. >> > > With real SES managed enclosures, you issue a SCSI command to read SES > Page1 and Page2 to get the details about the drives in any given slot. > This currently works fine in Linux with the sg_utils3 package. From the > command line, 'sg_ses -p 2 /dev/sgXX` where the device is the SES device. > > Take a look at your systems, if you see a device at > /sys/class/enclosure/XXXX/ then you have a managed enclosure attached. > Got it. Thanks. Will look and see. Should be pretty straight forward to do this. > >>>> >>>> 2) If the RAID system fails a drive, it should notify the SES >>>> management and turn on the fail bit and the fail LED. >>> >>> "mdadm --monitor" will run a script on drive failure. This could easily >>> notify the SES management. >> >> Yes, we are using this now for notifications and logging. >> >>> >>> So maybe all we need here is a script to plug in to mdadm... Would >>> you like >>> to write one? >>> >> >> Just need a "standard" SES (or SGPIO) mechanism to hook into, and we >> should be able to support this. Right now we have to work through HBA >> scripts. > A true managed enclosure has nothing to do with the HBA. A managed > enclosure provides a device on the SCSI bus and you exclusively > communicate with that device regardless of the HBA. Most HW RAIDs (LSI > MegaRAID) will hide the SES device exactly like they hide the physical > disks. > Ok. Let me look to see if we can do this. If so, we should be able to help contribute some scripts. -- Joseph Landman, Ph.D Founder and CEO Scalable Informatics Inc. email: landman@scalableinformatics.com web : http://scalableinformatics.com http://scalableinformatics.com/sicluster phone: +1 734 786 8423 x121 fax : +1 866 888 3112 cell : +1 734 612 4615