Networker

Re: [Networker] Error reported when recovering data?

2011-01-20 22:58:40
Subject: Re: [Networker] Error reported when recovering data?
From: Preston de Guise <enterprise.backup AT GMAIL DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Fri, 21 Jan 2011 14:57:26 +1100
Hi George,

On 21/01/2011, at 14:48 , George Sinclair wrote:

> Using Linux RH with 7.5.1. I used nwrecover to recover a directory. 
> Everything appears to have been recovered, but the end of the output reports:
> 
> Received 31069 file(s) from NSR server `server'
> Recover errors with 1 file(s)
> Recover completion time: Fri Jan 21 00:35:48 2011
> 
> 
> recover command completed unsuccessfully on Fri Jan 21 00:35:48 2011
> 
> Also, it pops up the following error dialog box:
> 
> ##########################################################################
> The recover command completed with an unsuccessful exit code. View the 
> command output for more information as to why the command failed and possible 
> ways to correct the problem,
> 
> Exit code: 1
> ###########################################################################
> 
> I tried again using saveset recover, and basically the same thing happens.
> 
> I did save the output to a file. The output is lengthy, so I sorted it, and I 
> could see a line near the bottom concerning a file that grew during the save. 
> I then opened the file in an editor and searched for that line and part way 
> through, I see this:
> 
> ./monitor/logs/monitor.log.lck
> ./monitor/logs/monitor.log
> 32227:recover: `./monitor/logs/monitor.log' grew by 2585 bytes during save
> 
> ./monitor/logs/
> 
> I also see the following from the savegroup completion notification:
> 
> client: /home/log                  level=full,   3728 MB 00:15:35 32624 files
>     * <WARNING> :  Warning - `/home/log/monitor/logs/monitor.log' size grew 
> during save
>     * <WARNING> :  Expected 261118187 bytes for 
> `/home/log/monitor/logs/monitor.log', got 261120772 bytes
> 
> 1. Can I assume that this is in fact the error that the recover command was 
> reporting?

Yes, that's the most likely scenario. 

> 
> I have seen these messages for sundry files for other backups, and that's OK, 
> but I didn't think that the recover tool would complain about files that 
> changed during a save? Is that the normal behavior for both browsable 
> recovers and saveset recover?
> 

>From memory it was introduced somewhere in the 7.x series, thought it may have 
>been there earlier and I just didn't notice. It should be considered normal 
>behaviour. Effectively, recover is trying to warn you that some files restored 
>may not be consistent/correct because they weren't backed up that way.

> 2. How does NW know that a file grew during the save if you're doing a 
> saveset recover? Where is that information stored? It's not reading the index 
> during a saveset recover, right?

Presumably it would be part of the saveset stream on the media itself, as I 
agree, it wouldn't be consulting the index in this scenario. I would surmise 
that something is recorded in the saveset stream to note that the expected file 
size was X but it got Y.

> 3. I guess NW walks through the directory and takes a look at the file sizes 
> before the backup actually runs and so it knows that a given file's size has 
> changed just before it backs it up or maybe while it was backing it up? Not 
> surprising for log files. I could use logasm, but that only suppresses the 
> warning, right? I don't really care about the warning. Just wanted to find 
> out what the error is.

No, NetWorker does not do a pre-backup walk. It walks as it backs up. So the 
scenario would be:

walk
encounter file that needs to be backed up
note meta-details about file
backup
compare meta-details about file
warn if changed
continue walking

logasm isn't so much about suppressing the warning - it does that as a 
side-effect, but it's effectively you telling NetWorker "I don't care if this 
file changes during backup".

Cheers,

Preston.

--
Preston de Guise

http://nsrd.info/blog                           NetWorker Blog
http://www.enterprisesystemsbackup.com          "Enterprise Systems Backup and 
Recovery: A corporate insurance policy"

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