topic Shadowset Member Problem in Operating System - OpenVMS

Shadowset Member Problem

Farooq Saleem — Thu, 03 Dec 2009 12:25:41 GMT

Hi,

I have rx3600 attached with MSA30 via SCSI Cables. O/S is installed on MSA on DKA0 Disk. O/S is not loading and gives error

%SYSBOOT-F-LDFAIL, unable to load SYS$PUBLIC_VECTORS.EXE, status = 0000008C

There is a mirror disk DKD0, I boot the server from there using fs4: filesystem
through EFI Shell. Server booted successfully.

My Questions is that did both DKA0 and DKD0 are synchronized or not. If I boot the server from (DKA0 / fs0:) did it boot successfully or not. Mean, both DKA0 or DKD0 are synchronized now or not.

Re: Shadowset Member Problem

Richard Brodie_1 — Thu, 03 Dec 2009 13:17:51 GMT

$ exit (%x8C)
%SYSTEM-F-DRVERR, fatal drive error

It appears that DKA0 is faulty. I would assume it has been dropped from the shadowset.

Re: Shadowset Member Problem

Farooq Saleem — Thu, 03 Dec 2009 13:52:59 GMT

DKA0 and DKD0 both are member of shadow set

Re: Shadowset Member Problem

Farooq Saleem — Thu, 03 Dec 2009 13:55:31 GMT

Further more, If i wants to remove DKA0 from the shadow set, then what command should i run.

My purpose is that, first i remove the DKA0 from the shadow set and the make it member of shadow set again, so that date from DKD0 copied to DKA0.

Re: Shadowset Member Problem

Jon Pinkley — Thu, 03 Dec 2009 15:01:29 GMT

Farooq,

What do you mean by "There is a mirror disk DKD0"

Mirror usually means a controller based duplicate (raid 1). But you are also talking about shadowing, and that usually means host based synchronization of multiple disk copies.

I am a bit hesitant to make any recommendations, because the shadowing question you ask is pretty basic, and doing the wrong thing can do a lot of damage.

You need to provide more info, for example show the output of

$ show device /full dka0
$ show device /full dkd0

Jon

Re: Shadowset Member Problem

Hoff — Thu, 03 Dec 2009 15:03:35 GMT

What to do? How does shadowing work? How to replace a failed disk? Answers to all these questions and more are available in this document:

http://h71000.www7.hp.com/doc/732FINAL/DOCUMENTATION/PDF/aa-pvxmj-te.PDF

At its simplest (and barring cases where the disk error here is secondary to an error elsewhere in the configuration), you're going to replace the disk, MOUNT it into the shadowset, and wait for shadowing to copy the data over.

The basic command looks something like this:

MOUNT /CONFIRM /SYSTEM DSAu: /SHADOW=($n$DKA0) VolumeLabel

You'll need to customize that command to reflect your local system environment.

Re: Shadowset Member Problem

Hoff — Thu, 03 Dec 2009 15:05:03 GMT

And oh yeah, if you "miss" here and mis-specify a command, you'll clobber your data.

How current are your backups of your disks?

Re: Shadowset Member Problem

Farooq Saleem — Thu, 03 Dec 2009 15:14:38 GMT

Dear Jon,

My mistake, there is no hardware raid controller. this is host based synchronization or shadowing.

Re: Shadowset Member Problem

Jon Pinkley — Thu, 03 Dec 2009 15:27:17 GMT

Since this is evidently the system disk, and you claim that DKA0 and DKD0 are in a shadowset, please provide output from:

$ sho dev/ful sys$sysdevice

$ mcr sysgen show shadow_sys_disk

Re: Shadowset Member Problem

Jon Pinkley — Thu, 03 Dec 2009 15:39:38 GMT

If both DKA0 and DKD0 are currently members of the shadowset (as show device sys$sysdevice will show is true or not), then you can use

$ analyze/disk/shadow sys$sysdevice

to see if your disks are consistent.

See help analyze/disk/shadow for a more detailed description, and the shadowing manual (also you need the manual update from 8.2 new features or the HBMM patch for 7.3-2)

Shadowing is can be useful, but like fire, it can do a lot of damange if it isn't treated with respect. Getting a shadow copy with the wrong master member is non-recoverable (unless you have backups on some other media).

Re: Shadowset Member Problem

Farooq Saleem — Thu, 03 Dec 2009 16:51:15 GMT

Thankyou Hoff and John for helping me.

Special Thanks to Hoff for sharing such a nice document, it contains answers to all my questions. If it is possible to give more points, i will give you 100.

Re: Shadowset Member Problem

Farooq Saleem — Thu, 03 Dec 2009 16:54:03 GMT

I will issue dismount command for DKA0 and then mount it again as shadow set member.