This is discussed at U2 University during my presentation. I highly
recommend that you all attend.
Also, the description stated UniVerse and not UniData, so I changed it.
Most people are skewed to only looking at their DB of choice.
JJUser asked However, I too am curious about the Server 2003 VSS (not
*nix, sorry!). Running it cannot cause corruption to the UniData files
even while people are logged in -- is that correct?
VSS is unproven at this point in time. To be specific, I don't think it
would be valid for one thing... When a file extends for overflow or a
dynamic file extends.
At that specific point in time, there are a number of writes that would
change the STRUCTURAL INTEGRITY of the file. Should not all of the writes
make it to disk, the file would be broken.
JJUser asked do the dbpause/dbstart or SUSPEND.ON/SUSPEND.OFF commands
ensure structural integrity to some extent? dbpause/dbresume ENSURE
Structural Integrity!!! This is your only method to ensure a complete
valid backup of the system.
dbpause suspends all writes and initiates the sync daemon (or the
equivalent command in Windows) to flush all unwritten writes to disk. It
does not continue to the next statement until this has been accomplished.
Like I said, exact details are covered in my U2 University presentation.
Register Now!
http://www-306.ibm.com/software/info/u2/university/index.jsp
At your service,
Steve
Stephen M. O'Neal
U2 Lab Services Sales Specialist
Information Management, IBM Software Group
jjuser ud2 [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
09/18/2007 02:44 AM
Please respond to
u2-users@listserver.u2ug.org
To
u2-users@listserver.u2ug.org
cc
Subject
Re: [U2] UniVerse and Shadow copy on Windows 2003
These are all extremely informative and lovely pieces of information
(no, that's not sarcasm):) With nice Unix information that can even
be applied to Windows with some thought.
However, I too am curious about the Server 2003 VSS (not *nix,
sorry!). Running it cannot cause corruption to the Unidata files even
while people are logged in -- is that correct?
From what I've read, Server 2003 lets the processes finish their disk
writes, pauses the processes on an OS level, writes the disk branching
information, and then resumes the processes. Programs wouldn't even
known it's happening.
Even deleting the VSS restore point is a safe operation as far as I
know in that it simply writes the new file indexes stored in the
restore points into the master file table, right?
That's where the VSS awareness comes in, right? Programs that are
aware could ensure data integrity through transactional logs. I'm
guessing it's the restore that would be the issue. Although the
processes would finish their writes, that would just be for one block
of data and you could be missing part of a record in a file or even
have inconsistencies between files if you tried to restore. Risky,
risky...
I guess my question now is: *on Windows*, do the dbpause/dbstart or
SUSPEND.ON/SUSPEND.OFF commands ensure structural integrity to some
extent, like Martin Phillips said earlier? If I start to write array
variable ABC containing 10,000 items 1000 characters each in length to
a file, and that file is only valid if ABC is completely written, will
it let ABC finish writing to that file? Will I have to check after
the restore if only 9,999 items were written?
On 9/17/07, Bertrand, Ron [EMAIL PROTECTED] wrote:
1) If you want to do any error tracking or suspend/unsuspend
verification flags you have to do it at the unix level - see #2!! I write
status flags out to the backup dir for the process.
2) We are running the process from from a backup cron (with root access)
and I found with that you need an account with a login voc that does not
run anything that writes to Universe files. Pretty obvious once you do
it!!!
The backup process is doing a cd //bkup and then /usr/ibm/uv/bin/uv
SUSPEND.ON, breaking a mirror and then a SUSPEND.OFFwith a resync later.
So far we average 4 seconds suspended.
Ron
From: [EMAIL PROTECTED] on behalf of David Jordan
Sent: Mon 9/17/2007 5:00 PM
To: u2-users@listserver.u2ug.org
Subject: RE: [U2] UniVerse and Shadow copy on Windows 2003
Hi Ron
Thanks for that. Are you aware of any issues I need to look out using
this?
Regards
David Jordan
Universe 10.2.2 on Solaris 10
ASSIGN 1 TO SYSTEM(43) to suspend
And 0 to un-suspend
Or UVSUSPEND.FILES ON/OFF (APP.PROGS/UVSUSPEND.B)
Ron Bertrand
---
u2-users mailing list
u2-users@listserver.u2ug.org
To unsubscribe please visit http://listserver.u2ug.org/
---
u2-users mailing list
u2-users@listserver.u2ug.org
To unsubscribe please visit http://listserver.u2ug.org/
---
u2-users mailing list
u2-users@listserver.u2ug.org
To unsubscribe please visit http://listserver.u2ug.org/
---
u2-users mailing list
u2-users@listserver.u2ug.org
To unsubscribe
