On May 3, 2013, at 12:03 PM, lst_hoe02 AT kwsoft DOT de wrote:
>
> Zitat von Francisco Garcia Perez <fgarpe AT gmail DOT com>:
>
>> Hello,
>> I have a PowerVault 124T, but I want buy a new backup system with support
>> for my old LTO-2 and LTO-3 tapes with at least 24 slots, 2 drives, a
>> barcode scanner. What do you recommend me?
>>
>
> If you really need support for reading your old LTO-2 tapes you are
> limited to LTO-4 because the read compatibility is maintained two
> steps down as far as i know. Instead of this you should rather use at
> least LTO-5 today and copy your data still needed from the old LTO
> tapes. As of brands recommended for tape libraries: Most of the
> mid-sized libraries (HP, IBM, Dell) are rebranded BDTs which work well
> with Bacula. For the tape drives some say that full-height are more
> solid than the half-height, but i don't have first hand experience for
> this.
Regarding the full-height vs. half-height issue, IMHO, it does benefit you to
read the small print.
In my case, we bought a Quantum SuperLoader3 LTO-4HH SAS, 16 Slots/2 Magazine
2U rack mount unit. I assumed at the time the HH (half-height) only affected
the physical form factor and nothing else. Turns out I was wrong. Puzzled by
the "slower" speeds I got with btape (65 to 78 MB/s), I took a hard look at the
data sheet for the SuperLoader3 family[1] and the explanation leapt out at me.
The quoted performance differs between the LTO-4HH and LTO-4 drives: 288
GB/hour vs 432 GB/hour (native speeds). The former equates to about 82 MB/s
whereas the latter parallels the LTO-4 spec max native speed of 120 MB/s.
So, there was a definite difference between going half-height and full-height
there. Unfortunately, for their LTO-4 SAS offerings, only (slower) half-height
was available. Fortunately, for LTO-5 and above, there was no documented speed
penalty for going half-height vs. full-height, so maybe Quantum have got their
engineering sorted out re: what was affecting their LTO-4 drives?
In all other respects, though, I have been very happy with the Quantum
SuperLoader3 LTO-4HH SAS unit. (I realise this doesn't meet the OP's
specifications, though.)
Cheers,
Paul.
[1] https://iq.quantum.com/exLink.asp?8357556OK69N63I33059211
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