I've got customers using both LTO4 and 3592 (now called TS1120) drives.
Both sets of customers are happy.
The TS1120 drives are fabulous - they are fast and have a really high duty
cycle. 3592 cartrdiges are more durable than the LTO4's.
The LTO4 drives are also excellent for the price.
The LTO4 drives are going to fail more often than the TS1120's, so keep them
under maintenance.
For the amount of data you process per day, I'd agree that the 3592's (while
a most excellent technology) are probably overkill in terms of the duty
cycle you need.
OTOH, the LTO4 drives will require a new library. The TS3500 library is my
favorite library out there; it is even more durable than the 3494, MUCH
faster, and a cleaner interface than the 3494 (no category codes to deal
with).
The other thing to consider: When you replace LTOx drives with the next
generation of LTO (which people tend to do in less than 5 years), you have
to replace all the media. When you replace your TS1120 drives (which people
generally don't need to do within 5 years), you get higher density on the
cartrdidge without replacing the media. For large sites, the LTO media
upgrade cost can exceed the drive upgrade cost.
Frankly, it's a no-lose situation for you, whether you choose LT04 or
TS1120.
And, as Kelly said, depending on the size of your total data store and your
DR requirements, a mostly-disk or partly-VTL solution may work very well,
too.
Which is optimal for you depends on the total amount of data you plan to
store, how long you want to keep this hardware, your DR
requirements, whether you have the comm lines available for replication,
your budget, your floorspace requirements. Etc.
Wanda
On 2/13/08, Kelly Lipp <lipp AT storserver DOT com> wrote:
>
> Johnny,
>
> How much total data do you have in primary pools?
>
> Tsm> audit licen
> Tsm> q auditocc pooltype=primary > auditocc.out
>
> I like Ken's idea: do as much disk as you can afford and LTO4 tape for
> DR. In your case, your DR data will fit on one LTO4 tape (and probably
> less than 1) per day and take perhaps four hours to write depending on
> how fast your disks are.
>
> Our hot spot solution for a site like yours is around 30TB of raw disk
> (we're waiting for TSM dedup) and an LTO4 library with two drives, 60
> slots or so (depending on the answer to your q auditocc). The libraries
> we're using are expandable up to 120 slots so we have growth and we can
> always add more disk. Compared to xx92 series tape drives, disk is
> pretty reasonable these days...
>
> Thanks,
>
> Kelly Lipp
> CTO
> STORServer, Inc.
> 485-B Elkton Drive
> Colorado Springs, CO 80907
> 719-266-8777
> www.storserver.com
>
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
> Of
> Bradberry, Kenneth
> Sent: Wednesday, February 13, 2008 11:04 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: [ADSM-L] TSM dream setup
>
> My dream setup has no tape, VTL disk, deduplicated and replicated to an
> off-site or hot site location. FalconStor and SEPATON are my two
> choices.
>
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
> Of
> Schneider, John
> Sent: Wednesday, February 13, 2008 11:56 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: TSM dream setup
>
> Johnny,
> We are in the process of migrating from an IBM3584 tape library
> with 3592 to another IBM3584 with LTO4. When we first got the LTO4 tape
> drives (last August) we got occasional I/O errors on them, but after a
> couple of firmware updates from IBM, they have been working just fine.
> We have done some significantly large test restores, and those have also
> worked without any problems.
> The LTO4 is being used for all the local storage pools, and the
> 3592 is being used for the copy storage pools. We would be completely
> off the 3592 drives by now if we weren't waiting for our DR vendor to
> support LTO4 drives.
>
> Best Regards,
>
> John D. Schneider
> Lead Systems Administrator - Storage
> Sisters of Mercy Health Systems
> 3637 South Geyer Road
> St. Louis, MO 63127
> Phone: 314-364-3150
> Cell: 314-486-2359
> Email: John.Schneider AT Mercy DOT net
>
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
> Of
> Johnny Lea
> Sent: Wednesday, February 13, 2008 10:38 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: [ADSM-L] TSM dream setup
>
>
> I'm looking for some ideas for upgrading/replacing my tsm servers and
> libraries. I backup about 800GB per night and have about 250 client
> nodes. I have a 7 year old Sun server connected to an IBM 3494 with six
> 3590 drives and a Dell 6800 with 22TB of disc connected to a LTO3
> library. I've thought about replacing the 3590 drives with 3592 but I'm
> thinking a new LTO4 library might be better.
>
> If you could get what you wanted what would it be?
>
> Thanks,
> Johnny
>
>
>
>
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