Great stuff Joel.

Thanks.



----- Original Message -----
From: "Joel Fisher" <jfisher AT WFUBMC DOT EDU>
To: <NETWORKER AT LISTMAIL.TEMPLE DOT EDU>
Sent: Tuesday, August 26, 2003 4:19 PM
Subject: Re: [Networker] Advantages of disk to disk backup


> Hey Mark,
>
> I'm answering from personal research rather than experience...
>
> Most hardware vendors claim that you will get better backup speed...
> "Better" backup performance will be determined by how fast your current
> tape drives are and how you configure the disk that your File Type
> device resides on.  Since we have 60+ MB/s with compression drives, I
> doubt very seriously we will see any substantial performance.  I
> actually believe we will "lose" a little performance, but the gains IMHO
> outweigh the losses IMHO.
>
> The reasons we are heading towards D2D are below.
> Much more reliable "media".  D2D will virtually eliminate media
> errors(on the initial backup).
>
> The "random access" abilities of the Advanced File Type Device.
> (Although I think it is currently limited in legato.. only one stage or
> clone while doing backups)
>
> It should eliminate "tape" contention... ie when you're cloning a volume
> that contains an saveset that someone is trying to restore.
> Unfortunately due to some limitations of AFTD in legato you can't
> restore and clone from the same device, so this is still a problem.
> Possibly even a bigger problem because of the size(ie number of
> savesets) of the AFTD will probably be larger than any single tape. At
> least that is how it reads in the manual.  LEGATO PLEASE CHANGE THIS!!!
>
> The major advantage is that recovery times of nearline savesets will be
> almost immediate instead of having to wait for tape to be
> loaded/mounted/fsf/fsr then read from.  And many users can recover
> simultaneously with out contention.
>
> Another advantage is that you can start cloning immediately after you
> finish backing up because you tape drives will be dedicated for
> cloning/staging rather than for backups then cloning/staging.
>
> That's my 2 cents.
>
> I'm doing an eval of several different ATA based arrays in the next
> couple of months so I'll be able to give a better idea of performance
> issues after that is complete.  I'll be checking out the Nexsan ATAboy2,
> EMC Clariion CX600, StorageTek BladeStor, and NetApp NearStore.
>
> Yes your data would still traverse the network.  Unfortunately you'll
> have to weight the specific benefits/costs for your environment, but for
> ours I believe the benefits are worth the cost.  AFAIK you can use a SAN
> storage node to use SAN disk as a FTD, but then you can only backup
> "local disk" to that FTD.
>
> Please keep in mind that this is all based on what I read from the Admin
> Guide and other docs not from experience, so I could possible be
> interpreting sometime from the docs incorrectly.  Anyone feel free to
> correct my misconceptions.
>
> Have a good one,
>
>
> Joel
>
>
>
>
> Hi,  I am trying to determine the advantages of using disk to disk
> backup for a Networker server.  The networker server would have 500gb of
> disk and the total client data would be 200gb.  The client backups would
> be performed across the network as the disk is attached to the networker
> server. So my network will still be utilised by the backup,
>
> What kind of performance increase would I expect when using disk rather
> than tape? (I realise that the model of server/disk will effect this so
> in this case the disk will be internal to the compaq server).
> Will the benefits be enough to recommend disk to disk backup rather than
> a tape san?
> Can I configure a SAN storage node to use SAN disk as a file type
> device?
>
>
> Thanks and Regards,  Mark
>
>
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