<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv=Content-Type content="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 11 (filtered medium)"> <style>  </style> </head> <body lang=EN-US link=blue vlink=purple> <div class=Section1> Hi,<o:p></o:p> In the process of testing path failover I noticed the following:<o:p></o:p> a) when the path is made unavailable(/dev/sdd) for a logical device “mp1” on a multipath target, the status of the path becomes [faulty][active]<o:p></o:p> mp1<o:p></o:p> [size=1 GB][features="0"][hwhandler="0"]<o:p></o:p> \_ round-robin 0 [enabled]<o:p></o:p> \_ 0:0:0:1 sda 8:0 [ready][active]<o:p></o:p> \_ round-robin 0 [active][first]<o:p></o:p> \_ 1:0:0:1 sdd 8:48 [faulty ][active]<o:p></o:p> <o:p> </o:p> b) When an dd is executed on /dev/mapper/mp1, the state of the paths is as follows<o:p></o:p> mp1<o:p></o:p> [size=1 GB][features="0"][hwhandler="0"]<o:p></o:p> \_ round-robin 0 [active][first]<o:p></o:p> \_ 0:0:0:1 sda 8:0 [ready][active]<o:p></o:p> \_ round-robin 0 [enabled]<o:p></o:p> \_ 1:0:0:1 sdd 8:48 [faulty ][failed]<o:p></o:p> <o:p> </o:p> <o:p> </o:p> b) Now if the path is made available for the same logical device (/dev/sdd), the status is as follows<o:p></o:p> mp1<o:p></o:p> [size=1 GB][features="0"][hwhandler="0"]<o:p></o:p> \_ round-robin 0 [active][first]<o:p></o:p> \_ 0:0:0:1 sda 8:0 [ready][active]<o:p></o:p> \_ round-robin 0 [enabled]<o:p></o:p> \_ 1:0:0:1 sdd 8:48 [ready ][failed]<o:p></o:p> <o:p> </o:p> Note the path /dev/sdd has become [ready][failed] not [ready][active].<o:p></o:p> <o:p> </o:p> Now if path /dev/sda is made unavailable, then if “dd” is run on /dev/mapper/mp1, it returns with input/output error, as none of the path will be in [ready][active] state. The following is the state now:<o:p></o:p> <o:p> </o:p> mp1<o:p></o:p> [size=1 GB][features="0"][hwhandler="0"]<o:p></o:p> \_ round-robin 0 [active][first]<o:p></o:p> \_ 0:0:0:1 sda 8:0 [faulty]][active]<o:p></o:p> \_ round-robin 0 [enabled]<o:p></o:p> \_ 1:0:0:1 sdd 8:48 [ready ][failed]<o:p></o:p> <o:p> </o:p> Kindly explain me what the two states for each path infer. Like [ready][active] or [faulty][active] or [faulty][failed] or [ready][failed]. Also let me know how to failover to other path (/dev/sdd) as it shows [ready][failed] status. If I execute just “multipath” tool from the command prompt the states get updated properly as<o:p></o:p> <o:p> </o:p> mp1<o:p></o:p> [size=1 GB][features="0"][hwhandler="0"]<o:p></o:p> \_ round-robin 0 [active][first]<o:p></o:p> \_ 0:0:0:1 sda 8:0 [faulty]][active]<o:p></o:p> \_ round-robin 0 [enabled]<o:p></o:p> \_ 1:0:0:1 sdd 8:48 [ready ][active]<o:p></o:p> <o:p> </o:p> After this I will be able to do IO using “dd”. I suspect that I haven’t configured my hotplug to call “multipath” tool as the path is made available/unavailable. I am not sure on where I get hotplug script for multipath and how to configure hotplug for calling the “multipath” tool. I appreciate if anyone can help me out in this regard.<o:p></o:p> <o:p> </o:p> Thanks and regards<o:p></o:p> Murthy<o:p></o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> </div> </body> </html>