Re: [Networker] Slow Win2k backup with lots of files

There is a metadata table stored at the tail end of the save set, and this
must be recovered before individual file restore begins. That could explain
what you have observed.

But I assure you that it is in fact a single pass on restore. Fragmentation
is not a problem for the restore itself. SnapImage never reverses the tape
once it begins the actual restore pass.

-----Original Message-----
From: Siobh án Ellis [mailto:siobhanellis AT HOTMAIL DOT COM] 
Sent: Wednesday, June 07, 2006 6:27 PM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: Re: Slow Win2k backup with lots of files

I've deployed it a couple of times.

You should deploy with a minimum version of 7.2.1 for NetWorker and 2.0.1 of

SnapImage, on Windows. This means you can use the DSA capability of 
NetWorker.

Full backups were about the same speed, but incremental backups were MUCH 
faster as it only backs up changed blocks.

It keeps a block map so it knows which blocks have changed. If the system 
that has SnapImage installed is rebooted, you must reload that block map, or

it will do a full backup again. Reloading the block map is not automatic.

I disagree with the previous statement about few problems with backing up to

tape. When you peform normal backups, you backup the whole file and so when 
you restore you restore the whole file. The problem with SnapIMage can be 
that you have blocks spread across many tapes and so a restore takes many 
tape loads. Each tape unload and load takes time, as does searching through 
the tape for the correct place on the tape for the block(s) you need.

If you backup to disk, and keep a whole cycle on disk, then this issue is 
obviated, and goes away.

If you have never done NDMP before, I would suggest getting professional 
services to help - make sure that who ever you get has done at least some 
form of NDMP before as there are things you need to know about NetWorker 
behaviour and NDMP. I have known EMC and EMC service providers to send 
anyone along to do the job. It should take, at most, 1 day to do with 
testing.

Siobhan Elis
EMC NetWorker Specialist
Independant Consultant
Sydney, Australia


>From: Shyam Hegde <hegde.shyam AT GMAIL DOT COM>
>Reply-To: Legato NetWorker discussion <NETWORKER AT LISTSERV.TEMPLE DOT EDU>,

>   Shyam Hegde <hegde.shyam AT GMAIL DOT COM>
>To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
>Subject: Re: [Networker] Slow Win2k backup with lots of files
>Date: Thu, 8 Jun 2006 02:09:05 +0530
>
>Hi,
>
>can anybody share their experience with NetWorker SnapImage those who have
>been using. What level of expertise is required and how complicated it is 
>to
>deploy and havethe solution work!
>
>Is it necessary for opting for EMC Professional Services ?
>
>Regards
>Shyam
>
>
>On 6/8/06, Steve Warren <swarren AT cresend DOT com> wrote:
>>
>>If you try the suggestions recommended here and it doesn't solve your
>>problem, I suggest you seriously consider SnapImage. It has it's 
>>limitations
>>but restore performance from tape is not the issue it's been represented 
>>to
>>be here. And on a big slow disk with millions of files, there's no faster
>>way to get file-granular backups to tape.
>>
>>SnapImage sorts all the file extents in the restore list  before it starts
>>so the restore is done in a single pass. Pieces get restored in tape order
>>and assembled on the fly. It's certainly no slower than restoring from a
>>normal multiplexed tape.
>>
>>There are things about it that are a little more cumbersome though so you
>>should make sure you really have a need for it before you go that 
>>direction.
>>
>> > > > I think that other person meant that maybe there'd be a way
>> > > > to use the "update" function within nsradmin to update the
>> > > > client's list of savesets to be backed up, in an automated fashion.
>> > >
>> > > I have no problem scripting nsradmin, but what does updating the
>>client
>> > > record more frequently accomplish?
>> >
>> > I read the message not that it needs to be terribly frequent, but that
>> > it needs to be automated so that human intervention isn't needed to 
>>pick
>> > up new folders.
>> >
>> > The frequency just gives the maximum time that can elapse between the
>> > creation (and population) of a folder and having it hit the backups.
>> > Daily would probably be sufficient in most environments.
>> >
>> > --
>> > Darren Dunham                                           
>>ddunham AT taos DOT com
>> > Senior Technical Consultant         TAOS            
>>http://www.taos.com/
>> > Got some Dr Pepper?                           San Francisco, CA bay 
>>area
>> >          < This line left intentionally blank to confuse you. >
>> >
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>> >
>>
>>--
>>
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