LSM - Disassociated Plex During Volume Sync Process

From: George Guethlein <GGuethlein_at_GiantOfMaryland.com>
Date: Fri, 08 May 1998 11:14:02 -0500

Managers,
Any input or insight would be appreciated.....

Background:
1.) Alpha 4100, dual CPU, 512MB Mem
2.) root (UFS) is under LSM, rz9a mirrored to rz25a
3.) swap (UFS) is under LSM, rz9b mirrored to rz25b
4.) /usr (AdvFS) is under LSM, rz10d mirrored to rz26d
5.) /var (AdvFS) is under LSM, rz10e mirrored to rz26e
6.) Other filesystems (AdvFS), other disks, not mirrored
7.) Every time I "shutdown -r now", after the system comes
back up, the /usr filesystem starts an LSM sync process (30
to 40 minutes for the 1.2 GB). This doesn't occur on my
other four systems 2100, 4100's, 8400.

I am in the process of upgrading from 3.2F to 3.2G to 4.0A to
4.0B, and I've hit (actually, caused) a problem.

What Happened:
1.) Full system backup.
2.) Drop root disk mirrors.
3.) Unencapsulate root disk.
4.) Re-partition root disk (expanded root for 4.0).
5.) Restore root.
6.) Encapsulate root disk.
7.) Mirror root disk.

*** Many system boots to this point. Each extended 30-40
minutes due to /usr sync process, and I'm getting tired of it!

8.) Full system backup.
9.) Upgraded 3.2F to 3.2G.
10.) Doconfig procedures.

*** Up to this point EVERYTHING went OK.

*** NOW THE PROBLEM ***
11.) "shutdown -r now", to boot new kernel. System came
up OK, but the /usr sync process is running AGAIN !!!
12. "volplex dis volrz10d-01". (I was trying to DISPLAY the
plex for the /usr LSM volume).
13. "volplex dis volrz10d-02". Failed, can't detach last plex.

*** Now, I know what I did. "volplex dis xx" disassociates
the plex.

*** The volume now has one plex and is stuck in a "SYNC"
state.

14.) "volplex att volrz10d volrz10d-01", to reattach the plex.
(This seemed like the right thing to do ??)

*** The volume went into an "ENABLED ACTIVE" state, and
the plex was "ENABLED TEMP" with mode = "WO". I let
this sync process finish, and the volume and plex are both
"ENABLED ACTIVE" now.

*** The system is up and everything *** SEEMS *** fine. I
can start my Informix databases (thier home directories are
on /usr) and access them.

MY CONCERNS:
a.) Did I kill the good plex during the sync process ? If so,
then the data I now have on /usr was from the bad plex (the
plex being sync'd).

b.) I was the only one on the system, and I wasn't updating
/usr. So, what changed that made it sync up in the first
place ? Actually, why does it do this on EVERY boot ?

>>>>>>>> Info from DEC Tech Support <<<<<<<<
"shutdown -r now" IS NOT a clean process (it doesn't halt all
processes). But, "shutdown now", "sync;sync;sync;halt" is.

I tested this for a cycle, and the sync for /usr did NOT run.
>>>>>>>> Info from DEC Tech Support <<<<<<<<

*** I have to continue with the 4.0 upgrades, should I :

c.) Assume that /usr id OK and do the 4.0 upgrades ?

d.) Be positive (my co-workers call it anal !) and restore to
3.2F, and start over (the last backup I have is BEFORE the
3.2F to 3.2G upgrade).


I would really appreciate your suggestions.

Thanks, George

gguethelin_at_giantofmaryland.com
Lead Tech Sys Admin
Landover, MD USA
Received on Fri May 08 1998 - 17:16:19 NZST

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