Another consideration is that FC is faster than Ethernet. 8GB FC > 10GB FCoE
Ether-Over-Head is much greater than FC over-head.

Also, virtual tape libraries will fit nicely with your companies virtualization 
strategy, where file device class storage does not.

We currently use VTL, our next iteration of TSM (3 years) will most likely be 
File device class storage.

I would say there is no real advantage either way.  Both types of storage have 
unique "features".  For us the Ethernet network was not built to handle the 
data load to where our storage is and we had existing FC.


Andy Huebner


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Prather, Wanda
Sent: Monday, September 26, 2011 3:25 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] vtl versus file systems for pirmary pool

The one drop-dead difference is that if you want to do LAN-Free, the target has 
to be a tape (or tape-emulating) device.
Can't use TSM filepools.

If you replicate between VTL's, it's transparent to TSM, but you have to have 
the same vendor hardware at both sites.
Dedup may also be faster with a VTL, if your VTL does it in-line.
Also a VTL is often quicker to set up (which doesn't necessarily mean it is 
easier to maintain, if you consider firmware updates, multiple maintenance 
contracts, etc.)


TSM 6.2 has to dedup as part of the reclaim process, post-data-landing-there. 
That isn't necessarily a bad thing, it's just a different way.
To get replication of the deduped data, you have to set up a second/copy pool 
yourself; but it does not have to be the same hardware on both ends.

There is nothing about having a VTL/VTL gateway that inherently means you can 
do fewer concurrent backups than with a TSM filepool,  depends on your 
hardware.  You can have a fast VTL or a slow crappy VTL, just depends on what 
you pay for...





-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Tim Brown
Sent: Monday, September 26, 2011 4:05 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] vtl versus file systems for pirmary pool

What advantage does VTL emulation on a disk primary storage pool have

as compared to disk storage pool that is non vtl ?



It appears to me that a non vtl system would not require the daily reclamation 
process

and also allow for more client backups to occur simultaneously.



Thanks,



Tim Brown
Systems Specialist - Project Leader
Central Hudson Gas & Electric
284 South Ave
Poughkeepsie, NY 12601
Email: tbrown AT cenhud DOT com <<mailto:tbrown AT cenhud DOT com>>
Phone: 845-486-5643
Fax: 845-486-5921
Cell: 845-235-4255




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