Hi All,
This is the follow-up question for multipathing support on Tru64
Unix. As a first step in analysing the multi-pathing on Tru64 Unix, I just
wanted to find out how the administrator will come to know that there is a
path failure in non-multipathing setup.
I used sysman to monitor the path failure for the juke box connected to my
system.
# sysman -menu "View events"
The following is the error file correspondinig to this.
*****************************************************************
======================= Binary Error Log event =======================
EVM event name: sys.unix.binlog.hw.scsi
Binary error log events are posted through the binlogd daemon, and
stored in the binary error log file, /var/adm/binary.errlog. This
event is used to report all SCSI device errors, including disk,
tape, HSZ raid events, and adapter errors.
======================================================================
Formatted Message:
SCSI event
Event Data Items:
Event Name : sys.unix.binlog.hw.scsi
Priority : 700
Timestamp : 30-Mar-2001 16:19:01
Host IP address : 20.240.20.220
Host Name : Unix51
Format : SCSI event
Reference : cat:evmexp.cat:300
Variable Items:
subid_class (INT32) = 199
subid_num (INT32) = 1
subid_unit_num (INT32) = 89
subid_type (INT32) = 34
binlog_event (OPAQUE) = [OPAQUE VALUE: 1096 bytes]
============================ Translation =============================
Sequence number of error: 146
Time of error entry: 30-Mar-2001 16:19:01
Host name: Unix51
SCSI CAM ERROR PACKET
Controller type: DISK
SCSI device class: DEC SIM
Bus Number: 1
Target number: 3
Lun Number: 1
Name of routine that logged the event: scsi_perform_timeout
Event information: timeout on disconnected request
############### Entry End ###############
Event information: Active CCB at time of error
############### Entry End ###############
======================================================================
*****************************************************************
Here the SCSI driver returned as error "SCSI CAM ERROR PACKET".
My question is that in a mulipathing environment, how the administrator
determines/monitors the path failure and how does the alternate path chosen?
Does administrator's presence is required in the identification of the
alternate path or is it done by controller/driver?
Cheers,
vsp
>From: "Prasad V.S." <vspra_at_hotmail.com>
>To: tru64-unix-managers_at_ornl.gov
>Subject: Summary: Multipathing in Tru64 Unix.
>Date: Wed, 21 Mar 2001 11:09:56
>
>Thanks to both Mr.Alen (alan_at_nabeth.cxo.dec.com ) and Dr.Thomas
>(Dr.Thomas.Blinn_at_Compaq.com)
>
>Here is the summary.
>
>Mr.Alan's
>
>Multipathing is handled in the SCSI driver.
>Unless explicit path selection was a required feature for the first
>release, it may be sometime for a API interface that allows path selection
>is available, if ever.
>
>Dr.Thomas's
>
>Not supported prior to V5.0, generally will not work correctly in V4.x.
>
>There are no APIs. There is no actual multipathing for storage for
>performance, all I/O is done through one path (to a given device) as long
>as the path works.
>
>Once again thanks,
>
>vsp.
>
>Original question
>
> >>Hi Managers,
>
> >> Do we have any specific APIs/layer interface for the >>multipathing in
>Tru64 Unix
> >>(Any version). (i.e For issuing IO's to storage LUN's through
> >>different paths,
> >>which increases the availability of storage in case of failure in any
> >>one path.
>
> >> And also I am interested to know how the Load Balancing, Path
> >>Verification, and
> >>Failover capability are done internally. Any pointers on this are
> >>really
> >>helpful.
>
> >>Many advanced thanks,
>
> >>Cheers,
>
> >>vsp.
>
>
>
>
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Received on Mon Apr 02 2001 - 13:11:34 NZST