Networker

Re: [Networker] virtual tape library / tape emulation products

2002-11-12 11:38:40
Subject: Re: [Networker] virtual tape library / tape emulation products
From: Terry Lemons <lemons_terry AT EMC DOT COM>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Tue, 12 Nov 2002 11:37:30 -0500
Hi Chris

Thanks for highlighting the pain involved in some aspects of the current
'file' device.  Legato has 'heard' you.  Stay tuned.

tl

-----Original Message-----
From: Chris Madden [mailto:maddenca AT myrealbox DOT com]
Sent: Tuesday, November 12, 2002 7:11 AM
To: Legato NetWorker discussion; lemons_terry AT emc DOT com;
WoodR AT ChevronTexaco DOT com
Subject: Re: [Networker] virtual tape library / tape emulation products


Although I haven't implemented backup to disk using a 'file' device other
than for testing I'd imagine the biggest pain would be the restriction of a
single concurrent operation.  So just like a tape device a file device can
have something reading, or something writing, but not multiple somethings
reading or writing (multiple sessions excepted).  If you create several
large LUNs you'll hit this restriction of only one activity happening on a
device at a time which would be a killer if you need to do multiple restores
that require the same device, or want to run a restore while backups are
still busy with the device.  On the other hand if you create smaller LUNs
you'll run into issues just trying to manage them all.  I know nothing of
tape emulation products or how they fit in so I can't comment on them...

Cheers,
-Chris
----- Original Message -----
From: "Terry Lemons" <lemons_terry AT EMC DOT COM>
To: <NETWORKER AT LISTMAIL.TEMPLE DOT EDU>
Sent: Monday, November 11, 2002 3:06 PM
Subject: Re: [Networker] virtual tape library / tape emulation products


Hi Bob

Thanks very much for sharing your thoughts!  From what I've been told, the
biggest attraction to virtual tape libraries is that, since they look like a
tape drive and all backup software can write to a tape drive, you can get
many of the benefits of writing to disk, without changing your backup
software.  Some backup software packages can not write to disk, or their
support for disk is limited to 'testing purposes only'.

So, if you could choose between a virtual tape library or backup-to-disk
(NetWorker's 'file' device), what would choose, and why?

Thanks
tl

-----Original Message-----
From: Wood, R A (Bob) [mailto:WoodR AT ChevronTexaco DOT com]
Sent: Saturday, November 09, 2002 2:29 PM
To: 'Legato NetWorker discussion'; 'lemons_terry AT EMC DOT COM'
Subject: RE: [Networker] virtual tape library / tape emulation products


Terry,
        I think it's time is here all right. But, looking a bit further
ahead, why restrict it to tape formats? Why does it have to look like tape
drives or tape libraries at all? The file device does just about all you
would want of a virtual jukebox.

        Do you think that a Networker server, connected to a SAN and having
several large LUNs on that SAN each configured as a file device would do the
same thing? Maybe even leveraging the SAN's utilities to copy the data to a
remote SAN for DR purposes?

        Don't get me wrong, I think the idea of a virtual tape device is
good but I think that it is a short term goal to virtualise the tape. If you
are going away from tape to disk storage or even solid state storage as the
main backup/recovery media it is an ideal opportunity to 'rethink' the whole
backup scenario.

        You've got to keep asking yourself 'Is there a better way?' I think
there is, and I think we're going to see it in the next few years...

Regards
Bob


-----Original Message-----
From: Terry Lemons [mailto:lemons_terry AT EMC DOT COM]
Sent: 08 November 2002 13:45
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] virtual tape library / tape emulation products

Hi

A posting to this mailing list about a specific virtual tape library prompts
me to learn more.  Please reply if you are using, or considering using a
virtual tape library or tape emulation product.  If you are using one, which
one, and how well is it working for you.  What do you think of the whole
idea of a virtual tape library - great idea whose time has come, or do you
just not see the need for one?

Thanks for the ensuing discussion!
tl

Terry Lemons
CLARiiON Application Solutions Engineering
        EMC²
where information lives

4400 Computer Drive, MS D239
Westboro MA 01580
Phone: 508 898 7312
Email: Lemons_Terry AT emc DOT com

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