Take in to consideration that the VTL's have limited bandwidth
regardless of Fibre connectivity so lets say you have a VTL head with 4
x 4gig fibre ports 1600MBS of bandwidth but your vtl head maxes out @
500-1000MBS. Then think of in a LAN free env, you have one VTL head
provide LAN free mount points so one DB host zoned to a VTL with 2 * 4gb
ports potentially pushing 400MBS to a head that supports 500-1000MBS so
you'll be dedicating a expensive VTL for one to two DB hosts backup? It
maybe cheaper to do Disk based snaps for large db's
Also take in to consideration cost of Fibre ports on your switch,
seprate FC HBA's for you hosts etc.
Charles
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Huebner,Andy,FORT WORTH,IT
Sent: Monday, September 26, 2011 4:04 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] vtl versus file systems for pirmary pool
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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